Fatigue and Performance Rates as Decision-Making Criteria in Pacing Control During CrossFit®

We investigated fatigue and performance rates as decision-making criteria in pacing control during CrossFit®. Thirteen male regional-level competitors completed conditions of all-out (maximum physical work from beginning to end) and controlled-split (controlled physical work in the first two rounds but maximum work in the third round) pacing throughout the Fight Gone Bad workout separated by one week. We assessed benchmarks, countermovement jumps and ratings of fatigue after each round. Benchmarks were lower in round 1 (99 vs. 114, p < .001) but higher in rounds 2 (98 vs. 80, p < .001) and 3 (97 vs. 80, p < .001) for controlled-split compared with all-out pacing. Reductions in countermovement jumps were higher after rounds 1 (-12.6% vs. 1.6%, p < .001) and 2 (-12.7% vs. -4.0%, p = .014) but similar after round 3 (-13.2% vs. -11.3%, p = .571) for all-out compared with controlled-split pacing. Ratings of fatigue were higher after rounds 1 (7 vs. 5 a.u., p < .001) and 2 (8 vs. 7 a.u, p = .023) but similar after round 3 (9 vs. 9 a.u., p = .737) for all-out compared with controlled-split pacing. During all-out pacing, countermovement jump reductions after round 2 correlated with benchmark drops across rounds 1 and 2 (r = .78, p = .002) and rounds 1 and 3 (r = -.77, p = .002) and with benchmark workout changes between pacing strategies (r = -.58, p = .036), suggesting that the larger the countermovement jump reductions the higher the benchmark drops across rounds and workouts. Therefore, benchmarks, countermovement jumps and ratings of fatigue may assess exercise-induced fatigue as decision-making criteria to improve pacing strategy during workouts performed for as many repetitions as possible.

Effect of Menstrual Cycle Phase on Perceived Exertion During Aerobic Exercise in Eumenorrheic Women: A Systematic Review and Meta-analysis

Background

The rating of perceived exertion (RPE) is a readily available and practical tool widely used in exercise science to monitor exercise load, but a rigorous review of the effect of menstrual cycle (MC) phases on RPE within continuous aerobic exercise has not yet been completed.

Objective

This study investigated the effects of the MC phase on RPE during aerobic exercise.

Study Design

This was a systematic review and meta-analysis.

Methods

The search strategy was carried out using the 5 most common scientific databases. While qualitative analyses were performed in all included studies, random effects to standard mean difference were calculated and meta-analysis was performed where possible. This study addresses comparison for RPE at the beginning, middle, and end of the exercise adopting 2 mains analysis. The first adopted early cycle (first session of the cycle) as control compared with the subsequent phases, and the second adopted days 1 to 5 (early follicular) as control compared with the subsequent phases.

Results

A total of 17 studies (n = 160) were included in the qualitative synthesis. The meta-analysis showed that MC phases did not impact RPE (P > .05).

Conclusions

The current meta-analysis showed that MC does not impact RPE. Although acute RPE is not impacted by MC phases, future studies and practitioners should pay attention to the impact of RPE session by session throughout the MC.

Reference values for leg effort during incremental cycle ergometry in non-trained healthy men and women, aged 19-85

Heightened sensation of leg effort contributes importantly to poor exercise tolerance in patient populations. We aim to provide a sex- and age-adjusted frame of reference to judge symptom's normalcy across progressively higher exercise intensities during incremental exercise. Two-hundred and seventy-five non-trained subjects (130 men) aged 19-85 prospectively underwent incremental cycle ergometry. After establishing centiles-based norms for Borg leg effort scores (0-10 category-ratio scale) versus work rate, exponential loss function identified the centile that best quantified the symptom's severity individually. Peak O2 uptake and work rate (% predicted) were used to threshold gradually higher symptom intensity categories. Leg effort-work rate increased as a function of age; women typically reported higher scores at a given age, particularly in the younger groups (p < 0.05). For instance, "heavy" (5) scores at the 95th centile were reported at ~200 W (<40 years) and ~90 W (≥70 years) in men versus ~130 W and ~70 W in women, respectively. The following categories of leg effort severity were associated with progressively lower exercise capacity: ≤50th ("mild"), >50th to <75th ("moderate"), ≥75th to <95th ("severe"), and ≥ 95th ("very severe") (p < 0.05). Although most subjects reporting peak scores <5 were in "mild" range, higher scores were not predictive of the other categories (p > 0.05). This novel frame of reference for 0-10 Borg leg effort, which considers its cumulative burden across increasingly higher exercise intensities, might prove valuable to judging symptom's normalcy, quantifying its severity, and assessing the effects of interventions in clinical populations.

Influence of Ambient Temperature on Autonomic Nerve Function and Peripheral Sensation from Moderate-Intensity Treadmill Exercise

Objective

The main objective was to ascertain the acute responses in autonomic nervous activity and peripheral sensation induced by moderate-intensity treadmill exercise performed under different ambient temperatures.

Methods

Twelve young healthy subjects underwent three sessions of moderate-intensity treadmill exercise (warming, 5 min and running, 25 min), on different days under 10°C, 20°C and 30°C room temperatures. Pre- and post-intervention, heart rate variability (HRV) and plantar vibrotactile perception threshold (VPT) were measured. Additionally, rate of perceived exertion (RPE) was recorded after intervention.

Results

In comparison with the corresponding baseline values, after intervention, low frequency power (LF) and LF/high frequency power (HF) of HRV increased significantly and HF decreased significantly under the condition of 10°C only (p < .005). Following intervention, VPT increased significantly at the hallux for 31.5 Hz test frequency under 30°C and at the heel for 31.5 Hz test frequency under 10°C (both p < .05). In contrast, VPT decreased significantly at the hallux for 125 Hz test frequency under 10°C (p < .005). Exposure under the temperature of 20°C did not result in any significant change in VPT. After intervention, RPE under 30°C showed significantly higher values than those under 20°C (p < .01) and 10°C (p < .005) conditions with no difference between the latter two conditions.

Conclusions

Treadmill exercise under 20°C ambient temperature did not exert any negative impacts on autonomic and peripheral nerve function and resulted in a perceived exertion of moderate intensity among the study participants. Therefore, an ambient temperature around 20°C might be recommended for the mentioned purpose.

Absence of Monotony and Strain Effects on Referees' Physical Performance During International Basketball Federation World Cup Basketball Competition

PURPOSE

The study aimed to conduct a comparative analysis of physical performance indicators and assess the levels of performance monotony and strain experienced by basketball referees.

METHODS

The study involved the participation of 12 basketball referees (mean age: 40.0 [4.9] y) affiliated with the International Basketball Federation. The investigation was carried out throughout 2 density tournaments, wherein the maximum heart rate, average heart rate, performance monotony, and performance strain were documented for 3 variables.

RESULTS

The findings indicated significant variations in the mean heart rate, maximum heart rate, total distance monotony, total distance strain, the total number of sprints monotony, the total number of sprints strain, calories monotony, and calories strain (P < .05). Decreasing the density of elite-level basketball competitions has been observed to reduce the monotony and strain experienced by referees. However, this action does not increase motion distance or speed zones.

CONCLUSIONS

The environmental stressors experienced by senior-level athletes (World Cup) differ from those encountered by younger athletes (World Cup Under 19). Further investigation is required to ascertain the potential effects of competition monotony and strain on decision-making processes and the overall quality of refereeing.

Effects of Acute Physical Fatigue on Gaze Behavior in Expert Badminton Players

Perceptual cognitive skills in real game settings, under conditions of fatigue, such as the ability to gather relevant visual information, are key factors in achieving motor goals in sports. The objectives were to evaluate the effects of acute physical fatigue on gaze behavior during a badminton game (Study 1) and in an unfavorable force ratio situation (Study 2). Six international-level badminton players played two sets and unfavorable force ratio situations while wearing eye-tracking glasses before and after a fatiguing task. During the set, fatiguing physical exercise led to fewer fixations per exchange and more fixations on one area of interest. During unfavorable force ratio situations, fatiguing physical exercise led to shorter fixation durations per exchange, shorter fixation durations on two areas of interest, and longer fixation durations on one area of interest. The results showed that gaze behaviors were adapted in acute physical fatigue conditions to maintain performance.

The effect of fatigue on spike jump biomechanics in view of patellar tendon loading in volleyball

BACKGROUND AND OBJECTIVE

Patellar tendinopathy (PT) is a highly prevalent overuse injury in volleyball and is often linked with overloading of the patellar tendon. Little is known, however, about whether and how patellar tendon loading is affected by fatigue during the most challenging jump activity in volleyball. Therefore, this study investigates the effect of a high-intensity, intermittent fatigue protocol on movement alterations in terms of patellar tendon loading during a volleyball spike jump.

METHODS

Forty-three male volleyball players participated in this study. Three-dimensional full-body kinematics and kinetics were collected when performing a spike jump before and after the fatigue protocol. Sagittal plane joint angles, joint work and patellar tendon loading were calculated and analyzed with curve analyses using paired sample t-tests to investigate fatigue effects (p < 0.05).

RESULTS

Fatigue induced a stiffer lower extremity landing strategy together with prolonged pelvis-trunk flexion compared to baseline (p = 0.001-0.005). Decreased patellar tendon forces (p = 0.001-0.010) and less eccentric knee joint work (-5%, p < 0.001) were observed after the fatigue protocol compared to baseline.

CONCLUSION

Protective strategies seem to be utilized in a fatigued state to avoid additional tensile forces acting on the patellar tendon, including proximal compensations and stiff lower extremity landings. We hypothesize that players might be more prone for developing PT if eccentric patellar tendon loads are high in the non-fatigued state and/or these loads are somehow not decreased after fatigue.

A cohort study of retinal detachment among Swedish construction workers

OBJECTIVE

Retinal detachment (RD) has been associated with exposure to heavy lifting. Many occupations within the construction industry are likely to involve lifting tasks. We investigated the association between occupational heavy lifting and rhegmatogenous RD in a retrospective cohort study of Swedish construction workers.

METHODS

We studied Swedish construction workers who participated in an industry-wide health and safety program from 1971 to 1993. Individual occupation codes were linked to a job exposure matrix, assigning intensity of exposure to heavy lifting to each worker. The Swedish National Patient Register was used to identify cases of RD that occurred during follow-up through the end of 2012. We used Poisson regression modeling to calculate incidence rates of RD associated with heavy lifting, age and other covariates. A subcohort of those age ≤25 years at enrollment was studied to reduce bias from missing exposure information from work prior to enrollment.

RESULTS

Of 256 241 construction workers, 17% were classified with high exposure to heavy lifting in their occupation. Within the cohort, 1588 cases of RD were identified. Average exposure intensity of heavy lifting was not associated with risk of RD. However, RD risk increased with increasing cumulative exposure to heavy lifting, both in the full cohort and subcohort of those who were ≤25 years old at entry into the construction-worker cohort.

CONCLUSION

Construction workers' risk of RD appeared to increase with time spent exposed to heavy lifting.

The relevance of body composition assessment for the rating of perceived exertion in trained and untrained women and men

Introduction: Mechanic power output (MPO) and oxygen consumption (VO2) reflect endurance capacity and are often stated relative to body mass (BM) but less often per skeletal muscle mass (SMM). Rating of perceived exertion (RPE) has previously shown conflicting results between sexes at submaximal intensities. Individual body composition, however, largely differs due to sex and training status. It was the aim of this study to evaluate RPE of untrained and trained individuals of both sexes considering body composition and to estimate whether RPE could be improved as a tool to determine endurance capacity. Methods: The study included 34 untrained adults (age 26.18 ± 6.34 years, 18 women) and 29 endurance trained (age 27.86 ± 5.19, 14 women) who were measured for body composition (InBody 770, InBody Europe B.V., Germany) and tested on a treadmill (Pulsar, H/P/Cosmos, Germany) for aerobic capacity (Metalyzer 3B, Cortex Biophysik GmbH, Germany) in an all-out exercise test applying the Bruce-protocol. VO2, MPO, heart rate (HR), and RPE were obtained at each exercise stage. VO2 and MPO were calculated per BM and SMM. RPE values were correlated with absolute VO2 and MPO, as well as relative to BM, and SMM. HR values and the parameters' standardized values served for comparison to standard procedures. Results: VO2 and MPO were higher in men compared to women and in trained compared to untrained participants. No differences between groups and sexes exist when VO2 and MPO were calculated per BM. When calculated per SMM, VO2 and MPO indicate opposite results already at low intensity stages of exercise test. RPE values had highest correlation with MPO per SMM (R2 = 0.8345) compared to absolute MPO (R2 = 0.7609), or MPO per BM (R2 = 0.8176). Agreement between RPE and MPO per SMM was greater than between RPE and HR (p = 0.008). Conclusion: Although RPE represents a subjective value at first glance, it was shown that RPE constitutes a valuable tool to estimate endurance capacity, which can be further enhanced if individual body composition is considered. Furthermore, MPO and VO2 should be considered relative to SMM. These findings might help to avoid over-exertion, especially among untrained people, by adjusting the training intensity for each subject according to the individual strain evaluated in an exercise test based on individual body composition.

The Effects of Anchor Schemes on Performance Fatigability, Neuromuscular Responses and the Perceived Sensations That Contributed to Task Termination

The present study examined the effect of anchor schemes on the time to task failure (TTF), performance fatigability, neuromuscular responses, and the perceived sensations that contributed to task termination following the sustained, isometric forearm flexion tasks. Eight women completed sustained, isometric forearm flexion tasks anchored to RPE = 8 (RPEFT) and the torque (TRQFT) that corresponded to RPE = 8. The subjects performed pre-test and post-test maximal isometric contractions to quantify performance fatigability and changes in electromyographic amplitude (EMG AMP) and neuromuscular efficiency (NME). In addition, the subjects completed a post-test questionnaire (PTQ) to quantify the contributions of perceived sensations to task termination. Repeated measure ANOVAs were used to assess the mean differences for TTF, performance fatigability, and neuromuscular responses. Wilcoxon Signed Rank Tests were used to assess the differences between anchor schemes for the average values from the PTQ item scores. For TTF, the RPEFT was longer than the TRQFT (174.9 ± 85.6 vs. 65.6 ± 68.0 s; p = 0.006). Collapsed across the anchor scheme, there were decreases in torque (23.7 ± 5.5 Nm vs. 19.6 ± 4.9 Nm; p < 0.001) and NME (1.00 ± 0.00 vs. 0.76 ± 0.15; p = 0.003). There were no significant (p > 0.577) changes for EMG AMP. For the PTQ, there were no differences (p > 0.05) between anchor schemes. There were, however, inter-individual differences in the response scores. The current findings indicated that performance fatigability was likely due to peripheral fatigue (based on NME), not central fatigue (based on EMG AMP). Furthermore, the use of a PTQ may serve as a simple tool to assess the contributions of perceived sensations to task termination.

Manual Wheelchair Configuration in Unilateral Upper and Lower Extremity Propulsion: A Randomized Crossover Study to Assess Effects of Rear Wheel Axle Position and Frame Type

OBJECTIVE

The purpose of this study was to evaluate independence and exertion when using a lightweight wheelchair in comparison to ultra-lightweight wheelchairs (rigid and folding) for individuals with brain injury (BI) using a hemi-propulsion technique.

DESIGN

Randomized Cross-Over SETTING: Rehabilitation Hospital PARTICIPANTS: Individuals diagnosed with BI resulting in hemiplegia using a hemi-propulsion technique to mobilize in a manual wheelchair for at least four hours per day were recruited for this study.

INTERVENTIONS

Participants were randomly assigned to complete skills and endurance testing in three different wheelchair configurations over a three week period: light weight wheelchair; ultra-lightweight folding wheelchair; ultra-lightweight rigid wheelchair.

MAIN OUTCOME MEASURES

The primary outcome in this study was the percentage capacity score from the modified Wheelchair Skills Test (WST) 4.1. Secondary outcomes included the wheelchair Propulsion Test (WPT), 100 m Push Test, Heart Rate (HR) and Rate of Perceived Exertion (RPE).

RESULTS

Significant differences were found in the WST (total score, low rolling resistance score and the goal attainment score) favoring the ultra-lightweight wheelchairs over the lightweight wheelchair (p=0.002, 0.001, and 0.016 respectively). Time to complete the 100m push test was significantly faster for the ultra-lightweight rigid frame in comparison to the lightweight frame (p= 0.001; 30.89 seconds faster). Significance differences were not seen with the WPT measures across any of the wheelchair frames. HR change and RPE was significantly lower for the ultra-lightweight rigid group in comparison to the lightweight group (p=0.006 and 0.013 respectively).

CONCLUSIONS

This data suggests that using an ultra-light weight wheelchair may lead to improved ability to complete wheelchair skills needed for successful mobility and a decrease in the actual and perceived physiological burden associated with propulsion in comparison to a lightweight wheelchair. A rigid frame may also enable faster mobility in comparison to a folding frame when hemi-propelling.

Pediatric Functional Neurological Symptoms Disorder: Walking Ability and Perceived Exertion Post-Pediatric Rehabilitation

BACKGROUND

Adolescents with functional neurological symptoms disorder (FNSD) commonly present walking abnormalities. Walking is influenced by 'objective' (e.g., fitness) and 'subjective' (e.g., fear) components. Rate of perceived exertion (RPE) reflects the interaction between these two components. This study compared the walking ability and RPE before and after rehabilitation of adolescents with FNSD to adolescents with moderate-to-severe traumatic brain injury (TBI). Factors predicting walking and RPE were also examined.

METHODS

Adolescents with FNSD (n = 31) and adolescents with moderate-to-severe TBI (n = 28) aged 6 to 18 years participated in the study. Participants received a multidisciplinary rehabilitation program. Six-minute walk test (6MWT) and RPE were assessed before and after rehabilitation.

RESULTS

At pre-test, the TBI group presented lower RPE than the FNSD group (3.38 ± 2.49 and 6.25 ± 2.71, respectively). In the FNSD group, pre-test 6MWT was a significant predictor of post-test 6MWT (adjusted R2 = 0.17; p = 0.01). In the TBI group, post-test 6MWT was significantly predicted by both the pre-test 6MWT and age (adjusted R2 = 0.16; p = 0.04).

CONCLUSIONS

Prior to the intervention, adolescents with FNSD perceived walking as a more difficult activity than adolescents with TBI. Post-intervention, although the intervention was effective in terms of changes in 6MWT and RPE, the 'subjective' component still contributed to the elevated RPE of the FNSD group.

Sensorimotor Cortex GABA Moderates the Relationship between Physical Exertion and Assessments of Effort

Experiences of physical exertion guide our assessments of effort. While these assessments critically influence our decisions to engage in daily activities, little is known about how they are generated. We had female and male human participants exert grip force and assess how effortful these exertions felt; and used magnetic resonance spectroscopy to measure their brain GABA concentration. We found that variability in exertion (i.e., the coefficient of variation in their force exertion profile) was associated with increases in assessments of effort, making participants judge efforts as more costly. GABA levels in the sensorimotor cortex (SM1) moderated the influence of exertion variability on overassessments of effort. In individuals with higher sensorimotor GABA, exertion variability had a diminished influence on overassessments of effort. Essentially, sensorimotor GABA had a protective effect on the influence of exertion variability on inflations of effort assessment. Our findings provide a neurobiological account of how the brain's GABAergic system integrates features of physical exertion into judgments of effort, and how basic sensorimotor properties may influence higher-order judgments of effort.SIGNIFICANCE STATEMENT Feelings of effort critically shape our decisions to partake in activities of daily living. It remains unclear how the brain translates physical activity into judgments about effort (i.e., "How effortful did that activity feel?"). Using modeling of behavior and neuroimaging, we show how the nervous system uses information about physical exertion to generate assessments of effort. We found that higher variability in exertion was associated with increases in assessments of effort, making participants judge efforts as more costly. GABA, the brain's main inhibitory neurotransmitter, moderated the influence of exertion variability on overassessments of effort. These findings illustrate how low-level features of motor performance and sensorimotor neurochemistry influence higher-order cognitive processes related to feelings of effort.

Test-Retest, Interrater Reliability, and Minimal Detectable Change of the Dynamic Exertion Test (EXiT) for Concussion

BACKGROUND

The Dynamic Exertion Test (EXiT) was developed to inform return-to-play (RTP) decision-making following clinical recovery from sport-related concussion (SRC). The purpose of the current study was to document intrarater and test-retest reliability and minimal detectable change (MDC) scores for physiological [heart rate (HR) and blood pressure], performance (change-of-direction task completion time and errors), and clinical outcomes (endorsed symptoms, perceived exertion) of EXiT, and interrater reliability of performance outcomes.

HYPOTHESIS

Healthy athletes would exhibit stable physiological responses to the EXiT across visits, demonstrate consistent change-of-direction task completion time between consecutive trials at each visit, and the fastest time (of 2 trials) across visits, and endorse equivocal symptoms and effort across visits.

STUDY DESIGN

Cross-sectional, test-retest.

LEVEL OF EVIDENCE

Level 3.

METHODS

Seventy-nine (female: 34 [43%], 19.6 ± 5.0 years) athletes completed the EXiT at 2 study visits (8.7 ± 4.7 days between visits). Two-way, mixed, intraclass correlation coefficients (ICCs) were used to evaluate intrarater and test-retest reliability. Cronbach's alpha was used to document the internal consistency of symptoms at each visit, and MDC scores were calculated on the physiological, performance, and clinical outcomes.

RESULTS

Measured and percentage of age-estimated maximum HR were reliable following EXiT (ICC = 0.579-0.618). Change-of-direction task completion time (MDC range = 0.75-8.70 s) had good-to-excellent test-retest (ICC = 0.703-0.948) and interrater (ICC = 0.932-0.965) reliability. Symptoms had a high internal consistency at visits 1 (α = 0.894) and 2 (α = 0.805) and were reliable across visits (ICC = 0.588).

CONCLUSION

The current investigation established test-retest reliability in addition to MDC scores of an objective dynamic exercise assessment among healthy adolescent and adult athletes. The EXiT may be an objective approach to inform RTP decision-making following SRC recovery.

CLINICAL RELEVANCE

The EXiT is a clinically feasible exertion-based assessment that can be readily administered in a variety of outpatient clinical settings.

Evaluation of a Chair-Mounted Passive Trunk Orthosis: A Pilot Study on Able-Bodied Subjects

Trunk stability is important for adequate arm function due to their kinematic linkage. People with Duchenne muscular dystrophy (DMD) can benefit from trunk-assistive devices for seated daily activities, but existing devices limit trunk movement to forward bending. We developed a new trunk orthosis that has spring and pulley design. This study evaluated orthosis performance with 40 able-bodied subjects under with and without orthosis condition in 20 seated tasks for trunk rotation, forward bending, and side bending movements. Subjects adopted static posture in specific trunk orientation while their muscle activity was recorded. They also rated the subjective scales of perceived exertion and usability. A percent change in muscle activity for each task, due to orthosis use, is reported. Significant muscle activity reductions up to 31% and 65% were observed in lumbar and thoracic erector spinae muscles, respectively. Using three-way ANOVA, we found these reductions to be specific to the task direction and the choice of upper limb that is used to perform the asymmetric tasks. A total of 70% participants reported acceptable usability and ~1-point increase in exertion was found for maximum voluntary reaching with the orthosis. The outcomes of this study are promising, though tested on able-bodied subjects. Hence, orthosis mounted on wheelchairs should be further evaluated on DMD patients.

The effect of descriptive norms and social identification on performance and exertion during a physical fitness task

Research suggests that people's perceptions of the typical physical activity behaviors of others-descriptive norms-shape their own physical activity. However, prior work has primarily used cross-sectional designs, focused on people's physical activity intentions or self-reported overall physical activity, and failed to attend to how the normative referent affects the norm-behavior relationship. In a pre-registered experiment, we manipulated the descriptive norm to explore its effect on perceived exertion during, and objectively assessed performance on, an exercise (running) task. We also measured the strength of participants' social identification as a member of the norm reference group as a potential moderator. Following a baseline trial, participants (N = 78) were either told that their baseline score on the running task was below average (high norm condition) or above average (low norm condition) compared to members of the reference group. Participants in both conditions tended to perform better in Trial 2 than Trial 1. However, participants in the high norm condition improved their performance significantly (2.5 times) more than participants in the low norm condition. Social identification moderated the effect of the norm manipulation on perceived exertion. High identifiers tended to exert themselves less than low identifiers during Trial 2 if they were told they were above average, whereas if told they were below average, high identifiers exerted themselves slightly more than low identifiers. Results provide evidence that descriptive norm messages can improve people's performance on physically demanding tasks, and indicate that descriptive physical activity norms may be more influential when the norm reference group is subjectively meaningful. Opportunities to fruitfully deploy norm messages in applied contexts are discussed.

Should We Trust Perceived Effort for Loading Control and Resistance Exercise Prescription After ACL Reconstruction?

CONTEXT

The rating of perceived effort (RPE) is a common method used in clinical practice for monitoring, loading control, and resistance training prescription during rehabilitation after rupture and anterior cruciate ligament reconstruction (ACLR). It is suggested that the RPE results from the integration of the afferent feedback and corollary discharge in the motor and somatosensory cortex, and from the activation of brain areas related to emotions, affect, memory, and pain (eg, posterior cingulate cortex, precuneus, and prefrontal cortex). Recent studies have shown that rupture and ACLR induce neural adaptations in the brain commonly associated with the RPE. Therefore, we hypothesize that RPE could be affected because of neural adaptations induced by rupture and ACLR.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

RPE could be directly altered by changes in the activation of motor cortex, posterior cingulate cortex, and prefrontal cortex. These neural adaptations may be induced by indirect mechanisms, such as the afferent feedback deficit, pain, and fear of movement (kinesiophobia) that patients may feel after rupture and ACLR.

CONCLUSION

Using only RPE for monitoring, loading control, and resistance training prescription in patients who had undergone ACLR could lead to under- or overdosing resistance exercise, and therefore, impair the rehabilitation process.

STRENGTH-OF-RECOMMENDATION TAXONOMY

3C.

An Updated Narrative Review on Ergometric Systems Applied to Date in Assessing Divers' Fitness

Many recreational divers suffer medical conditions, potentially jeopardizing their safety. To scale down risks, medical examinations are mandatory and overwhelmingly performed using bicycle ergometry, which overlooks some important aspects of diving. Searching ergometric systems that better address the underwater environment, a systematic literature search was conducted using the keywords 'diving', 'fitness', 'ergometry', and 'exertion'. All presented alternative systems found convincingly describe a greatly reduced underwater physical performance. Thus, if a diver's workload in air should already be limited, he/she will suffer early from fatigue, risking a diving incident. How to assess fitness? Performance diagnostics in sports is always specific for a modality or movement. Therefore, professional scuba divers should be tested when fin-swimming underwater. For the vast number of recreational divers, the current screening can likely not be replaced. However, to prevent accidents, divers need to understand and be able to improve factors that limit their physical performance underwater. Other systems, presented here, will continue to be important tools in underwater research.

Not All About the Effort? A Comparison of Playing Intensities During Winning and Losing Game Quarters in Basketball

PURPOSE

To compare peak and average intensities encountered during winning and losing game quarters in basketball players.

METHODS

Eight semiprofessional male basketball players (age = 23.1 [3.8] y) were monitored during all games (N = 18) over 1 competitive season. The average intensities attained in each quarter were determined using microsensors and heart-rate monitors to derive relative values (per minute) for the following variables: PlayerLoad, frequency of high-intensity and total accelerations, decelerations, changes of direction, jumps, and total inertial movement analysis events combined, as well as modified summated-heart-rate-zones workload. The peak intensities reached in each quarter were determined using microsensors and reported as PlayerLoad per minute over 15-second, 30-second, 1-minute, 2-minute, 3-minute, 4-minute, and 5-minute sample durations. Linear mixed models and effect sizes were used to compare intensity variables between winning and losing game quarters.

RESULTS

Nonsignificant (P > .05), unclear-small differences were evident between winning and losing game quarters in all variables.

CONCLUSIONS

During winning and losing game quarters, peak and average intensities were similar. Consequently, factors other than the intensity of effort applied during games may underpin team success in individual game quarters and therefore warrant further investigation.

Effects of Sarcopenia on Ventilatory Behavior and the Multidimensional Nature of Dyspnea in Patients With Chronic Obstructive Pulmonary Disease

OBJECTIVES

This study tested the hypothesis that sarcopenia, a common extrapulmonary feature of chronic obstructive pulmonary disease (COPD), can affect ventilatory behavior, and worsen the multidimensional nature of dyspnea in patients with COPD.

DESIGN

Cross-sectional survey study.

SETTING

and Participants: Stable outpatients with COPD encountered in general practice and respiratory clinic.

METHOD

Sarcopenia was diagnosed according to an appendicular skeletal muscle mass index based on measurements of electrical impedance and handgrip strength. Exertional dyspnea was tested using a 3-minute Step Test and a 6-minute Walk Test. The dimensions of dyspnea were assessed by a multidimensional dyspnea profile.

RESULTS

Of 60 stable patients with COPD, 16 met the criteria for sarcopenia. During the 3-minute Step Test, minute ventilation as a proportion of exercise time, tidal volume as a proportion of inspiratory capacity, the change in inspiratory capacity, and ventilation as a proportion of maximal voluntary ventilation did not differ between patients with and without sarcopenia. Patients with sarcopenia exhibited lower evolution of tidal volume, higher evolution of respiratory frequency versus ventilation and breathing discomfort on the 3-minute Step Test, as well as increased physical breathing effort on the 6-minute Walk Test, compared with those without sarcopenia. In a multivariable model adjusted using inverse probability weighting, sarcopenia was independently associated with breathing discomfort during the 3-minute Step Test and physical breathing effort during the 6-minute Walk Test.

CONCLUSIONS AND IMPLICATIONS

Sarcopenia may be associated with shallow breathing and diverse sensory and affective components of exertional dyspnea in patients with COPD. The study indicates that improvement of the rapid breathing pattern may offer unique ways to alleviate dyspnea in older patients with COPD and sarcopenia.

Exerted running results in altered impact mechanics and footstrike patterns following gait retraining

Exertion may alter running mechanics and increase injury risk. Effects of exertion following gait-retraining are unknown.

OBJECTIVES

To determine how exertion effects load rates, footstrike, and cadence in runners following a transition to forefoot strike (FFS) or increased cadence (CAD) gait-retraining.

METHODS

33 (9 M, 24 F) healthy rearfoot strike runners were randomized into CAD or FFS groups. All runners received strengthening exercises and gait-retraining. 3D kinetic and kinematic motion analysis with instrumented treadmill at self-selected speed was performed at baseline & 1-week post-intervention, including an exerted run. Exertion was ≥17 on Borg's Rating of Perceived Exertion scale or voluntary termination of running.

RESULTS

Within group comparisons between fresh and exerted running: Cadence not affected in either group. Foot angle at contact became less plantarflexed in FFS (-2.2°, ±0.4) and was unchanged in CAD. Both groups increased vertical average load rate (FFS +16.9%, CAD +13.6%). CAD increased vertical stiffness (+8.6 kN/m). FFS reduced ankle excursion (1.8°). (p ≤ 0.05 for all values listed).

CONCLUSION

Both FFS and CAD exhibited increased load rates with exertion. Variables that may have increased load rates were different for each group. CAD runners had increased vertical stiffness while FFS runners had reduced plantarflexion at contact and reduced ankle dorsiflexion excursion.

How long after maximal physical exertion should baseline computerized neurocognitive testing and symptom assessment be administered?

Objective: Prior research suggests maximal physical exertion (MPE) may negatively affect the reliability and validity of computerized neurocognitive testing (CNT); the purpose of this study was to identify aclinically relevant recovery interval following MPE for the administration of baseline CNT.Design: Random-crossover.Participants: Thirty (M = 21.87 ± 2.29 y), moderately-active,healthy participants, without history of ADHD, learning disabilities, psychological disorders or concussion (within the last six months).Intervention: Participants completed four randomly ordered experimental trials. Except for the control trial, CNT was administered following MPE with assigned recovery intervals [Immediate, 10-minutes,or 20-minutes]. Aseries of repeated measures analysis of variance (ANOVAs) were performed on CNT composite and total symptom scores.Results: Total symptom scores were significantly greater (p < .01) at the immediate, 10-minute,and 20-minuterecovery intervals compared to the control trial. Processing speed was significantly faster at the 20-minuterecovery interval compared to the control trials. Visual memory, verbal memory, or reaction time did not differ across recovery intervals.Conclusions: Clinicians should wait more than 20 minutes before assessing baseline concussion symptoms following about of MPE.

Exercise Intensity May Not Moderate the Acute Effects of Functional Circuit Training on Cognitive Function: A Randomized Crossover Trial

Functional circuit training (FCT) has been demonstrated to acutely enhance cognitive performance (CP). However, the moderators of this observation are unknown. This study aimed to elucidate the role of exercise intensity. According to an a priori sample size calculation, n = 24 healthy participants (26 ± 3 years, 13 females), in randomized order, performed a single 15-min bout of FCT with low (20-39% of the heart rate reserve/HRR), moderate (40-59% HRR) or high intensity (maximal effort). Immediately pre- and post-workout, CP was measured by use of the Digit Span test, Stroop test and Trail Making test. Non-parametric data analyses did not reveal significant differences between conditions (p > 0.05) although parameter-free 95% confidence intervals showed pre-post improvements in some outcomes at moderate and high intensity only. The effort level does not seem to be a major effect modifier regarding short-term increases in CP following HCT in young active adults.

Acute metabolic responses after continuous or interval exercise in post-menopausal women with overweight or obesity

This pilot study compared the effects of acute high-intensity intermittent exercise (HIIE) and moderate-intensity continuous exercise (MICE) on post-exercise VO₂ , fat utilization, and 24-hours energy balance to understand the mechanism of higher fat mass reduction observed after high-intensity interval training in post-menopausal women with overweight/obesity. 12 fasted women (59.5 ± 5.8 years; BMI: 28.9 ± 3.9 kg·m^-2 ) completed three isoenergetic cycling exercise sessions in a counterbalanced, randomized order: (a) MICE [35 minutes at 60%-65% of peak heart rate, HR_max ], (b) HIIE 1 [60 × (8-s cycling-12-s recovery) at 80%-90% of HR_max ], and (c) HIIE 2 [10 × 1min at 80%-90% of HR_max  - 1-min recovery]. Then, VO₂ and fat utilization measured at rest and during the 2 hours post-exercise, enjoyment, perceived exertion, and appetite recorded during the session and energy intake (EI) and energy expenditure (EE) assessed over the next 24 hours were compared for the three modalities. Overall, fat utilization increased after exercise. No modality effect or time-modality interaction was observed concerning VO₂ and fat oxidation rate during the 2 hours post-exercise. The two exercise modalities did not induce specific EI and EE adaptations, but perceived appetite scores at 1 hour post-exercise were lower after HIIE 1 and HIIE 2 than MICE. Perceived exertion was higher during HIIE 1 and HIIE 2 than MICE, but enjoyment did not differ among modalities. The acute HIIE responses did not allow explaining the greater fat mass loss observed after regular high-intensity interval training in post-menopausal women with overweight/obesity. More studies are needed to understand the mechanisms involved in such adaptations.

Effect of Physical Fatigue Elicited by Continuous and Intermittent Exercise on Motor Imagery Ability

Purpose: The ability to perform motor imagery (MI) might be impaired by the physical fatigue elicited during training. Interestingly, there is also theoretical support for a more limited influence of fatigue in the existing literature. Method: We evaluated MI ability before and after two exercise protocols: (i) a continuous exercise of 20 min performed on a cycle ergometer at 80% of the secondary ventilatory threshold (Continuous exercise), and (ii) an intermittent exercise of 20 min involving sprints at maximal intensity performed with regular intervals (Intermittent exercise). MI ability evaluations were performed using validated behavioral (mental chronometry) and psychometric (subjective reports) methods. MI ability evaluations included mental rehearsal of a motor sequence which involved the main effectors of the exercise protocols (walking), and mental rehearsal of a motor task which did not involve the main somatic effectors of the exercise protocols (pointing movements with the upper limbs). Results: Mental chronometry showed that MI ability was degraded only after Intermittent exercise, while self-report measures of MI vividness revealed that MI ability was primarily impaired during MI of the walking task. Conclusions: Present results suggest that Intermittent exercise engaging anaerobic processes of energy expenditure, but not Continuous exercise engaging aerobic processes of energy expenditure, impaired MI ability. Findings are discussed in relation to the internal models theory of motor simulation, specifically changes in current state of the motor system under the fatigued state-affecting motor predictions. Present findings may contribute to successful applications of MI training in sports and rehabilitation.

Effects of exercise on symptoms, vestibular/ocular motor screening and postural stability in a college-aged sample

Aim:

To examine the effects of maximal exercise on symptoms, vestibular/ocular motor screening (VOMS) and postural stability.

Methodology:

A total of 17 college-aged individuals completed a symptom scale, VOMS and the modified Clinical Test for Sensory Interaction and Balance (m-CTSIB), followed by a graded maximal exercise treadmill test. Assessments were repeated post exercise, 20 and 40 min post-exercise.

Results:

Significant increases in total symptoms, symptom severity scores and m-CTSIB scores from baseline to immediate post exercise were reported. Following 20-min recovery, improvements were noted on symptoms, visual motion sensitivity on VOMS and m-CTSIB.

Conclusion:

Symptoms and postural stability are influenced by exercise and following 20 min of rest, returned to baseline, indicating that a period of 20 min following a suspected concussion may be needed to negate exercise effects.

Baseline concussion testing is often completed by athletes in a rested state, prior to beginning their respective sports season. However, concussions are often sustained while the athlete has undergone physical exertion and is in a fatigued state. Therefore, it may be inaccurate to compare fatigue-state sideline assessments with resting-state baselines. The purpose of this study was to compare the effects of pre- and post-exercise performance on common concussion assessment tools. Worse performance was noted between pre- and immediately post-exercise on these tools. A duration of 20 min after exercise, performance returned to pretest levels, indicating that clinicians should wait at least 20 min before conducting a sideline examination after a sustained concussion, to cancel out the effects of exercise.

Positive Affective and Enjoyment Responses to Four High-Intensity Interval Exercise Protocols

Several variables can be manipulated to compose high-intensity interval exercise (HIIE) protocols, and these different combinations may evoke different psychological responses (affect, enjoyment, mood, and perceived exertion). This study investigated psychological responses during four HIIE protocols. Following anthropometric measurements and two maximal exercise tests, 23 physically inactive adults (11 males [M_age = 25.6, SD = 4.8 years; M_{body mass} = 68.5, SD = 12.2 kg; M_height = 1.72, SD = 0.08 m] and 12 females [M_age = 25.0, SD = 3.5 years; M_{body mass} = 57.2, SD = 8.7 kg; M_height = 1.59, SD = 0.06 m]) performed four different types of HIIE on different days: (a) Long-interval HIIE (HIIE_L-10 × 60 seconds:60 seconds), (b) Short-interval HIIE (HIIE_S-2 blocks of 10 × 30 seconds:30 seconds with 120 seconds between blocks), (c) Repeated Sprint Training (19 × 6 seconds all out:40 seconds), and (d) Sprint Interval Training (4 × 30 seconds all-out efforts: 240 seconds). We used a final session to assess participants' HIIE preference. We recorded participant reports of affect, mood, and perceived exertion throughout protocols, and we recorded enjoyment after exercise session. Perceived exertion significantly increased across all HIIE protocols (p < .001), with higher values in the first quartile during Sprint Interval Training versus HIIE_L (p = .033). Affective response presented higher values pre-exercise and at the first quartile compared with all other moments (p < .001). Tension (p < .001) and depression (p = .013) decreased from pre- to post-exercise in all experimental conditions. At pre-exercise, female participants were tenser than males (p = .018), though males presented higher pre-exercise vigor scores than females (p = .023). Vigor increased over time for females (p = .022). Enjoyment did not vary between sexes or protocols. Participants expressed a higher preference for Repeated Sprint Training. HIIE protocols promoted positive psychological responses for physically inactive young adults, and exercise designs may modulate psychological responses.

Physical Load and Referees' Decision-Making in Sports Games: A Scoping Review

Referees in sports games have a high level of responsibility as they have to make correct and appropriate decisions at any point during a match. Regarding referees' decision-making (RDM) as a perceptual-cognitive process, evidence suggests that physical load might reduce cognitive performance and thus might reduce RDM performance as well. In consideration of increasing game dynamics, referees have to cope with high physical load, but they have to make correct and appropriate decisions further on. Here, we review the current state of research on the relationship between physical load and RDM. A scoping review was performed, in accordance with the PRISMA guidelines, using the following databases: Scopus, PubMed, Web of Science (all databases), SURF and SPONET (both with an English and German search). Only primary studies written in English or German that investigated the relationship between physical load and RDM in sports games were included. Eleven studies included in the review investigated six physical parameters and RDM: match period, velocity, blood lactate, running time, heart rate, distance covered. Most findings of the studies showed no relationship between physical load and RDM (n = 18). Thirteen findings suggest a negative relationship and three findings indicate a positive relationship between physical load and RDM. Results of the scoping review show contradictory evidence across and within investigated different physical parameters. As RDM consists of multi-factorial components, it is recommended to conduct systematic research programs - field as well as experimental studies - to resolve the missing control of potential confounding variables and to consider the difference of internal and external load.

Pulmonary Embolism Can Be Nauseous: A Case Report and Review of D-Dimer Use in Pediatric Oncology Patients

BACKGROUND

Pulmonary embolism (PE) is a very common presentation in the emergency department (ED). Despite being life-threatening, PE is preventable if diagnosed and managed early, especially in high-risk patients like pediatric oncology patients. A negative d-dimer has a high negative predictive value and can rule out PE in low-risk patients; however, it does not lower post-test probability enough and should be coupled with further diagnostics in high-risk patients.

CASE REPORT

We describe the case of a 14-year-old girl known to have acute lymphoblastic leukemia and presented to the ED with persistent nausea and vomiting only, which was exacerbated by exertion. She had previously presented to the ED 1 week earlier for the same complaint, with a nonrevealing physical examination. At that time, the patient was worked up for nausea and vomiting and received symptomatic treatment. An electrocardiogram (ECG) during that presentation showed normal sinus rhythm. During this presentation, ECG showed new ST segment depressions from V1 to V6 in addition to an S1Q3T3 pattern. This, coupled with the exacerbation of her initial symptoms, triggered further investigations. Computed tomography angiography (CTA) of the chest was performed and showed a right lower lobe segmental pulmonary artery embolus. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case highlights the importance of having a high level of suspicion for PE, especially in pediatric oncology patients and specifically in hematologic malignancies. Although our patient's presentation, examination, and laboratory results were not concerning initially, CTA of the chest showed a PE. We are addressing this particular topic to increase the awareness of emergency physicians of cases like this, as PE can have an unusual presentation and missing such a diagnosis can be fatal.

Psychological Responses to High-Intensity Interval Training: A Comparison of Graded Walking and Ungraded Running at Equivalent Metabolic Loads

High-intensity interval training (HIIT) is highly beneficial for health and fitness and is well tolerated. Treadmill-based HIIT normally includes running interspersed with walking. The purpose of this study was to compare ungraded running and graded walking HIIT on perceived exertion, affective valence, and enjoyment. Thirty-four active, healthy adults completed maximal testing and two 20-min HIIT trials alternating between 85% of VO2peak and a comfortable walking speed. Affective valence, enjoyment, and perceived exertion, both overall (ratings of perceived exertion [RPE]-O) and legs only (RPE-L), were measured. RPE-O and affective valence were similar between HIIT trials (p > .05), RPE-L was higher for walk HIIT (p < .05), and enjoyment was higher for run HIIT (p < .05). Findings indicate that both walk and run HIIT produce exertion, affective, and enjoyment responses that are positive and possibly supportive of exercise behavior. Walk HIIT may be desirable for individuals who are unable or do not want to run.

The Limits of Cognitive Reappraisal: Changing Pain Valence, but not Persistence, during a Resistance Exercise Task

Physiological discomfort is commonly cited as a barrier for initiating and persisting with exercise. Although individuals may think of physiological discomfort as determined by physical sensations, it can also be influenced by cognitive and emotional factors. We explored the impacts of interpreting the purpose of pain as a sign of muscle building (helpful) vs. a sign of muscle tearing and possible injury (harmful) and tested the effect of cognitive reappraisals, or shifting interpretations of pain, on exercise persistence and the subjective experience of discomfort during exercise. Seventy-eight participants were randomized to listen to voice recordings that framed exercise-related pain as helpful vs. harmful before participating in a standard muscular endurance test using the YMCA protocol. Although the two experimental groups did not differ in the overall number of resistance training repetitions achieved, participants who were asked to think about the benefits (rather than the negative consequences) of pain reported less negative pain valence during exercise. Thus, the experience of pain was influenced by appraisals of the meaning of pain, but differences in pain valence did not impact exercise persistence. Theoretical implications and applications for affect-based exercise interventions are discussed.

Twelve cases of exertional rhabdomyolysis in college football players from the same institution over a 23-year span: a descriptive study

BACKGROUND

Rhabdomyolysis is a syndrome characterized by muscle necrosis that leads to release of the intracellular contents of muscle cells into the systemic circulation. Rhabdomyolysis due to overexertion is an uncommon but well-known severe complication of strenuous activity. Exertional rhabdomyolysis (ER) is typically described in weight lifters and military recruits undergoing basic training. Few cases have been reported in football players without known predisposing risk factors. We report our experience with this condition in college football players in a single institution.

MATERIALS AND METHODS

College football players hospitalized for heat illness complicated by rhabdomyolysis were identified over a 23-year period. Clinical and laboratory findings were collected. Clinical course was recorded.

RESULTS

Twelve patients were identified. All were Black males. One had sickle cell trait. BMI averaged 33 kg/m² (range 23-45 kg/m²). Peak creatine phosphokinase (CPK) averaged 14,850 IU/L (range 1,021-109,616 IU/L). Serum creatinine averaged 1.9 mg/dl (range 1.2-3.1 mg/dl). Ten of twelve cases occurred in August. All responded to intravenous hydration with normalization of CPK and renal function. All returned to football.

CONCLUSIONS

ER is a serious complication of strenuous physical activity that can threaten renal function. ER tends to occur in August, which coincides with the start of football practice when athletes are more likely to be detrained. The condition can occur in Black athletes in the absence of sickle cell trait. ER carries a good prognosis when recognized early and treated adequately.

Excessive sedentary time during in-patient stroke rehabilitation

Background and Purpose Previous research suggests that patients receiving inpatient stroke rehabilitation are sedentary although there is little data to confirm this supposition within the Canadian healthcare system. The purpose of this cross-sectional study was to observe two weeks of inpatient rehabilitation in a tertiary stroke center to determine patients' activity levels and sedentary time. Methods Heart rate (HR) and accelerometer data were measured using an Actiheart monitor for seven consecutive days, 24 h/day, on the second week and the last week of admission. Participants or their proxies completed a daily logbook. Metabolic equivalent (MET) values were calculated and time with MET < 1.5 was considered sedentary. The relationship between patient factors (disability, mood, and social support) and activity levels and sedentary time were analyzed. Results Participants (n = 19; 12 males) spent 10 h sleeping and 4 h resting each day, with 86.9% of their waking hours sedentary. They received on average 8.5 task-specific therapy sessions; substantially lower than the 15 h/week recommended in best practice guidelines. During therapy, 61.6% of physical therapy and 76.8% of occupational therapy was spent sedentary. Participants increased their HR about 15 beats from baseline during physical therapy and 8 beats during occupational therapy. There was no relationship between sedentary time or activity levels and patient factors. Discussion Despite calls for highly intensive stroke rehabilitation, there was excessive sedentary time and therapy sessions were less frequent and of lower intensity than recommended levels. Conclusions In this sample of people attending inpatient stroke rehabilitation, institutional structure of rehabilitation rather than patient-related factors contributed to sedentary time.

Acute responses to structured aerobic and resistance exercise in women with gestational diabetes mellitus

Research on the acute responses to exercise in pregnancy is scarce, especially for women affected by gestational diabetes mellitus (GDM). The aim of this study was to investigate responses to a single bout of exercise performed multiple times throughout the pregnancy in women diagnosed with GDM. Data from 18 pregnant women (aged: 32.8 ± 3.8) diagnosed with GDM, treated with diet only, were analyzed. Participants' pre-pregnancy body mass index was 24.4 ± 4.9 kg/m² , 50% of them were nulliparous, and 50% of the sample regularly exercised before the pregnancy. The exercise intervention consisted of an individual structured aerobic and resistance exercise program performed twice per week from the time of diagnosis until at least the 36th week of pregnancy. The exercise program included 20 minutes of aerobic exercise, 20-25 minutes of resistance exercise, and 10 minutes of cool down. Maternal heart rate, systolic and diastolic blood pressure, temperature and fetal heart rate were measured at every exercise session, along with blood glucose on 3 occasions. In total, 365 exercise sessions were analyzed (85 in the second trimester and 280 in the third trimester), on average 20.3 ± 7.7 per participant. Heart rate and fetal heart rate were elevated during both the aerobic and resistance parts of the exercise session (P < .01) in comparison with the baseline while systolic and diastolic blood pressure did not change in the total sample. There was a slight elevation in tympanic membrane temperature during the aerobic part of the session (P < .01). All parameters returned to baseline levels by the end of the session. Glucose levels dropped from the baseline, from 4.7 ± 0.6 to 3.9 ± 0.4 mmol/L (P < .01). There were no differences in responses to exercise between the second and third trimesters, nor between pre-pregnancy exercisers and non-exercisers. The combination of aerobic and resistance exercise for women diagnosed with GDM does not have harmful short-term effects if performed according to guidelines. Likewise, exercise can be considered useful for controlling hyperglycemia in pregnancy for women affected by GDM.

Macrophage Targeted Cellular Carriers for Effective Delivery of Anti-Tubercular Drugs

BACKGROUND

Newly developed vaccine VPM1002 confers paradigm swing in the prophylactic treatment of tuberculosis (TB). Multi-drug resistant and latent TB in adults as well as in underprivileged patients is instigating menace over world population if the host is immune-compromised.

METHODS

One third of the world's population is infected with TB. Recently it is estimated around 9.6 million people around the world became sick with TB disease. There were 1.5 million TB-related deaths worldwide. Therefore with the advent in biotechnology and Nano engineering, newly adapted survival molecular mechanism of Mycobacterium tuberculosis, new targets receptors on alveolar macrophages must be explored out for eradication of TB from the globe. Macrophage acts as a reservoir of phagocytic receptors to execute diverse physiological functions as well as to perform defense mechanism.

RESULTS

Advances in novel carriers open new era for the treatment of tuberculosis which remains a very substantial global health encumbrance. Different binding receptors especially mannose, folate and scavenger receptors are attractive platform for internalization of therapeutics in alveolar macrophage. Nano-carriers and nano-devices designed after the acquaintance of receptor composition and functioning affords site specific targeting of biodegradable and biocompatible drug delivery systems for the treatment of tuberculosis offering complete cure and patient compliance.

CONCLUSION

This chapter encompasses recent studies on nanocarriers and new treatment strategies for tuberculosis. In spite of the budding benefits of nano carriers, many limitations still remain to be overcome such as poor oral stability, instability in circulation, inadequate tissue distribution as well as toxicity to normal cells.

11β-hydroxysteroid dehydrogenase type-II activity is affected by grapefruit juice and intense muscular work

OBJECTIVE

The enzymatic activity of 11β-hydroxysteroid dehydrogenase-2 (11β-HSD2) is key to protecting mineral corticoid receptors from cortisol and has been implicated in blood pressure regulation. Grapefruit juice (GFJ) and acidity are thought to inhibit this enzyme in vitro. This study examines the effect of GFJ and intense exercise on 11β-HSD2 enzyme activity in vivo.

SUBJECTS AND METHODS

Eighteen subjects ingested GFJ or apple juice (CON) on separate days prior to reporting to the laboratory in a randomized order. Saliva (Sal) samples were obtained at baseline, 15 and 45 minutes post-treadmill stress test; Sal cortisone (E) and cortisol (F) levels were determined, and the Sal cortisone:cortisol (E:F) ratio was used as an index of 11β-HSD2 enzyme activity at rest and after intense muscular work.

RESULTS

GFJ treatment decreased baseline 11β-HSD2 enzyme activity (44%) and Sal-E (28%) compared to CON (both, p < 0.05). Sal-E (r = 0.61, p < 0.05) and Sal-F (r = 0.66, p < 0.05) were correlated with diastolic blood pressure (DBP) in GFJ-treated individuals. Treadmill stress significantly increased Sal-E and Sal-F but did not alter 11β-HSD2 enzyme activity regardless of treatment. When treatments were examined separately, CON 11β-HSD2 enzyme activity decreased by 36% (p < 0.05) from baseline to 15 post-treadmill exercise.

CONCLUSION

Our findings suggest that GFJ and intense muscular work decrease 11β-HSD-2 activity independently, and no additive effect was noted. The association between DBP and the levels of Sal-F and Sal-E during the GFJ trial should be interpreted cautiously and warrants further investigation.

The effects of introducing Tabata interval training and stability exercises to school children as a school-based intervention program

Background Physical activities during leisure time as well as school hours have changed over the past few years, with adolescents being less physically active and adopting a sedentary lifestyle. Objective The overall objective of this mixed-methods study was to evaluate the feasibility of introducing a 4-min Tabata interval training into a lower secondary school context. A further aim was to evaluate the possible effects on: coordination, balance, and strength. Methods The study was conducted as an intervention study with a mixed-method approach. Forty-three children, aged 7-9 years, participated in the intervention group. Additionally, 13 children were recruited as a control group. The intervention itself was delivered by the teachers and was performed for 4-min every day in a classroom setting. All participants performed physical tests before and after the intervention period to evaluate the Tabata training. After the completion of the 6-week Tabata interval training, the four teachers were interviewed. Results The push-ups (p = 0.004), kneeling push-ups (p = 0.03), and standing long jump (p = 0.01) improved in the intervention group after 6 weeks. No differences were observed between the genders. The teachers experienced that it worked well to integrate the Tabata interval training in the classroom setting. Conclusion After 6 weeks, a school-based Tabata intervention program improved physical performance. The teachers saw no obstacles in including the Tabata intervention program in a classroom setting and pointed out several positive aspects such as an increased energy level and development in the children's movement patterns.

Comfort and exertion while using filtering facepiece respirators with exhalation valve and an active venting system among male military personnel

INTRODUCTION

This study aimed to determine if disposable filtering facepiece respirators (FFRs) that come with an exhalation valve (EV) and a novel active venting system (AVS) provided greater perceived comfort and exertion when compared to standard N95 FFRs without these features among male military personnel performing prolonged essential outdoor duties.

METHODS

We used a randomised open-label controlled crossover study design to compare three FFR options: (a) standard FFR; (b) FFR with EV; and (c) FFR with EV+AVS. Male military personnel aged between 18 and 20 years completed a questionnaire at the start of outdoor duty (baseline), after two hours of standardised non-strenuous outdoor duty and after 12 hours of duty divided into two-hour work-rest cycles. Participants rated the degree of discomfort, exertion and symptoms using a five-point Likert scale. The association between outcomes and types of FFR was assessed using a multivariate ordered probit mixed-effects model.

RESULTS

For a majority of the symptoms, study participants gave FFR with EV and FFR EV+AVS significantly better scores than standard FFR. Both FFR with EV and FFR with EV+AVS had significantly less discomfort (FFR with EV+AVS: 91.1%; FFR with EV: 57.6%) and exertion (FFR with EV+AVS: 83.5%; FFR with EV: 34.4%) than standard FFR. FFR with EV+AVS also had significantly better scores for exertion (53.4%) and comfort (39.4%) when compared to FFR with EV.

CONCLUSION

Usage of FFR with EV+AVS resulted in significantly reduced symptoms, discomfort and exertion when compared to FFR with EV and standard FFR.

Ischemic preconditioning does not improve peak exercise capacity at sea level or simulated high altitude in trained male cyclists

Ischemic preconditioning (IPC) may improve blood flow and oxygen delivery to tissues, including skeletal muscle, and has the potential to improve intense aerobic exercise performance, especially that which results in arterial hypoxemia. The aim of the study was to determine the effects of IPC of the legs on peak exercise capacity (W(peak)), submaximal and peak cardiovascular hemodynamics, and peripheral capillary oxygen saturation (SpO2) in trained males at sea level (SL) and simulated high altitude (HA; 13.3% FIO2, ∼ 3650 m). Fifteen highly trained male cyclists and triathletes completed 2 W(peak) tests (SL and HA) and 4 experimental exercise trials (10 min at 55% altitude-specific W(peak) then increasing by 30 W every 2 min until exhaustion) with and without IPC. HA resulted in significant arterial hypoxemia during exercise compared with SL (73% ± 6% vs. 93% ± 4% SpO2, p < 0.001) that was associated with 21% lower W(peak) values. IPC did not significantly improve W(peak) at SL or HA. Additionally, IPC failed to improve cardiovascular hemodynamics or SpO2 during submaximal exercise or at W(peak). In conclusion, IPC performed 45 min prior to exercise does not improve W(peak) or systemic oxygen delivery during submaximal or peak exercise at SL or HA. Future studies must examine the influence of IPC on local factors, such as working limb blood flow, oxygen delivery, and arteriovenous oxygen difference as well as whether the effectiveness of IPC is altered by the volume of muscle made ischemic, the timing prior to exercise, and high altitude acclimatization.

Risk of cardiac disease and observations on lack of potential predictors by clinical history among children presenting for cardiac evaluation of mid-exertional syncope

OBJECTIVE

This study aimed to evaluate the incidence of cardiac disorders among children with mid-exertional syncope evaluated by a paediatric cardiologist, determine how often a diagnosis was not established, and define potential predictors to differentiate cardiac from non-cardiac causes. Study design We carried out a single-centre, retrospective review of children who presented for cardiac evaluation due to a history of exertional syncope between 1999 and 2012. Inclusion criteria included the following: (1) age ⩽18 years; (2) mid-exertional syncope; (3) electrocardiogram, echocardiogram and an exercise stress test, electrophysiology study, or tilt test, with exception of long QT, which did not require additional testing; and (4) evaluation by a paediatric cardiologist. Mid-exertional syncope was defined as loss of consciousness in the midst of active physical activity. Patients with peri-exertional syncope immediately surrounding but not during active physical exertion were excluded.

RESULTS

A total of 60 patients met the criteria for mid-exertional syncope; 32 (53%) were diagnosed with cardiac syncope and 28 with non-cardiac syncope. A majority of cardiac patients were diagnosed with an electrical myopathy, the most common being Long QT syndrome. In nearly half of the patients, a diagnosis could not be established or syncope was felt to be vasovagal in nature. Neither the type of exertional activity nor the symptoms or lack of symptoms occurring before, immediately preceding, and after the syncopal event differentiated those with or without a cardiac diagnosis.

CONCLUSIONS

Children with mid-exertional syncope are at risk for cardiac disease and warrant evaluation. Reported symptoms may not differentiate benign causes from life-threatening disease.

Heart Failure Impairs Muscle Blood Flow and Endurance Exercise Tolerance in COPD

Heart failure, a prevalent and disabling co-morbidity of COPD, may impair cardiac output and muscle blood flow thereby contributing to exercise intolerance. To investigate the role of impaired central and peripheral hemodynamics in limiting exercise tolerance in COPD-heart failure overlap, cycle ergometer exercise tests at 20% and 80% peak work rate were performed by overlap (FEV1 = 56.9 ± 15.9% predicted, ejection fraction = 32.5 ± 6.9%; N = 16), FEV1-matched COPD (N = 16), ejection fraction-matched heart failure patients (N = 15) and controls (N = 12). Differences (Δ) in cardiac output (impedance cardiography) and vastus lateralis blood flow (indocyanine green) and deoxygenation (near-infrared spectroscopy) between work rates were expressed relative to concurrent changes in muscle metabolic demands (ΔO2 uptake). Overlap patients had approximately 30% lower endurance exercise tolerance than COPD and heart failure (p < 0.05). ΔBlood flow was closely proportional to Δcardiac output in all groups (r = 0.89-0.98; p < 0.01). Overlap showed the largest impairments in Δcardiac output/ΔO2 uptake and Δblood flow/ΔO2 uptake (p < 0.05). Systemic arterial oxygenation, however, was preserved in overlap compared to COPD. Blunted limb perfusion was related to greater muscle deoxygenation and lactate concentration in overlap (r = 0.78 and r = 0.73, respectively; p < 0.05). ΔBlood flow/ΔO2 uptake was related to time to exercise intolerance only in overlap and heart failure (p < 0.01). In conclusion, COPD and heart failure add to decrease exercising cardiac output and skeletal muscle perfusion to a greater extent than that expected by heart failure alone. Treatment strategies that increase muscle O2 delivery and/or decrease O2 demand may be particularly helpful to improve exercise tolerance in COPD patients presenting heart failure as co-morbidity.

Simulated Firefighting Task Performance and Physiology Under Very Hot Conditions

PURPOSE

To assess the impact of very hot (45°C) conditions on the performance of, and physiological responses to, a simulated firefighting manual-handling task compared to the same work in a temperate environment (18°C).

METHODS

Ten male volunteer firefighters performed a 3-h protocol in both 18°C (CON) and 45°C (VH). Participants intermittently performed 12 × 1-min bouts of raking, 6 × 8-min bouts of low-intensity stepping, and 6 × 20-min rest periods. The area cleared during the raking task determined work performance. Core temperature, skin temperature, and heart rate were measured continuously. Participants also periodically rated their perceived exertion (RPE) and thermal sensation. Firefighters consumed water ad libitum. Urine specific gravity (USG) and changes in body mass determined hydration status.

RESULTS

Firefighters raked 19% less debris during the VH condition. Core and skin temperature were 0.99 ± 0.20 and 5.45 ± 0.53°C higher, respectively, during the VH trial, and heart rate was 14-36 beats.min(-1) higher in the VH trial. Firefighters consumed 2950 ± 1034 mL of water in the VH condition, compared to 1290 ± 525 in the CON trial. Sweat losses were higher in the VH (1886 ± 474 mL) compared to the CON trial (462 ± 392 mL), though both groups were hydrated upon protocol completion (USG < 1.020). Participants' average RPE was higher in the VH (15.6 ± 0.9) compared to the CON trial (12.6 ± 0.9). Similarly, the firefighers' thermal sensation scores were significantly higher in the VH (6.4 ± 0.5) compared to the CON trial (4.4 ± 0.4).

CONCLUSIONS

Despite the decreased work output and aggressive fluid replacement observed in the VH trial, firefighters' experienced increases in thermal stress, and exertion. Fire agencies should prioritize the health and safety of fire personnel in very hot temperatures, and consider the impact of reduced productivity on fire suppression efforts.

Effects of Low-Dose Aspirin Therapy on Thermoregulation in Firefighters

BACKGROUND

Heart attack is the most common cause of line-of-duty death in the fire service. Daily aspirin therapy is a preventative measure used to reduce the morbidity of heart attacks but may decrease the ability to dissipate heat by reducing skin blood flow.

METHODS

In this double-blind, placebo-controlled, crossover study, firefighters were randomized to receive 14 days of therapy (81-mg aspirin or placebo) before performing treadmill exercise in thermal-protective clothing in a hot room [38.8 ± 2.1°C, 24.9 ± 9.1% relative humidity (RH)]. Three weeks without therapy was provided before crossing to the other arm. Firefighters completed a baseline skin blood-flow assessment via laser Doppler flowmetry; skin was heated to 44°C to achieve maximal cutaneous vasodilation. Skin blood flow was measured before and after exercise in a hot room, and at 0 minutes, 10 minutes, 20 minutes, and 30 minutes of recovery under temperature conditions (25.3 ± 1.2°C, 40.3 ± 13.7% RH). Platelet clotting time was assessed before drug administration, and before and after exercise.

RESULTS

Fifteen firefighters completed the study. Aspirin increased clotting time before and after exercise compared with placebo (p = 0.003). There were no differences in absolute skin blood flow between groups (p = 0.35). Following exercise, cutaneous vascular conductance (CVC) was 85 ± 42% of maximum in the aspirin and 76 ± 37% in the placebo groups. The percentage of maximal CVC did not differ by treatment before or after recovery. Neither maximal core body temperature nor heart rate responses to exercise differed between trials.

CONCLUSION

There were no differences in skin blood flow during uncompensable heat stress following exercise after aspirin or placebo therapy.

The effect of hip belt use and load placement in a backpack on postural stability and perceived exertion: a within-subjects trial

The purpose of this study was to assess the effects of hip belt use and load placement in a backpack on perceived exertion and postural stability. Thirty participants were instructed to stand on a force plate and walk along a designated route under five conditions: unloaded, high-load placement, low-load placement, hip belt on and hip belt off. The average velocity and sway area from the force plate were measured. Participants also rated their perceived stability and exertion. Compared to the unloaded condition, all loaded conditions significantly increased average velocity, sway area, perceived stability and exertion. Hip belt use did not affect average velocity and sway area; however, participants reported higher levels of stability and lower levels of exertion with hip belt use. Load placement did not affect average velocity, sway area, perceived stability or exertion. This study showed that wearing a backpack loaded to 20% of body weight reduced postural stability, while manipulation of load placement in a backpack did not affect subjective and objective measures of postural stability. Also, hip belt use only improved subjective measures of postural stability.

Ventilation Distribution Heterogeneity at Rest as a Marker of Exercise Impairment in Mild-to-Advanced COPD

The difference between total lung capacity (TLC) by body plethysmography and alveolar volume (VA) from the single-breath lung diffusing capacity measurement provides an index of ventilation distribution inequalities in COPD. The relevance of these abnormalities to dyspnea and exercise intolerance across the continuum of disease severity remains unknown. Two-hundred and seventy-six COPD patients distributed across GOLD grades 1 to 4 and 67 healthy controls were evaluated. The "poorly communicating fraction" (PCF) of the TLC was estimated as the ratio (%) of TLC to VA. Healthy subjects showed significantly lower PCF values compared to GOLD grades 1 to 4 (10 ± 3% vs. 17 ± 8% vs. 27 ± 10% vs. 37 ± 10% vs. 56 ± 11%, respectively; p < 0.05). Pulmonary gas exchange impairment, mechanical ventilatory constraints and ventilation-corrected dyspnea scores worsened across PCF tertiles (p < 0.05). Of note, GOLD grades 1 and 2 patients with the highest PCF values had pronounced exercise ventilatory inefficiency and dyspnea as a limiting symptom. In fact, dyspnea was a significant contributor to exercise limitation only in those with "moderate" or "extensive" PCF (p < 0.05). A receiver operating characteristics curve analysis revealed that PCF was a better predictor of severely reduced maximal exercise capacity than traditional pulmonary function indexes including FEV1 (area under the curve (95% confidence interval) = 0.85 (0.81-0.89), best cutoff = 33.4%; p < 0.01). In conclusion, PCF is a readily available functional marker of gas exchange and mechanical abnormalities relevant to dyspnea and exercise intolerance across the COPD grades.

Evaluating the Nintendo Wii for assessing return to activity readiness in youth with mild traumatic brain injury

Adolescents with mild traumatic brain injuries (MTBI) are at substantial risk for repeat injury if they return to activity too soon. Post-concussion symptoms and impaired balance are two factors that limit return to activity. Post-injury assessments that challenge activity tolerance and balance skills are needed to ensure readiness to return to activity. This cross-sectional study evaluated the Nintendo Wii as a measure of exertion (heart rate [HR], respiration rate [RR], and caloric expenditure) and balance testing for youth with MTBI in a clinical setting. Twenty-four youth with MTBI, ages 9-18, played six Wii games. The Bruininks-Oseretsky Test of Motor Proficiency 2nd edition (BOT-2) and the Community Balance and Mobility Scale (CBM) were used as balance indicators. The Wii Fit Running game demonstrated the highest caloric expenditure and HR (p = .010). Frequency counts of balance loss during Wii game play did not correlate with performance on the BOT-2 or the CBM. Type, number, and time since injury were predictive of balance performance on the CBM (p = .008). Findings provide preliminary evidence for the use of the Wii as an exertion challenge to evaluate tolerance for exercise post-concussion. Frequency count of balance loss during Wii game play, however, was not a valid measure of balance impairment post-MTBI.

The Influence of Exercise Environment and Gender on Mood and Exertion

This study examined the influence of exercise environment and gender on post-exercise mood and exertion. College student participants (55 females, 49 males) were instructed to pedal a stationary bike at a moderate pace for 20 minutes. Participants were randomly assigned to one of three laboratory conditions: (1) exercising in front of a mirror and posters showing ideal fit body types (i.e., celebrity male and female personal trainers), (2) exercising in front of a mirror only, or (3) a control condition in which participants exercised without a mirror or posters. The Activation-Deactivation Adjective Check List (AD-ACL), measuring exercise-induced mood states, was administered both before and after exercise. Average bike speed throughout the exercise session measured exertion. Mirrors and posters of ideally fit celebrities did interact with gender on post-exercise tension in that women felt most tense after exercising in front of the mirror and posters while men were most tense after exercising in front of the mirror only. Exercise exertion was also impacted by experimental condition such that participants rode significantly faster in the mirror and posters condition. There was no significant interaction of gender and condition on exercise exertion, but women pedaled fastest in the mirror and poster condition relative to the other conditions. Results suggest that exercise exertion and tension reduction are partially a by-product of gender and exercise environment.

Migraine with aura in the locker room: three case reports

It is well known that physical activity can aggravate the intensity of the headache, but the pathophysiological relationship between exertion and aura is still unknown. Anecdotal reports describe episodes of migraine preceded by head trauma and visual symptoms, migraine prodrome symptoms after unusually strenuous running with no subsequent head pain or recurrent attacks of hemiplegic migraine induced only by exertion. We describe the cases of three young men with recurrent episodes of migraine with aura occurring in the locker room shortly after a football match. Since the symptoms could mimic important pathologies in approximately 10% of these of headaches, it was mandatory to exclude a secondary form of headache in these patients. Several theories exist regarding the cause of primary exertional headache, but the pathogenesis of migraine triggered by physical activity has still not been identified. The present International Classification of Headache Disorders does not mention sport/exercise-induced migraine with aura episodes as primary headache. Since there are many cases described in the literature of migraine with aura triggered only by exercise, it may be helpful to specify, in the typical aura with migraine headache comments, that in some cases it can be exclusively triggered by sport/exercise.

Discomfort and exertion associated with prolonged wear of respiratory protection in a health care setting

The nature of discomfort and level of exertion associated with wearing respiratory protection in the health care workplace are not well understood. Although a few studies have assessed these topics in a laboratory setting, little is known about the magnitude of discomfort and the level of exertion experienced by workers while they deliver health care to patients for prolonged periods. The purpose of this study was to determine the magnitude of discomfort and level of exertion experienced by health care workers while wearing respiratory protection for periods up to 8 hr when performing their typical occupational duties. This project was a multiple cross-over field trial of 27 health care workers, aged 24-65, performing their typical, hospital-based occupational duties. Each participant served as his/her own control and wore one of seven respirators or a medical mask for 8 hr (or as long as tolerable) with interposed doffing periods every 2 hr. Self-perceived discomfort and exertion were quantified before each doffing: self-perceived level of discomfort using a visual analog scale, and self-perceived level of exertion using a Borg scale. Overall, and as would be expected, discomfort increased over time with continual respirator use over an 8-hr period. Interestingly, exertion increased only marginally over the same time period. The relatively low level of exertion associated with eight respiratory protective devices, including models commonly used in the U.S. health care workplace, is not likely to substantially influence workers' tolerability or occupational productivity. However, the magnitude of discomfort does appear to increase significantly over time with prolonged wear. These results suggest that respirator-related discomfort, but not exertion, negatively influences respirator tolerance over prolonged periods. Discomfort may also interfere with the occupational duties of workers.

Unexpected sudden death of a 19-year-old female with congenital single coronary artery ostium during exertion

Coronary artery anomalies are associated often with myocardial ischemia or sudden cardiac death. A 19-year-old woman who participated in an exertive game lost consciousness upon one such exertion. She was taken to a hospital where she died on the same day. An autopsy revealed that she had bifurcated coronary arteries, which arose from one coronary ostium in the left sinus of Valsalva. The right coronary artery arose from the left sinus and traveled between the aorta and the pulmonary trunk. The heart as well as the cardiac conduction system depended exclusively on the single coronary artery ostium for oxygenated blood supply, and the unbalanced blood distribution on her exertion probably led to sudden cardiac death. The case highlights the medicolegal importance of unexpected sudden cardiac death related to an anomalous origin of the coronary arteries.