Neural Adaptations to Resistive Exercise

Kinetic Compensations due to Chronic Ankle Instability during Landing and Jumping

INTRODUCTION

Skeletal muscles absorb and transfer kinetic energy during landing and jumping, which are common requirements of various forms of physical activity. Chronic ankle instability (CAI) is associated with impaired neuromuscular control and dynamic stability of the lower extremity. Little is known regarding an intralimb, lower-extremity joint coordination of kinetics during landing and jumping for CAI patients. We investigated the effect of CAI on lower-extremity joint stiffness and kinetic and energetic patterns across the ground contact phase of landing and jumping.

METHODS

One hundred CAI patients and 100 matched able-bodied controls performed five trials of a landing and jumping task (a maximal vertical forward jump, landing on a force plate with the test leg only, and immediate lateral jump toward the contralateral side). Functional analyses of variance and independent t-tests were used to evaluate between-group differences for lower-extremity net internal joint moment, power, and stiffness throughout the entire ground contact phase of landing and jumping.

RESULTS

Relative to the control group, the CAI group revealed (i) reduced plantarflexion and knee extension and increased hip extension moments; (ii) reduced ankle and knee eccentric and concentric power, and increased hip eccentric and concentric power, and (iii) reduced ankle and knee joint stiffness and increased hip joint stiffness during the task.

CONCLUSIONS

CAI patients seemed to use a hip-dominant strategy by increasing the hip extension moment, stiffness, and eccentric and concentric power during landing and jumping. This apparent compensation may be due to decreased capabilities to produce sufficient joint moment, stiffness, and power at the ankle and knee. These differences might have injury risk and performance implications.

Rate of Improvement of Pain and Function in Mid-Portion Achilles Tendinopathy with Loading Protocols: A Systematic Review and Longitudinal Meta-Analysis

BACKGROUND

Mid-portion Achilles tendinopathy is prevalent within both the athletic and non-athletic populations and loading protocols for Achilles tendinopathy are effective over time, though the rate of symptom change throughout rehabilitation is unknown.

OBJECTIVE

The objective of this study was to determine the rate of change in pain and function over time in patients while completing a loading protocol for mid-portion Achilles tendinopathy.

METHODS

A systematic review and longitudinal meta-analysis was conducted as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The databases PubMed, CINAHL (Ovid) and CINAHL (EBSCO) were searched for articles published from inception until 31 July, 2017. Our search focused on clinical trials and cohort studies examining changes in pain and function when completing a loading protocol for mid-portion Achilles tendinopathy. The primary outcome measure assessing pain and function was the Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire.

RESULTS

A total of 31 separate cohorts (24 studies) were eligible, with follow-up ranging from 2 weeks to 6 months. The data were pooled to create the mean (standard deviation) of change from baseline at each time point. The data demonstrated an improvement in pain and function as early as 2 weeks that appeared to peak at 12 weeks with a mean (standard deviation) of 21.11 (6.61) points of change on the VISA-A.

CONCLUSION

The improvement in pain and function during rehabilitation suggests future research should be directed toward investigating contributing mechanisms as tendon structure on imaging does not change within 2 weeks and muscular hypertrophy is not seen for at least 4 weeks following the inception of a loading protocol. Systematic Review Registry: PROSPERO registration number: CRD42017062737 ( https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=62737 ).

Time course of interlimb strength transfer after unilateral handgrip training

"Cross-education" is the increase in strength or functional performance of an untrained limb after unilateral training. A major limitation for clinical translation from unilateral injury includes knowledge on the minimum time for the emergence of crossed effects. Therefore, the primary purpose was to characterize the time course of bilateral strength changes during both "traditional" ( n = 11) and "daily" ( n = 8) unilateral handgrip training in neurologically intact participants. Traditional training included five sets of five maximal voluntary handgrip contractions 3 times/wk for 6 wk whereas daily training included the same number of sessions and contractions but over 18 consecutive days. Three pre- and one posttest session evaluated strength, muscle activation, and reflex excitability bilaterally. Time course information was assessed by recording handgrip force for every contraction in the trained limb and from a single contraction on every third training session in the untrained limb. Six weeks of traditional training increased handgrip strength in the trained limb after the 9th session whereas the untrained limb was stronger after the 12th session. This was accompanied by increased peak muscle activation and bilateral alterations in Hoffmann reflex excitability. Daily training revealed a similar number of sessions (15) were required to induce significant strength gains in the untrained limb (7.8% compared with 12.5%) in approximately half the duration of traditional training. Therefore, minimizing rest days may improve the efficiency of unilateral training when the trained limb is not the focus. Establishing a "dose" for the time course of adaptation to strength training is paramount for effective translation to rehabilitative interventions. NEW & NOTEWORTHY Unilateral handgrip training using a "traditional" protocol (3 times/wk; 6 wk) increased strength bilaterally after 9 (trained arm) and 12 (untrained arm) sessions. "Daily" training (18 consecutive days) increased strength in the untrained limb in a similar number of training sessions, which was accomplished in approximately half the time. Within clinical populations when the focus is on the untrained limb, reducing rest days may optimize the recovery of strength.

Eccentric cross-exercise after anterior cruciate ligament reconstruction: Novel case series to enhance neuroplasticity

OBJECTIVES

Substantial changes in neural function are historically present after anterior cruciate ligament reconstruction (ACLR), and are not rectified with traditional rehabilitation. Cross-exercise is a potential means to enhance neural excitability and improve recovery after ACLR. Hence our purpose, was to detail changes in brain activation, neural excitability and patient-reported outcomes in a cohort that completed an 8-week quadriceps-focused eccentric cross-exercise training program immediately following ACLR.

DESIGN

Case series.

SETTING

University.

PARTICPANTS

Five patients participated in an 8-week (24-session) eccentric cross-exercise intervention after ACLR.

MAIN OUTCOME MEASURES

Brain activation, neural activity and patient-reported outcomes were evaluated within 2 weeks post-ACLR and again at 10-weeks post-ACLR after the intervention. Each cross-exercise session consisted of 4 sets of 10 isokinetic eccentric contractions at 60 deg/sec with the noninvolved limb.

RESULTS

Following the intervention, patients demonstrated a facilitated spinal reflexive and muscle activity response from the motor cortex during a time when these measures are known to be depressed. Patients also demonstrated a reduce dependence on frontal cortex activity to generate quadriceps contractions. Further patients reported significant reductions in pain and symptoms and greater knee function.

CONCLUSIONS

Eccentric cross-exercise after ACLR helps to facilitate positive adaptations in neural function and patient reported outcomes.

Can upper limb taping or exercises improve hand function, writing speed and self-perception of performance in adolescent school children?

BACKGROUND

The majority of students spend time in writing, which is a prime performance measure in examinations. Enhancement in handwriting should benefit students to attain better academic performance.

OBJECTIVE

To assess the effectiveness of taping and exercises on hand function, writing speed, self-perception of writing and to compare these techniques.

METHODS

A randomized control trial was conducted using cluster sampling in adolescent children across four schools in an urban city. A 4-week intervention study was conducted on 123 students divided into taping, exercise and control groups. Outcome measures were grip strength, pinch strength, 12-min writing speed test and the Writer Self-Perception Scale (WSPS). For intra-group analysis, a paired t-test was used for parametric values and the Wilcoxon signed rank test was used for non-parametric values. For inter-group analysis, one-way analysis of variance (ANOVA) for parametric values and the Kruskal-Wallis test for non-parametric values was used.

RESULTS

The taping group showed a significant improvement in grip strength (1.79 kg; p = 0.00), pinch strength [1.67 lb (757.4 g); p = 0.00] and writing speed (39.77 words/12 min; p = 0.00). The exercise group showed significant improvement in grip strength (2.09 kg; p = 0.00), pinch strength (1.28 lb; p = 0.00), writing speed (28.38 words/12 min; p = 0.00). In the control group, there was a significant increase in pinch strength (1.023 lb; p = 0.01) and writing speed (12.94 words/12 min; p = 0.02). Inter-group analysis showed significant difference in writing speed (p = 0.002) and grip strength (p = 0.00). There was no significant difference in perception (p = 0.071).

CONCLUSION

Taping and exercise are equally effective for enhancement of hand function, writing speed and self-perception in adolescent school children.

Determining the potential sites of neural adaptation to cross-education: implications for the cross-education of muscle strength

Cross-education describes the strength gain in the opposite, untrained limb following a unilateral strength training program. Since its discovery in 1894, several studies now confirm the existence of cross-education in contexts that involve voluntary dynamic contractions, eccentric contraction, electrical stimulation, whole-body vibration and, more recently, following mirror feedback training. Although many aspects of cross-education have been established, the mediating neural mechanisms remain unclear. Overall, the findings of this review show that the neural adaptations to cross-education of muscle strength most likely represent a continuum of change within the central nervous system that involves both structural and functional changes within cortical motor and non-motor regions. Such changes are likely to be the result of more subtle changes along the entire neuroaxis which include, increased corticospinal excitability, reduced cortical inhibition, reduced interhemispheric inhibition, changes in voluntary activation and new regions of cortical activation. However, there is a need to widen the breadth of research by employing several neurophysiological techniques (together) to better understand the potential mechanisms mediating cross-education. This fundamental step is required in order to better prescribe targeted and effective guidelines for the clinical practice of cross-education. There is a need to determine whether similar cortical responses also occur in clinical populations where, perhaps, the benefits of cross-education could be best observed.

Effect of Lower-Body Resistance Training on Upper-Body Strength Adaptation in Trained Men

Bartolomei, S, Hoffman, JR, Stout, JR, and Merni, F. Effect of lower-body resistance training on upper-body strength adaptation in trained men. J Strength Cond Res 32(1): 13-18, 2018-The aim of this study was to examine the effect of 2 different lower-body strength training schemes on upper-body adaptations to resistance training. Twenty resistance-trained men (4.25 ± 1.6 years of experience) were randomly assigned to either a high intensity (HI; n = 9; age = 24.9 ± 2.9 years; body mass = 88.7 ± 17.2 kg; height = 177.0 ± 5.6 cm) or a mixed high volume and HI resistance training program (MP; n = 11; age = 26.0 ± 4.7 years; body mass = 82.8 ± 9.1 kg; height = 177.54 ± 5.9 cm). High-intensity group followed a HI training for both upper and lower body (4-5 reps at 88%-90% of 1 repetition maximum (1RM)), whereas the MP group performed high-volume training sessions focused on muscle hypertrophy for lower body (10-12 reps at 65%-70% of 1-RM) and a HI protocol for the upper body. Maximal strength and power testing occurred before and after the 6-week training program. Analysis of covariance was used to compare performance measures between the groups. Greater increases in MP groups compared with HI groups were observed for bench press 1RM (p = 0.007), bench press power at 50% of 1RM (p = 0.011), and for arm muscle area (p = 0.046). Significant difference between the 2 groups at posttest were also observed for fat mass (p = 0.009). Results indicated that training programs focused on lower-body muscle hypertrophy and maximal strength for upper body can stimulate greater strength and power gains in the upper body compared with HI resistance training programs for both the upper and lower body.

Effect of muscle strengthening exercise and time since onset in patients with amyotrophic lateral sclerosis: A 2-patient case series study

Exercise for patients with amyotrophic lateral sclerosis (ALS) can be expected to improve function at the early stage of disease, but improvement cannot be expected at the late stage. However, no report has investigated the correlation between the effect of exercise and time since onset. This study examined the relevance between the effect of muscle strengthening exercise and time since onset in patients with ALS.This study is a retrospective nonconsecutive case series study at a single university hospital. We included 2 patients with ALS who were admitted twice. Case 1 was a 60-year-old man with the bulbar type. He was hospitalized 10 months (ALS functional rating scale-revised, 42 points) and 1 year and 8 months (33 points) after onset. Case 2 was a 52-year-old man with the lower limb type. He was hospitalized 1 year and 3 months (44 points) and 1 year and 8 months (33 points) after onset. Physical therapy was implemented daily on weekdays for approximately 30 minutes. The intervention period was 2 weeks. Lower limb muscle strengthening exercises were mainly performed and exercise intensity was adjusted to a modified Borg Scale score of 5 (lower limbs). The study investigated knee extension muscle strength (KEMS) by using a hand-held dynamometer and Functional Ambulation Categories (FAC) at the start and end of physical therapy during each hospitalization.KEMS improved during the initial hospitalization in both patients, and FAC improved in Case 2; neither KEMS nor FAC improved during rehospitalization in either patient. In Case 1, KEMS was maintained for 10 months.The current results suggest that the positive effect of muscle strengthening exercise is greater at the early stage and may be maintained in patients with bulbar type ALS. In addition, improvement can be achieved approximately 1 year after onset and in patients with an ALSFRS-R score of 40 points or more. Therefore, it is necessary to initiate and continue exercise earlier after onset.

Ischemic conditioning increases strength and volitional activation of paretic muscle in chronic stroke: a pilot study

Ischemic conditioning (IC) on the arm or leg has emerged as an intervention to improve strength and performance in healthy populations, but the effects on neurological populations are unknown. The purpose of this study was to quantify the effects of a single session of IC on knee extensor strength and muscle activation in chronic stroke survivors. Maximal knee extensor torque measurements and surface EMG were quantified in 10 chronic stroke survivors (>1 yr poststroke) with hemiparesis before and after a single session of IC or sham on the paretic leg. IC consisted of 5 min of compression with a proximal thigh cuff (inflation pressure = 225 mmHg for IC or 25 mmHg for sham) followed by 5 min of rest. This was repeated five times. Maximal knee extensor strength, EMG magnitude, and motor unit firing behavior were measured before and immediately after IC or sham. IC increased paretic leg strength by 10.6 ± 8.5 Nm, whereas no difference was observed in the sham group (change in sham = 1.3 ± 2.9 Nm, P = 0.001 IC vs. sham). IC-induced increases in strength were accompanied by a 31 ± 15% increase in the magnitude of muscle EMG during maximal contractions and a 5% decrease in motor unit recruitment thresholds during submaximal contractions. Individuals who had the most asymmetry in strength between their paretic and nonparetic legs had the largest increases in strength ( r² = 0.54). This study provides evidence that a single session of IC can increase strength through improved muscle activation in chronic stroke survivors. NEW & NOTEWORTHY Present rehabilitation strategies for chronic stroke survivors do not optimally activate paretic muscle, and this limits potential strength gains. Ischemic conditioning of a limb has emerged as an effective strategy to improve muscle performance in healthy individuals but has never been tested in neurological populations. In this study, we show that ischemic conditioning on the paretic leg of chronic stroke survivors can increase leg strength and muscle activation while reducing motor unit recruitment thresholds.

The effects of functional and traditional strength training on different strength parameters of elderly women: a randomized and controlled trial

BACKGROUND

Physical exercise is the main strategy for improving physical fitness in elderly population. However, it is not clear which training method lead to greater adaptations on maximal dynamic strength, muscle power, muscle endurance and isometric strength in this population. Thus, our aim was to compare the effects of functional and traditional training on these variables in the elderly.

METHODS

This study lasted twelve weeks, where 44 elderly women were randomly divided into three groups: functional training (FT; N.=18), traditional training (TT; N.=15), and control group (CG; N.=11). Maximal dynamic strength and muscle power tests were performed in pushing (Chest Press), pulling (Seated Row), and squatting (Leg Press 45°) actions. In addition, isometric strength with hand grip test (HG) and isometric dead lift test (ID) and muscle endurance with 30-s chair stand (CS) and 30-s arm curl (AC) tests were used.

RESULTS

Both experimental groups improved significantly in strength (FT: Chest Press 24.9%, Leg Press 45° 38.4%, Seated Row 21.6%; TT: Chest Press 27.6%, Leg Press 45° 40.9%, Seated Row 24.5%), power (FT: Chest Press 13.6%, Leg Press 45° 11.6%, Seated Row 13.6%; TT: Chest Press 18.2%, Leg Press 45° 9.8%, Seated Row 19.2%) isometric strength (FT: HG=14.7%, ID=13.6%; TT: HG=19.1%), and endurance (TF: CS=19.6%, AC=23.8%; TT: AC=15.5%) with P≤0.05, except TT in ID (4.4%) and SL (4.6%). There was no difference between experimental groups; however, both experimental groups were statistically superior to CG.

CONCLUSIONS

Both training protocols were equally effective in improving different strength manifestations in the elderly.

Effects of different intensities of resistance training with equated volume load on muscle strength and hypertrophy

The present study investigated the effects of different intensities of resistance training (RT) on elbow flexion and leg press one-repetition maximum (1RM) and muscle cross-sectional area (CSA). Thirty men volunteered to participate in an RT programme, performed twice a week for 12 weeks. The study employed a within-subject design, in which one leg and arm trained at 20% 1RM (G20) and the contralateral limb was randomly assigned to one of the three conditions: 40% (G40); 60% (G60), and 80% 1RM (G80). The G20 started RT session with three sets to failure. After G20 training, the number of sets was adjusted for the other contralateral limb conditions with volume-matched. CSA and 1RM were assessed at pre, post-6 weeks, and post-12 weeks. There was time effect for CSA for the vastus lateralis (VL) (8.9%, 20.5%, 20.4%, and 19.5%) and elbow flexors (EF) (11.4%, 25.3%, 25.1%, and 25%) in G20, G40, G60, and G80, respectively (p > .05). G80 showed higher CSA than G20 for VL (19.5% vs. 8.9%) and EF (25% vs. 11.4%) at post-12 weeks (p < .05). There was time effect for elbow flexion and unilateral leg press strength for all groups post-12 weeks (p < .05). However, the magnitude of increase was higher in G60 and G80. In conclusion, when low to high intensities of RT are performed with volume-matched, all intensities were effective for increasing muscle strength and size; however, 20% 1RM was suboptimal in this regard, and only the heavier RT intensity (80% 1RM) was shown superior for increasing strength and CSA compared to low intensities.

Effects of Community-Based Exercise in Adults With Severe Burns: A Randomized Controlled Trial

OBJECTIVE

To investigate the efficacy of community-based exercise programs in the rehabilitation of adult patients with burns compared with standard of care (SOC).

DESIGN

Randomized controlled trial, with 2:1 randomization.

SETTING

Assessments were performed in a hospital setting. The intervention was performed in a community setting.

PARTICIPANTS

Adult patients (N=45) with ≥30% total body surface area burns were randomized to participate in a community-based exercise program (n=31) or SOC (n=14). Patient sampling was consecutive and referred.

INTERVENTIONS

The community-based exercise program consisted of 12 weeks of exercise with a community-based trainer after hospital discharge. The SOC group did not receive exercise training.

MAIN OUTCOME MEASURES

Change in lean body mass index, peak torque, and peak oxygen consumption from discharge to 12 weeks postdischarge, presented as mean ± SE.

RESULTS

The community-based exercise program group showed a significant increase in peak oxygen consumption compared with SOC (community-based exercise program: Δ=7.723±1.522mL/kg/min, P=.0006; SOC: Δ=2.200±1.150mL/kg/min, P=.0765; community-based exercise program vs SOC, P=.0236). The community-based exercise program group exhibited a significant within group increase in lean body mass index (Δ=1.107±0.431kg/m², P=.0003; SOC: Δ=1.323±0.873kg/m², P=.2808). Both groups showed significant within-group increases in peak torque (community-based exercise program: Δ=35.645±7.566Nm, P=.0003; SOC: Δ=34.717±11.029Nm, P=.0082). No significant differences were noted between the 2 groups for lean body mass index or peak torque.

CONCLUSIONS

Patients who participate in a community-based exercise program show significant improvements in cardiopulmonary fitness compared with SOC, supporting the use of a community-based exercise program as an alternative therapy to SOC in adults with severe burns.

Differential impact of tongue exercise on intrinsic lingual muscles

OBJECTIVES/HYPOTHESIS

Aging is associated with muscle fiber hypotrophy and decreased percentages of rapidly contracting myosin heavy chain (MyHC) type IIb muscle fibers. Tongue exercise programs used to treat dysphagia target age-related decline in tongue muscle function, but the impact of exercise on the intrinsic tongue muscles is unknown. We hypothesized that exercise would induce muscle fiber hypertrophy and increase the percentage of MyHC IIa fibers in the intrinsic tongue.

STUDY DESIGN

Animal model.

METHODS

Eight old and eight young-adult rats underwent 8 weeks of tongue exercise training, and 8 animals of each age group served as controls. Longitudinal, transverse, and verticalis muscle samples from the anterior, middle, and posterior regions of the tongue were sectioned and stained to determine muscle fiber diameter and MyHC composition.

RESULTS

MyHC fiber type distribution was altered by exercise, and the effects differed by muscle and region of the tongue. In the exercise groups, as compared to the control groups, the anterior transverse and middle superior longitudinal muscles had significantly reduced percentages of MyHC IIx positive fibers and higher percentages of rapidly contracting fatigable MyHC IIb positive muscle fibers, whereas the middle transverse and posterior longitudinal muscles had increased percentages of the less rapidly contracting and more fatigue-resistant MyHC IIa fibers. The impact of exercise did not differ with age, as there was no significant interaction between age and exercise. Tongue exercise had no significant effect on muscle fiber diameter.

CONCLUSIONS

The impact of exercise varied among the tongue muscles, which may indicate different functional contributions to the tongue exercise task.

LEVEL OF EVIDENCE

NA Laryngoscope, 128:2245-2251, 2018.

Transition Between the Timed up and Go Turn to Sit Subtasks: Is Timing Everything?

OBJECTIVE

The Timed Up and Go (TUG), one of the most widely used tests of mobility, has been validated and associated with adverse outcomes in the community, acute care, and nursing home setting. It is composed of several distinct subtasks; however, the temporal relationship when transitioning between subtasks has not been well-studied. We tested the hypothesis that longer transition durations between the final turn to the sitting subtasks are associated with worse motor and cognitive performance in older adults.

METHODS

A total of 1055 participants (80.33 ± 7.57 years, 76.96% female) performed the TUG while wearing a 3-dimensional inertial sensor on their lower back. We employed a series of linear regressions to examine the association of the duration between the turn and sitting subtasks with clinical characteristics including motor and cognitive functions.

RESULTS

Participants employed 2 different strategies when they transitioned from turning to sitting. (1) Distinct transition strategy: 816 participants (77.34%) first completed the turn before starting to sit. The average duration between these distinct subtasks (D-interval) was 715 ± 980 ms. (2) Overlapping transition strategy: 239 participants (22.65%) started to sit before completing the turn. The average overlap duration between these tasks (O-interval) was 237 ± 269 ms. Participants who employed the distinct transition strategy were slightly younger than those who employed the overlapping transition strategy (P ≤ .013). Higher D-intervals and O-intervals were associated with worse TUG performance (P ≤ .02), with poorer motor and cognitive function, [ie, worse parkinsonian gait (P ≤ .001), lower level of perceptual speed (P ≤ .03), and with worse mobility disability (P ≤ .001)]. A longer D-interval was associated with worse gait speed and bradykinesia (P ≤ .001), whereas a longer O-interval was associated with increased rigidity (P = .004).

CONCLUSIONS

Older adults apparently employ 2 different strategies when transitioning from turning to sitting. The instrumented TUG can characterize additional gait and balance aspects that cannot be derived from traditional TUG assessments. These new measures offer novel targets for intervention to decrease the burden of late-life gait impairment.

The Influence of Resistance Training Experience on the Between-Day Reliability of Commonly Used Strength Measures in Male Youth Athletes

Weakley, JJS, Till, K, Darrall-Jones, J, Roe, GAB, Phibbs, PJ, Read, DB, and Jones, BL. The influence of resistance training experience on the between-day reliability of commonly used strength measures in male youth athletes. J Strength Cond Res 31(7): 2005-2010, 2017-The purpose of this study was to determine the between-day reliability of commonly used strength measures in male youth athletes while considering resistance training experience. Data were collected on 25 male athletes over 2 testing sessions, with 72 hours rest between, for the 3 repetition maximum (3RM) front squat, chin-up, and bench press. Subjects were initially categorized by resistance training experience (inexperienced; 6-12 months, experienced; >2 years). The assessment of the between-day reliability (coefficient of variation [CV%]) showed that the front squat (experienced: 2.90%; inexperienced: 1.90%), chin-up (experienced: 1.70%; inexperienced: 1.90%), and bench press (experienced: 4.50%; inexperienced: 2.40%) were all reliable measures of strength in both groups. Comparison between groups for the error of measurement for each exercise showed trivial differences. When both groups were combined, the CV% for the front squat, bench press, and chin-up were 2.50, 1.80, and 3.70%, respectively. This study provides scientists and practitioners with the between-day reliability reference data to determine real and practical changes for strength in male youth athletes with different resistance training experience. Furthermore, this study demonstrates that 3RM front squat, chin-up, and bench press are reliable exercises to quantify strength in male youth athletes.

Treatment-based Classification System for Patients With Low Back Pain: The Movement Control Approach

We present the movement control approach as part of the treatment-based classification system. This approach proposes a movement control schema that clarifies that movement control is a product of the interplay among multiple biopsychosocial components. The schema illustrates that for movement to occur in a dynamically controlled fashion, the lumbar spine requires both local mobility and global stability. Local mobility means that the lumbar spine and its adjacent regions possess adequate nerve and joint(s) mobility and soft tissue compliance (ie, the malleability of tissue to undergo elastic deformation). Global stability means that the muscles of the lumbar spine and its adjacent regions can generate activation that is coordinated with various joint movements and incorporated into activities of daily living. Local mobility and global stability are housed within the bio-behavioral and socio-occupational factors that should be addressed during movement rehabilitation. This schema is converted into a practical physical examination to help the rehabilitation provider to construct a clinical rationale as to why the movement impairment(s) exist. The examination findings are used to guide treatment. We suggest a treatment prioritization that aims to consecutively address neural sensitivity, joint(s) and soft tissue mobility, motor control, and endurance. This prioritization enables rehabilitation providers to better plan the intervention according to each patient's needs. We emphasize that treatment for patients with low back pain is not a static process. Rather, the treatment is a fluid process that changes as the clinical status of the patient changes. This movement control approach is based on clinical experience and indirect evidence; further research is needed to support its clinical utility.

Effects of Different Combinations of Strength, Power, and Plyometric Training on the Physical Performance of Elite Young Soccer Players

The combination of strength (ST) and plyometric training (PT) has been shown to be effective for improving sport-specific performance. However, there is no consensus about the most effective way to combine these methods in the same training session to produce greater improvements in neuromuscular performance of soccer players. Thus, the purpose of this study was to compare the effects of different combinations of ST and PT sequences on strength, jump, speed, and agility capacities of elite young soccer players. Twenty-seven soccer players (age: 18.9 ± 0.6 years) participated in an 8-week resistance training program and were divided into 3 groups: complex training (CP) (ST before PT), traditional training (TD) (PT before ST), and contrast training (CT) (ST and PT performed alternately, set by set). The experimental design took place during the competitive period of the season. The ST composed of half-squat exercises performed at 60-80% of 1 repetition maximum (1RM); the PT composed of drop jump exercises executed in a range from 30 to 45 cm. After the experimental period, the maximum dynamic strength (half-squat 1RM) and vertical jump ability (countermovement jump height) increased similarly and significantly in the CP, TD, and CT (48.6, 46.3, and 53% and 13, 14.2, and 14.7%, respectively). Importantly, whereas the TD group presented a significant decrease in sprinting speed in 10 (7%) and 20 m (6%), the other groups did not show this response. Furthermore, no significant alterations were observed in agility performance in any experimental group. In conclusion, in young soccer players, different combinations and sequences of ST and PT sets result in similar performance improvements in muscle strength and jump ability. However, it is suggested that the use of the CP and CT methods is more indicated to maintain/maximize the sprint performance of these athletes.

Effects of exercise improves muscle strength and fat mass in patients with high fracture risk: A randomized control trial

BACKGROUND

The deterioration of the musculoskeletal system imposes significant impact on physical activity. Exercise is an important strategy which minimizes these changes. It is not clear which type of exercise provides better improvement on low physical performance, low muscle mass and low strength of sarcopenia. We aim to develop an integrated care (IC) model and compare its relative efficacy in limb fat free mass, muscle strength, and physical performance with low extremities exercise (LEE) in community dwelling older adults with high risk of fractures (Fracture Risk Assessment Tool (FRAX^®)) ≧3% for hip fracture, ≧20% for major osteoporotic fracture or 1-min osteoporosis risk test (≧1 point) or fall (≧2 falls in previous year).

METHODS

Patients were assigned randomized to participate in either IC or LEE group (n = 55 each) for 3 months. All participants received education including home-based exercise. The IC group consisted of different modalities of exercise while the LEE group performed machine-based low extremities exercise. Fat free mass, muscle strength, and physical performance were measured at their baseline and 3-months follow-up.

RESULTS

Mean age was 73.8 ± 7 years with 69.1% women. Entire cohort demonstrated significant increment in fat free mass, muscle strength (4 indicators) and physical performance (3 indicators). However, between group differences were not significant.

CONCLUSION

With regular supervise exercise; both groups are equally effective in decreasing fat mass and increasing physical performance, muscle mass and strength. However, the IC group required fewer resources and thus more financially feasible in a community setting.

High-Speed Cycling Intervention Improves Rate-Dependent Mobility in Older Adults

PURPOSE

The aim was to determine the feasibility of a 6-wk speed-based exercise program that could be used to initiate new exercise behaviors and to improve rapid movement in older adults approaching frailty.

METHODS

The intervention group included 14 older adults (3 males and 11 females; mean ± SD, age = 70 ± 7.6 yr, height = 1.6 ± 0.11 m, mass = 76.8 ± 12.0 kg, body mass index = 27.7 ± 4.7 kg·m). The control group included 12 older adults (6 males and 6 females; mean ± SD, age = 69.2 ± 6.9 yr, height = 1.7 ± 0.09 m, mass = 78.2 ± 10.9 kg, body mass index = 25.3 ± 2.7 kg·m). Subjects included active older adults, including regular exercisers, but none were engaged in sports or exercises with an emphasis on speed (e.g., cycling spin classes or tennis). Stationary recumbent cycling was selected to minimize fall risk, and low pedaling resistance reduced musculoskeletal and cardiovascular load. Two weekly 30-min exercise sessions consisted of interval training in which subjects pedaled at preferred cadence and performed ten 20-s fast cadence intervals separated by 40 s of active recovery at preferred cadence.

RESULTS

Significant group-time interactions (P < 0.05) supported a 2-s improvement in the timed up and go test and a 34% improvement in rapid isometric knee extension contractions in the exercise group but not in controls. Central neural adaptations are suggested because this lower extremity exercise program also elicited significant improvements in the untrained upper extremities of the exercise group (elbow extension rate of force development scaling factor and Nine-Hole Peg Test, P < 0.05).

CONCLUSION

These results demonstrate that a relatively low dose of speed-based exercise can improve neuromuscular function and tests of mobility in older adults. Such a program serves as a sensible precursor to subsequent, more vigorous training or as an adjunct to a program where a velocity emphasis is lacking.

Syngeneic B16F10 Melanoma Causes Cachexia and Impaired Skeletal Muscle Strength and Locomotor Activity in Mice

Muscle wasting has been emerging as one of the principal components of cancer cachexia, leading to progressive impairment of work capacity. Despite early stages melanomas rarely promotes weight loss, the appearance of metastatic and/or solid tumor melanoma can leads to cachexia development. Here, we investigated the B16F10 tumor-induced cachexia and its contribution to muscle strength and locomotor-like activity impairment. C57BL/6 mice were subcutaneously injected with 5 × 10⁴ B16F10 melanoma cells or PBS as a Sham negative control. Tumor growth was monitored during a period of 28 days. Compared to Sham mice, tumor group depicts a loss of skeletal muscle, as well as significantly reduced muscle grip strength and epididymal fat mass. This data are in agreement with mild to severe catabolic host response promoted by elevated serum tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and lactate dehydrogenase (LDH) activity. Tumor implantation has also compromised general locomotor activity and decreased exploratory behavior. Likewise, muscle loss, and elevated inflammatory interleukin were associated to muscle strength loss and locomotor activity impairment. In conclusion, our data demonstrated that subcutaneous B16F10 melanoma tumor-driven catabolic state in response to a pro-inflammatory environment that is associated with impaired skeletal muscle strength and decreased locomotor activity in tumor-bearing mice.

Using Virtual Reality to Transfer Motor Skill Knowledge from One Hand to Another

As far as acquiring motor skills is concerned, training by voluntary physical movement is superior to all other forms of training (e.g. training by observation or passive movement of trainee's hands by a robotic device). This obviously presents a major challenge in the rehabilitation of a paretic limb since voluntary control of physical movement is limited. Here, we describe a novel training scheme we have developed that has the potential to circumvent this major challenge. We exploited the voluntary control of one hand and provided real-time movement-based manipulated sensory feedback as if the other hand is moving. Visual manipulation through virtual reality (VR) was combined with a device that yokes left-hand fingers to passively follow right-hand voluntary finger movements. In healthy subjects, we demonstrate enhanced within-session performance gains of a limb in the absence of voluntary physical training. Results in healthy subjects suggest that training with the unique VR setup might also be beneficial for patients with upper limb hemiparesis by exploiting the voluntary control of their healthy hand to improve rehabilitation of their affected hand.

Gender, Success, and Drop-Out during a Resistance Exercise Program in Community Dwelling Old Adults

Background

Resistance exercise training can be effective against sarcopenia. We identified predictors of drop-out and compared physical outcomes between men and women after such training.

Methods

Subjects (N = 236, 73.7 ± 5.7 years) participated in a 12-week resistance exercise program. Outcome variables were measured at baseline and endpoint.

Results

Drop-out was 11.9% and not significantly different between genders. Drop-outs were significantly older and had poorer strength and physical function in comparison to completers. Anthropometrics, QoL, and cognitive function were not related to drop-out. According to multivariate analysis, gait speed and physical activity were the strongest predictors of drop-out. After the training, gains in lean mass or appendicular muscle were significantly higher in men than women; however relative gains in appendicular muscle as well as absolute improvements in strength and function were similar in men and women, respectively.

Conclusions

Participants who drop out are older, have poorer physical function, and are less physically active. Old women do not drop out more frequently than men and show meaningful improvements in relevant outcomes similar to men after such a training program. The trial is registered at the US National Library of Medicine (NCT01074879).

Muscle-bone interactions: movement in the field of mechano-humoral coupling of muscle and bone

Cyclical, mechanical loading of bone by skeletal muscle is widely recognized as a critical determinant of bone structure and mass. A growing body of evidence indicates that substances released from skeletal muscle into the bloodstream also regulate bone mass and metabolism. In this commentary, we discuss the status of research in the area of humoral regulation of bone mass by the skeletal muscle secretome, with an emphasis on the roles of myostatin, irisin, interleukin-6, and exosomes. The interplay between muscle, bone, and other modulators of bone mass, including circadian rhythm and sympathetic tone, is also discussed.

Effects of an Off-Axis Pivoting Elliptical Training Program on Gait Function in Persons With Spastic Cerebral Palsy: A Preliminary Study

This preliminary study examined the effects of off-axis elliptical training on reducing transverse-plane gait deviations and improving gait function in 8 individuals with cerebral palsy (CP) (15.5 ± 4.1 years) who completed an training program using a custom-made elliptical trainer that allows transverse-plane pivoting of the footplates during exercise. Lower-extremity off-axis control during elliptical exercise was evaluated by quantifying the root-mean-square and maximal angular displacement of the footplate pivoting angle. Lower-extremity pivoting strength was assessed. Gait function and balance were evaluated using 10-m walk test, 6-minute-walk test, and Pediatric Balance Scale. Toe-in angles during gait were quantified. Participants with CP demonstrated a significant decrease in the pivoting angle (root mean square and maximal angular displacement; effect size, 1.00-2.00) and increase in the lower-extremity pivoting strength (effect size = 0.91-1.09) after training. Reduced 10-m walk test time (11.9 ± 3.7 seconds vs. 10.8 ± 3.0 seconds; P = 0.004; effect size = 1.46), increased Pediatric Balance Scale score (43.6 ± 12.9 vs. 45.6 ± 10.8; P = 0.042; effect size = 0.79), and decreased toe-in angle (3.7 ± 10.5 degrees vs. 0.7 ± 11.7 degrees; P = 0.011; effect size = 1.22) were observed after training. We present an intervention to challenge lower-extremity off-axis control during a weight-bearing and functional activity for individuals with CP. Our preliminary findings suggest that this intervention was effective in enhancing off-axis control, gait function, and balance and reducing in-toeing gait in persons with CP.

Flexibility training and the repeated-bout effect: priming interventions prior to eccentric training of the knee flexors

Both the repeated-bout effect and increased flexibility have been linked to reduced muscle damage, fatigue, and strength loss after intense eccentric exercise. Our purpose was to compare the eccentric-training (ECC) response after first priming the muscles with either static flexibility training or a single intense bout of eccentric exercise. Twenty-five participants were randomly assigned to flexibility training (n = 8; 3×/week; 30 min/day), a single bout of intense eccentric exercise (n = 9), or no intervention (control; n = 8) during a 4-week priming phase, prior to completing a subsequent 4-week period of eccentric training of the knee flexors. Testing was completed prior to the priming phase, before ECC, during acute ECC (0 h, 24 h, and 48 h after bouts 1 and 4), and after ECC. Measures included muscle thickness (MT; via ultrasound); isometric, concentric, and eccentric strength; muscle power (dynamometer); electromyography; range of motion; optimal angle of peak torque; and soreness (visual analog scale). Flexibility training and single-bout groups had 47% less soreness at 48 h after the first bout of ECC compared with control (p < 0.05). The flexibility training group had 10% less soreness at 48 h after the fourth ECC bout compared with both the single-bout and control groups (p < 0.05). Isometric strength loss was attenuated for the flexibility training group (-9%) after the fourth ECC bout compared with control (-19%; p < 0.05). All groups had similar increases in strength, MT, and power after ECC (p < 0.05). Prior flexibility training may be more effective than a single session of eccentric exercise in reducing adverse symptoms during the acute stages of eccentric training; however, these benefits did not translate into greater performance after training.

Muscle activation during resistance training with no external load - effects of training status, movement velocity, dominance, and visual feedback

OBJECTIVES

To explore the acute effects of training status, movement velocity, dominance, and visual feedback on muscle activation and rating of perceived exertion (RPE) during resistance training with no external load (no-load resistance training; NLRT).

METHODS

Thirty-three men (17 untrained and 16 trained), performed elbow flexions in four NLRT sessions: 1) slow velocity with EMG visual feedback, 2) slow velocity without EMG visual feedback, 3) fast velocity with EMG feedback, and 4) fast velocity without EMG feedback. RPE was measured using the Borg Discomfort scale. EMG for the biceps and triceps were recorded for both arms.

RESULTS

EMG feedback had no influence on RPE. The peak and mean EMG values were not different for the biceps (93.8±11.5% and 50±13.1%) and triceps (93.7±23.9% and 49.6±16.2%). The results revealed a difference in the training status, with higher peak EMG for untrained than for trained participants (96.9±20% vs. 90.2±15.6%). However the values for mean EMG were not different between the untrained and trained (50.3±15.7% vs. 49.2±13.7%) participants. There was no difference in the peak (92.8±19% vs. 94.7±20.4%) and mean (49.8±15.0% vs. 49.7±14.5%) EMG values for the dominant and non-dominant sides. Peak EMG values were not different between faster and slower velocities (93.6±19.6% and 93.9±17.8%). However, mean EMG was higher for slower (50.5±14.4%) than for faster (48.5±15.4%) velocities. The peak and mean EMG during contractions with (93.3±17.5% and 49.5±14.1%) and without visual feedback (94.2±19.9% and 50±15.4%) were not significantly different.

CONCLUSION

NLRT produces high levels of muscle activation independent of training, status, dominance, movement velocity, and visual feedback.

Eccentric Exercise to Enhance Neuromuscular Control

Context:

Neuromuscular alterations are a major causal factor of primary and secondary injuries. Though injury prevention programs have experienced some success, rates of injuries have not declined, and after injury, individuals often return to activity with functionality below clinical recommendations. Considering alternative therapies to the conventional concentric exercise approach, such as one that can target neuromuscular injury risk and postinjury alterations, may provide for more effective injury prevention and rehabilitation protocols.

Evidence Acquisition:

Peer-reviewed sources available on the Web of Science and MEDLINE databases from 2000 through 2016 were gathered using searches associated with the keywords eccentric exercise, injury prevention, and neuromuscular control.

Hypothesis:

Eccentric exercise will reduce injury risk by targeting specific neural and morphologic alterations that precipitate neuromuscular dysfunction.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

Neuromuscular control is influenced by alterations in muscle morphology and neural activity. Eccentric exercise beneficially modifies several underlying factors of muscle morphology (fiber typing, cross-sectional area, working range, and pennation angle), and emerging evidence indicates that eccentric exercise is also beneficial to peripheral and central neural activity (alpha motorneuron recruitment/firing, sarcolemma activity, corticospinal excitability, and brain activation).

Conclusion:

There is mounting evidence that eccentric exercise is not only a therapeutic intervention influencing muscle morphology but also targets unique alterations in neuromuscular control, influencing injury risk.

Normalization of Temporal Aspects of Swallowing Physiology after the McNeill Dysphagia Therapy Program

Objectives

We examined the timing of physiological swallowing events in patients before and after completion of an exercise-based dysphagia intervention (McNeill Dysphagia Therapy Program; MDTP) and compared their performance to that of healthy volunteers.

Methods

Eight adults (mean age, 57.5 years) with chronic dysphagia (mean, 45 months) completed 3 weeks of the MDTP. Before and after the MDTP we measured lingual-palatal and pharyngeal manometric pressures during swallows of thin liquid, thick liquid, and pudding material in 5-mL volumes. Using the pressure peak of the pharyngoesophageal segment clearing wave as the anchor point, we measured the relative timing of pressure peaks from the anterior, middle, and posterior parts of the tongue and the manometric peaks from the base of the tongue, the hypopharynx, and the nadir of the pharyngoesophageal segment. We compared these results to identical measures obtained from 34 healthy adults (mean age, 44.0 years).

Results

The timing of physiological events before the MDTP was significantly slower than that of the group of healthy volunteers. The timing data from after the MDTP were not significantly different from those of the healthy group. The magnitude change was greatest for thin liquid.

Conclusions

Dysphagia therapy with the MDTP improves the timing of physiological events during swallowing. Temporal coordination of swallowing components after therapy approximates that of healthy adults, suggesting a normalization of swallow timing after the MDTP.

Greater Neural Adaptations following High- vs. Low-Load Resistance Training

We examined the neuromuscular adaptations following 3 and 6 weeks of 80 vs. 30% one repetition maximum (1RM) resistance training to failure in the leg extensors. Twenty-six men (age = 23.1 ± 4.7 years) were randomly assigned to a high- (80% 1RM; n = 13) or low-load (30% 1RM; n = 13) resistance training group and completed leg extension resistance training to failure 3 times per week for 6 weeks. Testing was completed at baseline, 3, and 6 weeks of training. During each testing session, ultrasound muscle thickness and echo intensity, 1RM strength, maximal voluntary isometric contraction (MVIC) strength, and contractile properties of the quadriceps femoris were measured. Percent voluntary activation (VA) and electromyographic (EMG) amplitude were measured during MVIC, and during randomly ordered isometric step muscle actions at 10–100% of baseline MVIC. There were similar increases in muscle thickness from Baseline to Week 3 and 6 in the 80 and 30% 1RM groups. However, both 1RM and MVIC strength increased from Baseline to Week 3 and 6 to a greater degree in the 80% than 30% 1RM group. VA during MVIC was also greater in the 80 vs. 30% 1RM group at Week 6, and only training at 80% 1RM elicited a significant increase in EMG amplitude during MVIC. The peak twitch torque to MVIC ratio was also significantly reduced in the 80%, but not 30% 1RM group, at Week 3 and 6. Finally, VA and EMG amplitude were reduced during submaximal torque production as a result of training at 80% 1RM, but not 30% 1RM. Despite eliciting similar hypertrophy, 80% 1RM improved muscle strength more than 30% 1RM, and was accompanied by increases in VA and EMG amplitude during maximal force production. Furthermore, training at 80% 1RM resulted in a decreased neural cost to produce the same relative submaximal torques after training, whereas training at 30% 1RM did not. Therefore, our data suggest that high-load training results in greater neural adaptations that may explain the disparate increases in muscle strength despite similar hypertrophy following high- and low-load training programs.

Chronic eccentric arm cycling improves maximum upper-body strength and power

INTRODUCTION

Eccentric leg cycling (cycle ergometry adapted to impose muscle lengthening contractions) offers an effective exercise for restoring lower-body muscular function, maintaining health, and improving performance in clinical and athletic populations.

PURPOSE

We extended this model to the upper body and evaluated the effectiveness of a 7-week eccentric arm cycling (ECC_arm) intervention to improve upper-body muscular function. We also explored whether ECC_arm would alter arterial function.

METHODS

Participants performed ECC_arm (n = 9) or concentric arm cycling (CON_arm; n = 8) 3×/week while training intensity increased (5-20 min, 60-70% upper-body peak heart rate). Maximum elbow extensor strength, upper-body concentric power, and peripheral and central arterial stiffness were assessed before and after training.

RESULTS

During training, heart rates and perceived exertion did not differ between groups (~68% upper-body peak heart rate, ~12 Borg units, both P > 0.05), whereas power during ECC_arm was ~2× that for CON_arm (122 ± 43 vs. 59 ± 20 W, P < 0.01). Muscle soreness for ECC_arm was greater than CON_arm (P = 0.02), however, soreness was minimal for both groups (<0.50 cm). Following training, ECC_arm exhibited greater changes in elbow extensor strength (16 ± 10 vs. 1 ± 9%, P = 0.01) and upper-body power (6 ± 8 vs. -3 ± 7%, P < 0.01) compared to CON_arm. Peripheral and central arterial stiffness did not change for either group (both P > 0.05).

CONCLUSION

Upper-body eccentric exercise improved dynamic muscular function while training at low exertion levels. Results occurred with minimal soreness and without compromising arterial function. ECC_arm findings parallel eccentric leg cycling findings and indicate that eccentric cycle ergometry offers a robust model for enhancing upper-body muscular function. ECC_arm could have applications in rehabilitation and sport training.

Mind-muscle connection training principle: influence of muscle strength and training experience during a pushing movement

PURPOSE

To investigate the effect of different attentional focus conditions on muscle activity during the push-up exercise and to assess the possible influence of muscle strength and training experience.

METHODS

Eighteen resistance-trained men performed 1RM bench press testing and were familiarized with the procedure during the first session. In the second session, three different conditions were randomly performed: regular push-up and push-up focusing on using the pectoralis major and triceps brachii muscles, respectively. Surface electromyography (EMG) was recorded and analyzed (EMG normalized to max; nEMG) for the triceps brachii and pectoralis major muscles.

RESULTS

Participants had on average 8 (SD 6) years of training experience and 1RM of 1.25 (SD 0.28) kg per kg bodyweight. Focusing on using pectoralis major increased activity in this muscle by 9% nEMG (95% CI 5-13; Cohen's d 0.60) compared with the regular condition. Triceps activity was not significantly influenced by triceps focus although borderline significant, with a mean difference of 5% nEMG (95% CI 0-10; Cohen's d 0.30). However, years of training experience was positively associated with the ability to selectively activate the triceps (β = 0.41, P = 0.04), but not the pectoralis. Bench press 1RM was not significantly associated with the ability to selectively activate the muscles.

CONCLUSION

Pectoralis activity can be increased when focusing on using this muscle during push-ups, whereas the ability to do this for the triceps is dependent on years of training experience. Maximal muscle strength does not appear to be a decisive factor for the ability to selectively activate these muscles.

Cross-education after high-frequency versus low-frequency volume-matched handgrip training

INTRODUCTION

Cross-education training programs cause interlimb asymmetry of strength and hypertrophy. We examined the cross-education effects from a high-frequency (HF) versus a low-frequency (LF) volume-matched handgrip training program on interlimb asymmetry.

METHODS

Right-handed participants completed either HF (n = 10; 2 × 6 repetitions 10 times per week) or LF (n = 9; 5 × 8 repetitions 3 times per week) training. Testing occurred twice before and once after 4 weeks of right-handed isometric handgrip training totaling 120 weekly repetitions. Measures were maximal isometric handgrip and wrist flexion torque, muscle thickness, and muscle activation (electromyography; EMG).

RESULTS

Grip strength was greater in both limbs posttraining, pooled across groups (P < 0.001). Trained limb muscle thickness increased in both groups (P < 0.05; untrained, P = 0.897). EMG and wrist flexion torque did not change (all P > 0.103).

DISCUSSION

Both LF and HF induced cross-education of grip strength to the untrained limb, but HF did not reduce asymmetry. These findings have implications for injury rehabilitation. Muscle Nerve 56: 689-695, 2017.

Does short-term gluteal activation enhance muscle performance?

A reduction in gluteus maximus (GM) strength may contribute to the etiology of musculoskeletal impairments and lower-extremity injuries. Currently, there is a paucity of evidence regarding the efficacy of implementing a short-term gluteal activation programme to improving muscle performance. Twenty four semi-professional rugby males were assigned randomly to a gluteal activation group (GLUTE) or a control group (CON). During the 6-week training intervention, the GLUTE and CON groups performed the same training, however that GLUTE group performed seven gluteal activation exercises three times weekly prior to their normal training sessions. Whilst the CON group performed the conventional training with no gluteal activation exercises. Electromyography (EMG) was measured during a maximal isometric unilateral squat (MVIC) and unilateral hip extension force from the left and right vastus lateralis, gluteus maximus, and biceps femoris. After 6 weeks of training there was no significant main or interaction effect (p > 0.05) of EMG and peak force for MVIC and hip extension between GLUTE and CON. The current gluteal activation programme did not enhance EMG activity and hip extension force therefore, the body-weight exercises may not have been sufficient to elicit the appropriate changes.

MORPHOLOGICAL ADJUSTMENTS OF THE RADIAL NERVE ARE INTENSITY-DEPENDENT

ABSTRACT Introduction: Peripheral nerve adaptation is critical for strength gains. However, information about intensity effects on nerve morphology is scarce. Objective: To compare the effects of different intensities of resistance training on radial nerve structures. Methods: Rats were divided into three groups: control (GC), training with 50% (GF1) and training 75% (GF2) of the animal’s body weight. The morphological analysis of the nerve was done by light and transmission electron microscopy. One-way ANOVA and the Tukey’s post hoc test were applied and the significance level was set at p≤0.05. Results: Training groups had an increase of strength compared to GC (p≤0.05). All measured nerve components (mean area and diameter of myelin fibers and axons, mean area and thickness of the myelin sheath, and of neurofilaments and microtubules) were higher in GF2 compared to the other (p≤0.05). Conclusion: Results demonstrated greater morphological changes on radial nerve after heavier loads. This can be important for rehabilitation therapies, training, and progression.

Effectiveness of Cardiac Rehabilitation for Prevention and Treatment of Sarcopenia in Patients with Cardiovascular Disease - A Retrospective Cross-Sectional Analysis

OBJECTIVE

Sarcopenia is a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength, with the risk of frailty and poor quality of life. This study aimed to clarify the clinical characteristics of sarcopenia and to investigate the effects of comprehensive cardiac rehabilitation (CCR), including nutrition, physical exercise and medication, in patients with cardiovascular disease (CVD).

METHODS

We retrospectively studied 322 inpatients with CVD (age 72±12 years). Muscle mass, muscle strength and physical performance were assessed before and after exercise training in patients with and without sarcopenia, which was defined as either a gait speed of <0.8 m/s or reduced handgrip strength (<26 kg in males and <18 kg in females), together with lower skeletal muscle index (SMI) (<7.0 kg/m2 in males and <5.7 kg/m2 in females). The actual daily total calorie and nutrient intake was also calculated.

RESULTS

Sarcopenia was identified in 28% of patients with CVD, these patients having a higher prevalence of symptomatic chronic heart failure and chronic kidney disease. SMI was significantly associated with protein intake and statin treatment. The ratio of peak VO2 and SMI was significantly higher in the statin treatment group. Handgrip strength, gait speed, leg weight bearing index, and nutritional intake improved after exercise training in patients both with and without sarcopenia.

CONCLUSIONS

The present findings suggest that CCR is a promising strategy for prevention and treatment of sarcopenia in patients with CVD.

Squat test performance and execution in children with and without cerebral palsy

BACKGROUND

Knowledge on lower extremity strength is imperative to informed decision making for children with cerebral palsy (CP) with mobility problems. However, a functional and clinically feasible test is not available. We aimed to determine whether the squat test is suitable for this purpose by investigating test performance and execution in children with cerebral palsy and typically developing (TD) peers.

METHODS

Squat test performance, defined by the number of two-legged squats until fatigue (max 20), was assessed in twenty children with bilateral CP (6-19years; gross motor function classification system I-III) and sixteen TD children (7-16years). Muscle fatigue was assessed from changes in electromyography (EMG). Joint range-of-motion and net torque were calculated for each single squat, to investigate differences between groups and between the 2nd and last squat.

FINDINGS

Fifteen children with CP performed <20 squats (median=13, IQR=7-19), while all TD children performed the maximum of 20 squats. Median EMG frequency decreased and amplitude increased in mm. quadriceps of both groups. Ankle and knee range-of-motion were reduced in children with CP during a single squat by 10 to 15°. No differences between 2nd and last squat were observed, except for knee range-of-motion which increased in TD children and decreased in children with CP.

INTERPRETATION

Squat test performance was reduced in children with CP, especially in those with more severe CP. Muscle fatigue was present in both children with CP and TD peers, confirming that endurance of the lower extremity was tested. Minor execution differences between groups suggest that standardized execution is important to avoid compensation strategies. It is concluded that the squat test is feasible to test lower extremity strength in children with CP in a clinically meaningful way. Further clinimetric evaluation is needed before clinical implementation.