The effect of local and general fatigue on knee proprioception

Gender differences in the impact of fatigue on lower limb landing biomechanics and their association with anterior cruciate ligament (ACL) injuries: A systematic review and meta-analysis

BACKGROUND

This meta-analysis examines the impact of neuromuscular fatigue on gender differences in lower limb landing biomechanics and its correlation with ACL injury risk.

METHODS

A comprehensive search was conducted in PubMed, Scopus, Web of Science, Embase, and the Cochrane Library up to March 2024.

RESULTS

Fourteen studies were included, averaging a quality score of 6.79; nine were high quality. Key findings: males showed a significant increase in knee flexion angle at initial contact (effect size -1.23), but females did not (-0.25). Both genders had significant changes in hip external rotation (males: 1.35, females: 1.20). Ankle peak dorsiflexion angle increased (-1.69) with no gender differences. Peak Knee extension moment increased in males (0.76) and females (0.48) with an overall effect size of 0.64, but no change in peak abduction moment. Peak Hip extension moment was significant in males (0.58) and overall (0.51), with no changes in internal rotation or adduction moments. Peak vertical ground reaction force showed no significant changes for either gender.

CONCLUSIONS

Fatigue alters knee biomechanics in males, raising ACL injury risk, and both genders show increased hip and ankle loads post-fatigue. These results suggest the need for gender-specific fatigue management strategies to mitigate ACL injury risk and call for further research into prevention mechanisms.

Neck muscle fatigue disrupts self-motion perception

The effect of neck muscle fatigue induced by prolonged isometric contraction of the neck extensor muscles on self-motion perception was studied. The magnitude of self-motion perception was assessed by evaluating the tracking of a remembered earth-fixed visual target during passive symmetric and asymmetric sinusoidal horizontal body rotation. The trunk was rotated on a stationary head for examining the role of neck proprioception and the whole-body for that of the vestibular system. To induce neck extensor muscle fatigue, participants held their head extended against a load for several minutes. Perceptual responses were examined before and during neck muscle fatigue. It was found that the perception of the movement was diminished by neck muscle fatigue as shown by a reduction of the amplitude of the tracking during trunk rotation. This suggests that fatigue affects the motion perception when the neck proprioceptive system was activated by the rotation. This effect has been observed only during slow rotation, while the responses remained unmodified during fast rotation. In contrast, neck muscle fatigue did not affect the tracking when rotation activated only the vestibular system. Furthermore, neck muscle fatigue abolished the effect of tonic head deviation on perceptual responses to whole-body rotation. Therefore, neck muscle fatigue alters the self-motion perception reducing the ability of the proprioceptive system to signal slow trunk rotations and the position of the head relative to the trunk during body movements.

Control Mechanisms of Sensorimotor System on Manipulation of Proprioceptive Inputs During Balance Maintenance

Proprioceptive inputs have crucial roles in control of the posture. The aim of the present study was to assess the effect of interfering with these signals on postural stability by ice-induced anaesthesia and local calf muscle fatigue. Seventeen healthy young individuals participated in this study to stand quietly and on an unstable platform under normal, anaesthesia, and fatigue conditions. A force platform calculated excursions of centre of pressure. Stabilogram-diffusion analysis was utilised to evaluate how body controls the posture with and without proprioceptive inputs. Time intervals of using the sensory feedback is significantly increased by anaesthesia in quiet standing (430 ms, p = 0.034) to note more delayed use of sensory information in a closed-loop. Additionally, fatigue significantly increased the time intervals of using sensory feedback during standing on the unstable platform (290 ms, p = 0.016). Interestingly, sensory interventions had no effect on the stability of the open-loop control of posture (short-term control), but they significantly influenced the closed-loop control (long-term control) (p < 0.004). Specifically, fatigue led to increased instabilities when the body used sensory inputs during both quiet standing (p = 0.021) and standing on the unstable platform (p = 0.041). These findings highlight the importance of proprioception in balance control for healthy individuals. Interfering with proprioceptive inputs, either through anaesthesia or fatigue, resulted in instabilities during balance maintenance. Our study provides new insights into the mechanisms underlying postural control, emphasising the significance of proprioceptive inputs. Understanding how proprioception affects balance maintenance may have implications for rehabilitation strategies, injury prevention, and the development of interventions to improve postural stability.

Successful ACL repair by dynamic intraligamentary stabilisation is non-inferior in functional performance and worse in proprioception compared to healthy controls in a case-matched study

Purpose

The primary aim of this study was to assess non-inferiority in functional performance of the knee after dynamic intraligamentary stabilisation (DIS) surgery at a minimal follow-up of 1 year compared to healthy controls, based on limb symmetry index (LSI) of the single leg hop test (SLH). Additionally, functional performance based on the single leg triple hop test (SLTH) and side hop test (SH), proprioception and subjective outcome were evaluated.

Methods

A total of 45 DIS patients were 1-to-1 matched to a healthy control. Functional performance was evaluated by LSI and absolute values on the SLH, SLTH and SH. Proprioception was assessed by joint position sense (JPS) test and International Knee Documentation Committee (IKDC) scores were obtained.

Results

Non-inferiority in functional performance after DIS compared to healthy controls was confirmed based on the mean LSI of the SLH and SLTH (97.6% vs. 99.6% and 97.5% vs. 100.6%, respectively) and non-confirmed on the SH (98.8% vs. 100.0%, respectively). No significant differences were found in absolute value of the SLH and SLTH and a significantly higher absolute value of the SH was found in the DIS group (p = 0.01). JPS absolute angular error was significantly higher in the DIS group compared to the control group (p = 0.01). The median IKDC score of the DIS group was significantly lower (92, IQR 85-95) than the control group (100, IQR 99-100), p < 0.001.

Conclusions

In conclusion, functional performance after DIS was confirmed non-inferior compared to healthy controls based on the SLH and SLTH, although non-confirmed on the SH.

Level of evidence

Level III.

Effects of slow dynamic, fast dynamic, and static stretching on recovery of performance, range of motion, balance, and joint position sense in healthy adults

INTRODUCTION

Considering the effects of fatigue on athletic performance and the subsequent increase in the probability of injury, the purpose of this study was to compare the effects of slow dynamic, fast dynamic, and static stretching on the recovery of performance, range of motion (ROM), balance, and joint position sense.

METHODS

Fifteen collegiate healthy females were involved in four separate sessions of slow dynamic stretching (SDS), fast dynamic stretching (FDS), static stretching (SS), and control condition (CC; without stretching), in a random order with at least 48 h of rest between sessions. After warming up, the individuals performed ROM, balance, joint position sense (JPS) maximum voluntary isometric contraction (MVIC) force as well as countermovement (CMJ) and squat jump (SJ) as pre-tests. After performing the knee fatigue protocol of 4 sets of knee extension and flexion at 60% of 1 repetition maximum (RM) to exhaustion (CC; without stretching) or stretching programs (SDS or FDS or SS), the subjects repeated all the tests at post-test 1 (after 5 min) and post-test 2 (after 60 min).

RESULTS

A significantly lower JPS error was detected with SDS while JPS error increased in the SS and control conditions (p < 0.0001). MVIC force significantly increased with SDS and FDS but decreased in control and SS conditions (p < 0.0001). Moreover, a significant decrease in CMJ and SJ height in SS and control conditions was revealed (p < 0.0001). Also, a significant decrease in balance with the control condition was revealed. But only SDS minimized fatigue-induced balance decrements (p < 0.0001). Additionally, the control condition experienced a significant decrease in knee extensor ROM, which contrasted with the significant increase in the quadriceps flexibility with the stretching conditions.

CONCLUSIONS

The present results support the idea that SDS may increase quadriceps MVIC force, knee extensor ROM and knee JPS. So according to the present results, it is suggested that the SDS could be implemented and incorporated into a regular recovery program.

Factors that influence the angular error in active knee angle reproduction tests: A systematic review and meta-analysis

Purpose

The systematic review and meta-analysis investigated subject-independent test factors that influence the absolute angle error in active knee angle reproduction tests.

Methods

Five electronic databases were searched to identify relevant studies published before 20 December 2023. Studies were included that were published in either English or German and that investigated joint proprioception in the healthy knee. Included studies were also required to have participants 18-60 years old and free of lower-limb injury, neurological disorders and diseases affecting joint position sense. Risk of bias was assessed using a Cochrane risk-of-bias tool.

Results

Of the 2023 articles identified, 26 studies (1082 participants) were included in the meta-analysis. The meta-analysis showed a significant pooled standard mean difference in the absolute angular error for body orientation, direction of movement and fatigue. Active knee angle reproduction tests were found to have a lower absolute angular error when performed in the sitting position compared to the prone position (SMD = -0.56; 95% CI = -1.00 to -0.12). The absolute angular error was found to be greater in cases of knee flexion compared to knee extension (SMD = 0.71; 95% CI = 0.18-1.24). General and local muscle fatigue were found to result in a higher absolute angular error (SMD = 1.39; 95% CI = 1.04-1.75).

Conclusion

Hence, fatigue, body orientation and direction of movement influence the extent of the absolute angular error in active knee angle reproduction tests. Practitioners should be aware that the test conditions and the patient's level of fatigue can affect the results of such tests and that directly comparing results obtained using different test protocols may not be appropriate. The test protocol should be well documented and applied consistently in the clinical setting.

Level of Evidence

Level III, systematic review with meta-analysis.

Effects of Muscular Fatigue on Position Sense in Two Phases of the Menstrual Cycle

It is generally accepted that local muscular fatigue can negatively affect position sense. Interestingly, it has been proposed that in women, position sense and neuromuscular coordination may be affected by fluctuations of estrogen and progesterone levels. The aim of this study was to examine the possible effect of localized muscle fatigue on knee joint position sense at two phases of the menses: follicular and luteal. Twenty physically active females aged 19-30 years, with normal menses, volunteered for this study. An isokinetic dynamometer was used to evaluate proprioception and perform the fatigue protocol of the knee extensors and flexors. Knee proprioception at rest and after fatigue at three knee target angles (30°, 45°, 60°) was measured. A three-way ANOVA analysis with repeated measures was performed. The results showed that the main effect of fatigue was significant, but no main effect of the menstrual cycle phase was found. Additionally, a main effect was found for the target angle (more flexed target knee joint angles were associated with larger angular error deviations). In conclusion, localized muscle fatigue can significantly reduce the accuracy of active knee joint repositioning in both the luteal and the follicular menstrual phases in young, physically active healthy women.

Influence of taping on joint proprioception: a systematic review with between and within group meta-analysis

Taping is increasingly used to manage proprioceptive deficits, but existing reviews on its impact have shortcomings. To accurately assess the effects of taping, a separate meta-analyses for different population groups and tape types is needed. Therefore, both between- and within-group meta-analyses are needed to evaluate the influence of taping on proprioception. According to PRISMA guidelines, a literature search was conducted across seven databases (Web of Science, PEDro, Pubmed, EBSCO, Scopus, ERIC, SportDiscus, Psychinfo) and one register (CENTRAL) using the keywords "tape" and "proprioception". Out of 1372 records, 91 studies, involving 2718 individuals, met the inclusion criteria outlined in the systematic review. The meta-analyses revealed a significant between and within-group reduction in repositioning errors with taping compared to no tape (Hedge's g: -0.39, p < 0.001) and placebo taping (Hedge's g: -1.20, p < 0.001). Subgroup and sensitivity analyses further confirmed the reliability of the overall between and within-group analyses. The between-group results further demonstrated that both elastic tape and rigid tape had similar efficacy to improve repositioning errors in both healthy and fatigued populations. Additional analyses on the threshold to detection of passive motion and active movement extent discrimination apparatus revealed no significant influence of taping. In conclusion, the findings highlight the potential of taping to enhance joint repositioning accuracy compared to no tape or placebo taping. Further research needs to uncover underlying mechanisms and refine the application of taping for diverse populations with proprioceptive deficits.

Lateral Shuffle-Induced Fatigue Effects on Ankle Proprioception and Countermovement Jump Performance

To determine how lateral shuffling/lateral shuffle (LS) -induced fatigue affects ankle proprioception and countermovement jump (CMJ) performance. Eighteen male college athletes performed 6 modes of a repeated LS protocol with 2 distances (2.5 and 5 m) and 3 speeds (1.6, 1.8, and 2.0 m/s). After LS, ankle inversion proprioception (AIP) was measured using the active movement extent discrimination apparatus (AMEDA). CMJ, blood lactate (BLa), heart rate (HR) and rating of perceived exertion (RPE) were measured before and after LS. The number of changes of direction (CODs) in each protocol was recorded. LS-induced fatigue was evident in BLa, HR and RPE (all p < 0.05), increasing with shorter shuffle distance and faster speed. RM-ANOVA showed a significant distance main effect on both AIP (p < 0.01) and CMJ (p < 0.05), but the speed main effect was only significant for CMJ (p ≤ 0.001), not AIP (p = 0.87). CMJ performance was correlated with BLa, HR and RPE (r values range from -0.62 to -0.32, all p ≤ 0.001). AIP was only correlated with CODs (r = -0.251, p < 0.01). These results suggested that in LS, shorter distance, regardless of speed, was associated with worse AIP, whereas subsequent CMJ performance was affected by both LS distance and speed. Hence, AIP performance was not related to physiological fatigue, but CMJ performance was. Results imply that LS affects processing proprioceptive input and producing muscular output differently, and that these two aspects of neuromuscular control are affected by physiological fatigue to varying degrees. These findings have implications for injury prevention and performance enhancement.

The Effect of Muscle Fatigue on the Knee Proprioception: A Systematic Review

This study aimed to systematically review and summarise the evidence about the effect of muscle fatigue on the knee proprioception of trained and non-trained individuals. A search in PubMed, Scopus, Web of Science and EBSCO databases and Google Scholar was conducted using the expression: "fatigue" AND ("proprioception" OR "position sense" OR "repositioning" OR "kinesthesia" OR "detection of passive motion" OR "force sense" OR "sense of resistance") AND "knee". Forty-two studies were included. Regarding joint-position sense, higher repositioning errors were reported after local and general protocols. Kinesthesia seems to be more affected when fatigue is induced locally, and force sense when assessed at higher target forces and after eccentric protocols. Muscle fatigue, both induced locally or generally, has a negative impact on the knee proprioception.

The effectiveness of fatigue on repositioning sense of lower extremities: systematic review and meta-analysis

INTRODUCTION

An injury can significantly harm both individual and team performance. One of the most important risk factors for sports-related injuries, especially non-collision injuries, is fatigue. It seems that poor proprioception may play an essential role to impose athletes to further injuries. This systematic review and meta-analysis aimed to examine the effectiveness of fatigue on the repositioning sense of the lower extremity joints.

METHOD

The electronic databases, including PubMed, Web of Science, Scopus, and Google Scholar were systematically searched from inception to 11January 2024. The obtained records were exported to the EndNote Software version 8. Then, two investigators examined the records independently to find eligible studies based on the inclusion/exclusion criteria. In the case of disagreements, a consequence method was utilized. The quality of the eligible studies was evaluated using the Downs and Black checklist. Comprehensive Meta-Analysis (CMA) software ver. 3 software was used for statistical analysis. Q-test and I2 were employed to examine the data homogeneity. In addition, considering the risk of bias, the Funnel Plot and trim-and-fill method were used.

RESULTS

After reviewing the titles and abstracts of 3883 studies found in the selected databases, 43 articles were found to be eligible to include in meta-analyses. The results showed that fatigue led to a significant increase in the active absolute error of the knee (SDM = 0.524, 95% CI = 0.406-0.841), ankle in the horizontal plane (SDM = 0.541, 95% CI = 0.367-0.715), ankle in the sagittal plane (SDM = 0.443, 95% CI = 0.088-0.798), and hip (SDM = 0.988, 95% CI = 0.135-1.841). However, fatigue had no significant effects on the passive absolute error of the knee and ankle in horizontal plane and relative angular error of the knee.

CONCLUSION

Fatigue can diminish the active joint position sense of the lower extremities and thus may increase the risk of injury by reducing proprioception. Therefore, future research could be conducted to investigate the potential impact of integrated fatigue-mitigating exercises into athletes' training programs, with the aim of reducing the incidence of sports-related injuries.

Fatigue as a key factor for testing knee stability with single leg drop landing for injury prevention and return to play tests

Objectives

Fatigue can decrease knee stability and increase the injury risk. However, fatigue is rarely being applied throughout movement analysis. The aim of this study was to investigate if the knee stability throughout SLDLs differ between cyclic and acyclic sports, before and after fatigue in general, and between the dominant and non-dominant leg of soccer players.

Methods

A total of 43 active male (n = 34) and female (n = 9) athletes (age: 26.5 ± 7.2) participated in this study with a pre-post-design. Subjects performed a single leg drop landing (SLDL) from a plyobox. For each leg, the two-dimensional frontal plane projection angle (FPPA) was analyzed. After pretesting the shuttle run test was performed until exhaustion, before repeating the measurements.

Results

ANOVA with repeated measures was applied and identified no significance difference for the FPPA between cyclic and acyclic sports (F = 0.98, p = 0.33), a significant difference before and after fatigue (F = 12.49, p = 0.002) and no significant difference between the dominant and non dominant leg of soccer players (F = 4.35, p = 0.26).

Discussion

Fatigue seems to be able to have a significant influence on knee stability in the frontal axis. Therefore, fatigue should be included in motion analysis for injury prevention and return to play tests because during this physical state most injuries happen.

Recovery of pinch force sense after short-term fatigue

The aim of this study was to identify the exact origin of force sense and identify whether it arises centrally or peripherally. The present study was designed to analyze the effects of short-term fatigue on pinch force sense and the duration of these effects. During the fatigue protocol, twenty (10 men and 10 women; Mage = 22.0 years old) young Chinese participants were asked to squeeze maximally until the pinch grip force decreased to 50% of its maximal due to fatigue. Participants were instructed to produce the target force (10% of maximal voluntary isometric contraction) using the same hand before and after fatigue (immediately, 10, 30, 60, 180, 300 s). The results showed significantly higher absolute error immediately after fatigue (1.22 ± 1.06 N) than before fatigue (0.68 ± 0.34 N), and 60 s (0.76 ± 0.69 N), 180 s (0.67 ± 0.42 N), and 300 s (0.75 ± 0.37 N) after fatigue (all P < 0.05) but with no effect on the variable error (P > 0.05). It was also revealed that there was a significant overestimate of the constant error values before (0.32 ± 0.61 N) and immediately after fatigue (0.80 ± 1.38 N, all P < 0.05), while no significant overestimation or underestimation exceeded 300 s after fatigue (P > 0.05). Our study results revealed that short-term fatigue resulted in a significant decrease in force sense accuracy, but it did not affect force sense consistently; however, force sense accuracy recovered to a certain extent within 10 s and 30 s, whereas it recovered fully within 60 s, and force sense directivity improvement exceeded 300 s after fatigue. The present study shows that the sense of tension (peripherally) is also an important factor affecting force sense. Our study supports the view that the periphery is part of the origin of force sense.

Effects of fatigue on balance and ankle proprioception during drop landing among individuals with and without chronic ankle instability

This study aimed to explore the effects of fatigue on the balance and ankle proprioception during drop landing of individuals with chronic ankle instability (CAI). A total of 35 participants with unilateral CAI and 35 healthy participants participated in this study. A static balance test, dynamic balance test, and ankle proprioception test were conducted before and after fatigue. Fatigue was induced with turn back runs and vertical jumps protocol. Sway distance of the center of pressure (COP), root mean square of the COP (RMS), total excursions (TOTEX), mean velocity (MVELO), 95% confidence ellipse area of the COP movements (95% AREA), Normalise Reach Distance in the anterior (ANT), posteromedial (PM), and posterolateral (PL) directions, and the area under the curve (AUC) were calculated and analyzed. There were significant group by fatigue interactions for static balance variables, normalise reach distance in the PM and PL directions, and AUC. Fatigue reduced balance and ankle proprioception in individuals with CAI. After fatigue, static and dynamic balance and ankle proprioception during drop landing were significantly worse in the CAI group than in the control group. Fatigue had a significant negative effect on balance and ankle proprioception in CAI patients. Therefore, fatigue may be an important factor causing repeated ankle sprain in CAI patients.

Wrist Proprioception in Adults with and without Subacute Stroke

Proprioception is critical to motor control and functional status but has received limited study early after stroke. Patients admitted to an inpatient rehabilitation facility for stroke (n = 18, mean(±SD) 12.5 ± 6.6 days from stroke) and older healthy controls (n = 19) completed the Wrist Position Sense Test (WPST), a validated, quantitative measure of wrist proprioception, as well as motor and cognitive testing. Patients were serially tested when available (n = 12, mean 11 days between assessments). In controls, mean(±SD) WPST error was 9.7 ± 3.5° in the dominant wrist and 8.8 ± 3.8° in the nondominant wrist (p = 0.31). In patients with stroke, WPST error was 18.6 ± 9° in the more-affected wrist, with abnormal values present in 88.2%; and 11.5 ± 5.6° in the less-affected wrist, with abnormal values present in 72.2%. Error in the more-affected wrist was higher than in the less-affected wrist (p = 0.003) or in the dominant (p = 0.001) and nondominant (p < 0.001) wrist of controls. Age and BBT performance correlated with dominant hand WPST error in controls. WPST error in either wrist after stroke was not related to age, BBT, MoCA, or Fugl-Meyer scores. WPST error did not significantly change in retested patients. Wrist proprioception deficits are common, bilateral, and persistent in subacute stroke and not explained by cognitive or motor deficits.

Effects of compression running pants and treadmill running stages on knee proprioception and fatigue-related physiological responses in half-marathon runners

Background: Knee injury is common in half-marathon runners, however, the effect of compression running pants on fatigue and knee proprioception remains unclear. Objectives: The study aims to investigate whether wearing compression running pants (CRP) and treadmill running stages affect knee proprioception and fatigue-related physiological responses during half-marathon running. Methods: Eighteen half-marathon runners completed two self-paced 21 km treadmill running trials, once wearing CRP and once wearing loose running shorts (LRS). For each 21 km run, RPE, heart rate, blood lactic acid, and knee flexion proprioception were assessed before starting, and after each 7 km stage. Results: Data analysis revealed no difference between CRP and LRS conditions in heart rate, RPE, or blood lactic acid. Repeated measures ANOVA showed a significant garment condition main effect whereby wearing CRP was associated with higher knee proprioceptive acuity (p = 0.006). Polynomial trend analysis showed a significant linear downwards trend in proprioceptive acuity across the four measurement occasions (p = 0.048). Stage analysis showed that wearing CRP was associated with better knee proprioception at running distances of 14 km (p = 0.007, 95%CI = -0.054, -0.010) and 21 km (p = 0.016, 95%CI = -0.051, -0.006). Conclusion: Compression running pants provide an overall positive effect on knee proprioception, particularly after 14 km and 21km, which may reduce the probability of knee injury. CRP had no significant effect on physiological measures in half-marathon running.

The effect of fatigue on electromechanical response times in basketball players with and without persistent low back pain

Typically, athletes alter movement mechanics in the presence of back pain, but the effect of these changes on lower extremity injury risk is not well understood. This study aimed to compare the effect of fatigue on electromechanical response times during a choice reaction task in basketball players with and without persistent low back pain. Twenty-four male basketball players participated. Total reaction time (TRT), premotor time (PMT), and electromechanical delay (EMD data were recorded before and after fatigue. The chronic low back pain (CLBP) group had significantly longer EMD in Med gastrocnemius (p = 0.001) and Tibialis anterior (p = 0.001), and shorter EMD in Vastus Lateralis (p = 0.001), Vastus Medialis Oblique (p = 0.003), and Semitendinosus (p = 0.025) muscles after fatigue. PMT in the CLBP group had longer than the Non-CLBP in Vastus Lateralis (p = 0.010), Vastus Medialis Oblique (p = 0.017), Semitendinosus (p = 0.002). Also, TRT was longer in knee flexion (p = 0.001) and ankle plantarflexion (p = 0.001) muscle groups. The different effects of fatigue on electromechanical response times of the knee and ankle in people with CLBP may represent the effect of an axial injury on lower extremity injury risk factors in situations of higher cognitive load, similar to competitive play.

The effects of experimentally-induced fatigue on gait parameters during obstacle crossing: A systematic review

Striking an obstacle while walking can be dangerous, reflecting the higher risks of losing one's balance, tripping and falling. Particular situations during which internal resources are limited, such as in a fatigued state, may impair performance when crossing obstacles, enhancing the risks of falls or accidents. Our goal was thus to review the effects of experimentally-induced fatigue (EIF) on gait parameters during obstacle crossing by healthy individuals. We systematically searched PubMed and Web of Science databases using 'fatigue', 'obstacle crossing' and their equivalent terms to extract data from studies investigating this domain. Nine studies were found. First, EIF-related effects on kinetics, EMG and obstacle contacts have been poorly studied. Second, consistent and inconsistent results were found in the kinematic outcomes after EIF. Consistent results included reductions in stride duration and increased step width. Inconsistent results included gait velocity (no-effect vs increased), leading and trailing-foot vertical clearance (reduced vs increased) and horizontal distance from foot to the obstacle before obstacle avoidance (no-effect vs increased). These findings should be interpreted cautiously, however, due to the heterogeneity of the obstacle crossing and EIF protocols.

Correlation and comparison of quadriceps endurance and knee joint position sense in individuals with and without unilateral knee osteoarthritis

Background

Knee osteoarthritis (KOA) is a painful degenerative joint disease that may limit activities of daily living. This study aimed to determine the relationship between quadriceps endurance and knee joint position sense (JPS) in KOA individuals and compare the quadriceps endurance and knee JPS with and without KOA.

Methods

This comparative cross-sectional study was conducted in medical rehabilitation clinics, King Khalid University, Saudi Arabia. This study recruited 50 individuals diagnosed with unilateral KOA (mean age = 67.10 ± 4.36 years) and 50 asymptomatic individuals (mean age = 66.50 ± 3.63 years). Quadriceps isometric endurance capacity (sec) was measured using a fatigue resistance test, and knee JPS (degrees) were assessed using a digital inclinometer and evaluated in sitting and standing positions.

Results

Quadriceps isometric endurance showed a significant moderate negative correlation with knee JPS in 20° of flexion (r = -0.48, p < 0.001); 40° of flexion: r = -0.62, p < 0.001; 60° of flexion: r = -0.58, p < 0.001) in sitting and 20° of flexion (r = -0.25, p = 0.084) in standing position in KOA individuals. When compared to the asymptomatic, the quadriceps endurance was lower (p < 0.001), and knee joint position errors were larger (p < 0.001) in KOA individuals.

Conclusion

Results of this study showed that quadriceps endurance capacity is negatively associated with knee JPS. KOA individuals demonstrated lower quadriceps endurance and larger JPS compared to asymptomatic.

The demands of the extra-time period of soccer: A systematic review

OBJECTIVE

Soccer match-play is typically contested over 90 min; however, in some cup and tournament scenarios, when matches are tied, they proceed to an additional 30 min, which is termed "extra-time" (ET). This systematic review sought to appraise the literature available on 120-min of soccer-specific exercise, with a view to identifying practical recommendations and future research opportunities.

METHODS

The review was conducted according to the PRISMA guidelines. Independent researchers performed a systematic search of PubMed, CINAHL, and PsycINFO in May 2019, with the following keywords entered in various combinations: "soccer", "football", "extra-time", "extra time", "extratime", "120 minutes", "120 min", "additional 30 minutes", and "additional 30 min".

RESULTS

The search yielded an initial 73 articles. Following the screening process, 11 articles were accepted for analyses. Articles were subsequently organized into the following 5 categories: movement demands of ET, performance responses to ET, physiological and neuromuscular response during ET, nutritional interventions, and recovery and ET. The results highlighted that during competitive match-play, players cover 5%-12% less distance relative to match duration (i.e., meters per minute) during ET compared to the preceding 90 min. Reductions in technical performance (i.e., shot speed, number of passes and dribbles) were also observed during ET. Additionally, carbohydrate provision may attenuate and improve dribbling performance during ET. Moreover, objective and subjective measures of recovery may be further compromised following ET when compared to 90 min.

CONCLUSION

Additional investigations are warranted to further substantiate these findings and identify interventions to improve performance during ET.

Heavy-intensity cycling and running work-rate associated to VO2max affects isokinetic strength, the dynamic control ratio but not the conventional H:Q ratio

BACKGROUND: Bilateral strength asymmetry and fatigue predispose athletes to various injuries and conventional methods appear to be poor predictors of lower extremity muscular performance under NF conditions. OBJECTIVE: The purpose of the study was to compare the conventional Hcon/Qcon (HQR) ratio and the dynamic control ratio (DCR: Hecc/Qcon) under non-fatiguing (NF) and fatiguing (F) conditions and verify the effects of heavy-intensity constant running and cycling exercise on the isokinetic performance. METHODS: Twenty healthy male participants performed running and cycling VO2max at work-rate associated with the achievement of VO2max (TTE). Isokinetic muscle strength performance was tested at 60 and 180∘/s before and after these sessions with 48-hour intervals. Quadriceps (QFR) and hamstring (HFR) muscle fatigue rates were also calculated during these sessions. Blood lactate concentration was measured before and two-minutes after running and cycling TTE. RESULTS: No between-condition differences were found for the HQR while the DCR decreased significantly at 180∘/s following cycling and running sessions (p< 0.05). Cycling TTE was positively correlated with in dominant (r= 0.535, p= 0.015) and non-dominant (r= 0.446, p= 0.048) QFR. Positive correlations were also found between running TTE and dominant (r= 0.500, p= 0.25) and non-dominant (r= 0.465, p= 0.039) HFR. CONCLUSIONS: The DCR obtained at fast angular velocities following a strenuous exercise seems to be the best indicator of muscle performance while its assessment under F conditions reveals higher ratios compared to NF conditions and conventional methods.

Correlation of eccentric strength of the knee extensors and knee proprioception with dynamic postural control

BACKGROUND

It is important for clinicians and researchers to perform dynamic postural control evaluation for predicting musculoskeletal conditions, injury prevention, and rehabilitation.

OBJECTIVE

The purpose of this study was to investigate the relationship (1) between the eccentric strength of the knee extensors and star excursion balance test (SEBT), and (2) between the knee proprioception and SEBT.

METHODS

Forty healthy young adults participated in this study. The eccentric peak torque (EPT) of the knee extensors, joint position sense, and force sense were measured. The participants also performed SEBT. Pearson's product-moment correlation and multiple linear regression analysis were used to determine the relationship between the variables and SEBT.

RESULTS

The posteromedial direction of the SEBT was positively and strongly correlated with EPT (r= 0.74, P< 0.01). The anterior and posterolateral directions were positively and moderately correlated with EPT (r= 0.46, P< 0.01, and r= 0.69, P< 0.01, respectively.). However, knee proprioception was not correlated with all the directions of SEBT (P> 0.05). According to the results of multiple linear regression analysis, EPT of the knee extensors significantly predicted SEBT reach distances.

CONCLUSION

The eccentric strength of the knee extensors seems to be an essential factor in dynamic postural control. However, the knee proprioception did not show a significant correlation with SEBT.

Effects of compression garment on muscular efficacy, proprioception, and recovery after exercise-induced muscle fatigue onset for people who exercise regularly

Fatigue is a major cause of exercise-induced muscle damage (EIMD). Compression garments (CGs) can aid post-exercise recovery, therefore, this study explored the effects of CGs on muscular efficacy, proprioception, and recovery after exercise-induced muscle fatigue in people who exercise regularly. Twelve healthy participants who exercised regularly were enrolled in this study. Each participant completed an exercise-induced muscle fatigue test while wearing a randomly assigned lower-body CG or sports pants (SP); after at least 7 days, the participant repeated the test while wearing the other garment. The dependent variables were muscle efficacy, proprioception (displacements of center of pressure/COP, and absolute error), and fatigue recovery (muscle oxygen saturation/SmO2, deoxygenation and reoxygenation rate, and subjective muscle soreness). A two-way repeated measure analysis of variance was conducted to determine the effect of garment type. The results indicated that relative to SP use, CG use can promote muscle efficacy, proprioception in ML displacement of COP, and fatigue recovery. Higher deoxygenation and reoxygenation rates were observed with CG use than with SP use. For CG use, SmO2 quickly returned to baseline value after 10 min of rest and was maintained at a high level until after 1 h of rest, whereas for SP use, SmO2 increased with time after fatigue onset. ML displacement of COP quickly returned to baseline value after 10 min of rest and subsequently decreased until after 1 hour of rest. Relative to SP use, CG use was associated with a significantly lower ML displacement after 20 min of rest. In conclusion, proprioception and SmO2 recovery was achieved after 10 min of rest; however, at least 24 h may be required for recovery pertaining to muscle efficacy and soreness regardless of CG or SP use.

Effects of unilateral and bilateral lower extremity fatiguing exercises on postural control during quiet stance and self-initiated perturbation

Postural control can be more difficult during muscle fatigue. Anticipatory postural adjustments (APAs) and compensatory postural adjustments (CPAs) are the two main postural strategies controlled by the central nervous system. Unchanged or early anticipatory onset together with altered activation magnitude during the APAs phase is observed in the trunk and thigh muscles following unilateral and bilateral fatiguing exercises. Thus far, no studies have compared the effect of such exercises on APAs and CPAs. This study compared the effects of these exercises performed at the same relative workload on center of pressure (COP)-based postural stability measures during quiet stance and electromyography (EMG)-based APAs and CPAs during self-initiated perturbation. Fifteen young male subjects completed the two separated fatiguing sessions; 50% of maximal voluntary contraction force obtained from the unilateral (dominant) and bilateral legs with five sets of 20 times lower limb exercise was respectively applied as unilateral and bilateral fatiguing protocols. Spatio-temporal COP parameters (sway velocity, total displacement, and envelope area) were used to evaluate postural stability, and spectral analysis was performed to estimate the distributions in COP power spectrum. EMG activities of transversus abdominis/internal oblique (TrA/IO) and lumbar multifidus (LMF) were recorded and analyzed during the APAs and CPAs phases. Increased sway velocity and total displacements occurred following both unilateral and bilateral fatiguing exercises; however, the envelope area was not affected. Further, early anticipatory onset of TrA/IO was found after bilateral than after unilateral fatiguing exercise. Co-activation index of the TrA/IO-LMF muscle pair during the CPAs phase increased following both fatiguing sessions. The results partly confirmed previously reported fatigue effects induced by unilateral and bilateral exercises on postural stability. It was observed that APAs onsets were altered differently following a unilateral or bilateral fatiguing exercise, whereas the alterations of CPAs were independent of fatigue conditions. Repetitive unilateral or bilateral fatiguing exercises in patients or athletes may differently alter the anticipatory component of postural control.

Jump performance and mechanics after a regular training bout in elite volleyball players

BACKGROUND

Volleyball is a complex intermittent sport characterized by short explosive technical movements, many of which involve vertical jumping. The assessment of mechanical jumping variables in relation to both injury prevention and performance enhancement through the use of wearable technologies is becoming a new training tool among professional volleyball players.

METHODS

The present study aimed to assess the vertical jumping mechanics before and after a controlled load (volume and intensity) of a routine volleyball training session among male professional players. Twelve male elite professional volleyball players (23.7 ± 4.9 years, 198.1 ± 6.2 cm, 92.2 ± 10.3 kg) of national and international level belonging to the same Brazilian first league team were recruited. Biomechanical analysis of vertical unilateral countermovement jump (CMJ) and bilateral CMJ tests were performed before and after a routine training session of these players at their usual training court. An inertial orientation sensor placed at the third lumbar vertebra was employed for biomechanical data collection.

RESULTS

In relation to the unilateral CMJ, a 10% decrease (p = 0.02) in the vertical ground reaction force after training compared to pre-training values was observed. However, no significant differences were observed in the remaining outcomes. Regarding the bilateral CMJ, no significant differences were observed in all assessed outcomes.

CONCLUSIONS

Our findings showed no evidence of fatigue after a controlled regular in season volleyball training session in professional players. In addition, this volleyball training session induced a significant reduction in the vertical ground reaction force during unilateral CMJ in volleyball players.

Effect of local and general fatiguing exercises on disturbed and static postural control

This study compared the effect of local and general fatiguing exercise on disturbed and static postural control performances. Surface electromyography and center of pressure signals were respectively recorded during self-initiated perturbation test and static postural stability test from 7 young male subjects. Local fatiguing exercise was performed using intermittent isometric knee extensions at the level of 40% of maximal voluntary torques. General fatiguing exercise was implemented with rowing ergometer at a speed of 200 ± 5 m/min. Results of disturbed postural tests showed no significant change of anticipatory postural adjustment (APAs) organizations in individual muscles following both fatiguing exercises, but observed larger APAs coactivations in trunk and dorsal muscle pairs following local than general fatiguing exercise, and larger compensatory postural adjustments (CPAs) coactivation in dorsal muscle pair after both fatiguing exercises. In addition, the results of static postural tests indicated efficient static postural stability accompanying the down-weighting of visual input and the up-weighting of vestibular/somatosensory component following both fatiguing exercises. These findings evidenced a general compensation in the central nervous system in response to the neuromuscular deficiencies induced by local fatiguing exercise and put forward the function of sensory recalibration in maintaining postural stability under fatigue conditions.

Effects of Lower-Body Muscular Fatigue on Vertical Jump and Balance Performance

Cooper, CN, Dabbs, NC, Davis, J, and Sauls, NM. Effects of lower-body muscular fatigue on vertical jump and balance performance. J Strength Cond Res 34(10): 2903-2910, 2020-Lower-body fatigue can lead to a decline in vertical jump (VJ) and balance performance due to decreased motor control and coordination. The purpose is to determine the effects of lower-body fatigue on VJ and balance performance. Twenty-four recreationally trained individuals participated in a single 1-hour familiarization and testing session. Participants were familiarized with balance, countermovement vertical jump (CMVJ), and static vertical jump (SVJ) using the Vertec. Three trials of static and dynamic balance tests were completed. Three trials of a SVJ and CMVJ were completed in a randomized order pre/post fatigue protocol. Three trials of double-leg and single-leg tests were performed. Dependent t tests analyzed differences between pre/post fatigue protocol for jumping and balance measures. There was a significant (p < 0.001) difference between pre/post measures for SVJ-H (height), CMVJ-H, and CMVJ peak power (PP). Results showed an interaction (p < 0.05) for group by time for CMVJ-H, CMVJ-peak force (PF), SVJ-PF, and SVJ-PP. There were no main effects (p > 0.05) for time or group for SVJ-rate of velocity development and SVJ-impact force (IF). There were no interactions, time effects, and group effects for balance variables (p > 0.05). Bosco protocol decreased VJ height and PF in SVJ, and VJ height and PF, IF, peak velocity, and PP for CMVJ potentially due to decreased muscle control, coordination, and force-generating capacity after fatigue. Practitioners should consider fatiguing effects on individuals performing jumping motions but it seems that fatigue has no effect on balance.

Injury prevention of hamstring injuries through exercise interventions

INTRODUCTION

Hamstring injuries are the most prevalent time-loss injuries in sport, mainly in those modalities characterized by high-intensity and short-term actions, especially accelerations and decelerations during high-speed running. Expanding the knowledge about this type of injury and its preventive programs could be a key strategy to reduce the hamstring injury incidence. Thus, this review aimed to study the effectiveness of different preventive programs based on exercise interventions on reducing the hamstring injury incidence in athletes.

EVIDENCE ACQUISITION

An umbrella review was conducted through of PubMed/MEDLINE, Scopus, SPORTDiscus, Web of Science, Cochrane Library and Physiotherapy Evidence Database databases. The methodological quality of the included systematic reviews was assessed through the Assessing the Methodological Quality of Systematic Reviews 2 and the quality of the evidence was evaluated using the modified Grading of Recommendations Assessment, Development and Evaluation principles.

EVIDENCE SYNTHESIS

Eight systematic reviews and meta-analysis (40 primary studies) met the inclusion criteria, which included interventions based on eccentric strength, Nordic hamstring, proprioceptive training, stretching, FIFA11 and combined programs. From the qualitative synthesizes, three studies showed that eccentric-based training programs were effective; seventeen studies reported that Nordic hamstring-based programs were effective; three studies observed that stability training-based interventions were effective; two studies indicated that flexibility were effective; three studies claimed that FIFA11+based programs were effective; and two studies reported that combined programs were effective.

CONCLUSIONS

Exercise is a key strategy to reduce the hamstring injury incidence, being programs based on eccentric strength mainly by means of Nordic hamstring exercise, and on stability training, those programs which reported greater effectiveness.

A below-knee compression garment reduces fatigue-induced strength loss but not knee joint position sense errors

PURPOSE

We examined the possibility that wearing a below-knee compression garment (CG) reduces fatigue-induced strength loss and joint position sense (JPS) errors in healthy adults.

METHODS

Subjects (n = 24, age = 25.5 ± 4 years) were allocated to either one of the treatment groups that performed 100 maximal isokinetic eccentric contractions at 30°^-1 with the right-dominant knee extensors: (1) with (EXPCG) or (2) without CG (EXP) or to (3) a control group (CONCG: CG, no exercise). Changes in JPS errors, and maximal voluntary isometric contraction (MVIC) torque were measured immediately post-, 24 h post-, and 1 week post-intervention in each leg. All testing was done without the CG.

RESULTS

CG afforded no protection against JPS errors. Mixed analysis of variance (ANOVA) revealed that absolute JPS errors increased post-intervention in EXPCG and EXP not only in the right-exercised (52%, p = 0.013; 57%, p = 0.007, respectively) but also in the left non-exercised (55%, p = 0.001; 58%, p = 0.040, respectively) leg. Subjects tended to underestimate the target position more in the flexed vs. extended knee positions (75-61°: - 4.6 ± 3.6°, 60-50°: - 4.2 ± 4.3°, 50-25°: - 2.9 ± 4.2°), irrespective of group and time. Moreover, MVIC decreased in EXP but not in EXPCG and CONCG at immediately post-intervention (p = 0.026, d = 0.52) and 24 h post-intervention (p = 0.013, d = 0.45) compared to baseline.

CONCLUSION

Altogether, a below-knee CG reduced fatigue-induced strength loss at 80° knee joint position but not JPS errors in healthy younger adults.

Use of Fatigue Index as a Measure of Local Muscle Fatigability in Ryanodine Receptor Isoform-1-Related Myopathies

Introduction: Individuals affected with ryanodine receptor isoform-1-related myopathies (RYR1-RM) commonly experience fatigability in the quadriceps, which may limit physical function and potentially diminish quality of life. Fatigability, in RYR1-RM, results from skeletal muscle injury secondary to dysfunction of the major skeletal muscle Ca⁺⁺ channel. However, during fatigability testing, affected individuals did not always reach the point of local muscle fatigue as defined by a fatigue index (FATI) at 50% of peak torque. Surakka et al. compared three versions of FATI equations, which vary by the area under the force curve (AUC). By performing this comparison, they were able to determine the optimal equation in individuals with Multiple Sclerosis. Purpose: Using a similar comparison, we sought to identify the optimal FATI equation in the RYR1-RM population. Secondly, because local muscle fatigability might have an impact on independent living, this study also assessed change in local muscle fatigability over a 6-month time frame. Methods: Thirty participants were analyzed from the RYR1-RM natural history study and double-blind, placebo-controlled N-acetylcysteine (NAC) trial, NCT02362425. Twenty-seven had fatigability data, from isometric knee extension and flexion fatigability tests, available for the purpose of establishing a method for predicting FATI at 50% peak torque. For the natural history study, 30 participants were used to assess disease progression of local muscle fatigability achieved during the knee extension fatigability test, and 29 participants for the knee flexion fatigability test. Results: Surakka's equation 1, using the prediction approach, led to the smallest median error, the smallest square-root of uncorrected sum of squares, and the smallest average of the absolute value of the differences. No difference was observed in FATI at 50% peak torque between month 0 and month 6 for extension (p = 0.606) and flexion (p = 0.740). Conclusion: Surakka's equation 1, with the prediction approach, was found to be the most accurate for imputing values when fatigue was not reached during a sustained knee isometric fatigability test in RYR1-RM. Furthermore, when used to assess fatigability-based disease stability, local muscle fatigability, in this RYR1-RM population remained stable.

Is Remnant Preservation in Anterior Cruciate Ligament Reconstruction Superior to the Standard Technique? A Systematic Review and Meta-Analysis

Purpose

This is a systematic review and meta-analysis of current evidence that aims at comparing the clinical outcomes of remnant-preserving anterior cruciate ligament reconstruction (ACLR) and standard ACLR.

Methods

A systematic review of randomized controlled studies and cohort studies comparing remnant-preserving ACLR with standard ACLR with a minimum level of evidence of II was performed. Studies were included by strict inclusion and exclusion criteria. Extracted data were summarized as preoperative conditions, postoperative clinical outcomes, and postoperative complications. When feasible, meta-analysis was performed with RevMan5.3 software. Study methodological quality was evaluated with the modified Coleman methodology score (CMS).

Results

Eleven studies (n = 466 remnant-preserving and n = 536 standard) met the inclusion criteria. The mean modified CMS for all included studies was 85.8 (range: 77–92 on a 100-point scale). In total, 466 patients underwent remnant-preserving ACLR by 3 different procedures: standard ACLR plus tibial remnant tensioning (n = 283), selective-bundle augmentation (n = 49), and standard ACLR plus tibial remnant sparing (n = 134). Remnant-preserving ACLR provided a superior outcome of postoperative knee anterior stability (WMD = −0.42, 95% CI, −0.66, −0.17; P < 0.01) and Lysholm score (WMD = 2.01, 95% CI, 0.53 to 3.50; P < 0.01). There was no significant difference between the two groups with respect to second-look arthroscopy (OR = 1.38, 95% CI, 0.53, 3.62; P=0.51), complications (OR = 1.24 95% CI, 0.76, 2.02; P=0.39), International Knee Documentation Committee (IKDC) subject scores, IKDC grades, Lachman test, and pivot-shift test.

Summary/conclusion

Remnant-preserving ACLR promotes similar graft synovial coverage and revascularization to standard ACLR. Equivalent or superior postoperative knee stability and clinical scores were observed for remnant-preserving ACLR compared with standard ACLR. No significant difference in the total complication rate between the groups was evident.

Coupling Robot-Aided Assessment and Surface Electromyography (sEMG) to Evaluate the Effect of Muscle Fatigue on Wrist Position Sense in the Flexion-Extension Plane

Proprioception is a crucial sensory modality involved in the control and regulation of coordinated movements and in motor learning. However, the extent to which proprioceptive acuity is influenced by local muscle fatigue is obscured by methodological differences in proprioceptive and fatiguing protocols. In this study, we used high resolution kinematic measurements provided by a robotic device, as well as both frequency and time domain analysis of signals captured via surface electromyography (sEMG) to examine the effects of local muscle fatigue on wrist proprioceptive acuity in 16 physically and neurologically healthy young adults. To this end, participants performed a flexion/extension ipsilateral joint position matching test (JPM), after which a high-resistive robotic task was used to induce muscle fatigue of the flexor carpi radialis (FCR) muscle. The JPM test was then repeated in order to analyze potential changes in proprioceptive acuity. Results indicated that the fatigue protocol had a significant effect on movements performed in flexion direction, with participants exhibiting a tendency to undershoot the target before the fatigue protocol (−1.218°), but overshooting after the fatigue protocol (0.587°). In contrast, in the extension direction error bias values were similar before and after the fatigue protocol as expected (pre = −1.852°, post = −1.237°) and reflected a tendency to undershoot the target. Moreover, statistical analysis indicated that movement variability was not influenced by the fatigue protocol or movement direction. In sum, results of the present study demonstrate that an individual’s estimation of wrist joint displacement (i.e., error bias), but not precision (i.e., variability), is affected by muscular fatigue in a sample of neurologically and physically healthy adults.

Proprioception is not associated with lower extremity injuries in U21 high-level football players

Football is a contact sport with a significant risk of injury. Although proprioception is well studied in rehabilitation, little is known about the association between proprioception and the occurrence of sport injuries. The purpose of this study was to look into the association between ankle and knee proprioception and lower extremity injuries in young football players. Seventy-three football players from the highest U-21 league in Iran volunteered to participate in this study. Before the start of the 2017-2018 competitive season, joint position sense was measured at 30°, 60° and 90° knee flexion and at 10° and 15° ankle dorsiflexion, and inversion using the Biodex Isokinetic pro 4 system. The teams' medical staff recorded football-related lower extremity injuries. We used mixed effects Cox regression models to calculate hazard ratios (HRs) with 95% CIs, acknowledging the clustered data structure. Twenty-two players (30.1%) suffered one or more lower extremity injuries during the season. None of the proprioception measures examined was significantly associated with the risk of lower extremity injuries. Based on these results of our sample, joint position sense does not seem to be associated with lower extremity injuries in young male football players.

Revised Approach to the Role of Fatigue in Anterior Cruciate Ligament Injury Prevention: A Systematic Review with Meta-Analyses

BACKGROUND

Causes of anterior cruciate ligament (ACL) injuries are multifactorial. Anterior cruciate ligament injury prevention should thus be approached from a multifactorial perspective as well. Training to resist fatigue is an underestimated aspect of prevention programs given that the presence of fatigue may play a crucial role in sustaining an ACL injury.

OBJECTIVES

The primary objective of this literature review was to summarize research findings relating to the kinematic and kinetic effects of fatigue on single-leg landing tasks through a systematic review and meta-analysis. Other objectives were to critically appraise current approaches to examine the effects of fatigue together with elucidating and proposing an optimized approach for measuring the role of fatigue in ACL injury prevention.

METHODS

A systematic literature search was conducted in the databases PubMed (1978-November 2017), CINAHL (1992-November 2017), and EMBASE (1973-November 2017). The inclusion criteria were: (1) full text, (2) published in English, German, or Dutch, (3) healthy subjects, (4) average age ≥ 18 years, (5) single-leg jump landing task, (6) evaluation of the kinematics and/or kinetics of the lower extremities before and after a fatigue protocol, and (7) presentation of numerical kinematic and/or kinetic data. Participants included healthy subjects who underwent a fatigue protocol and in whom the effects of pre- and post-fatigue on three-dimensional lower extremity kinematic and kinetics were compared. Methods of data collection, patient selection, blinding, prevention of verification bias, and study design were independently assessed.

RESULTS

Twenty studies were included, in which four types of single-leg tasks were examined: the single-leg drop vertical jump, the single-leg drop landing, the single-leg hop for distance, and sidestep cutting. Fatigue seemed to mostly affect initial contact (decreased angles post-fatigue) and peak (increased angles post-fatigue) hip and knee flexion. Sagittal plane variables at initial contact were mostly affected under the single-leg hop for distance and sidestep cutting conditions whilst peak angles were affected during the single-leg drop jump.

CONCLUSIONS

Training to resist fatigue is an underestimated aspect of prevention programs given that the presence of fatigue may play a crucial role in sustaining an ACL injury. Considering the small number of variables affected after fatigue, the question arises whether the same fatigue pathways are affected by the fatigue protocols used in the included laboratory studies as are experienced on the sports field.

Return to play following anterior cruciate ligament reconstruction: incorporating fatigue into a return to play functional battery. Part A: treadmill running

Background

The risk of reinjury and other sequelae following anterior cruciate ligament reconstruction (ACLR) remains high. Lack of knowledge regarding factors contributing to these risks limits our ability to develop sensitive return to play (RTP) tests. Using a running task, we evaluate whether fatigue induces alterations in foot progression angle (FPA), a proposed biomechanical risk factor and could be used to enhance RTP test sensitivity.

Method

Transverse plane foot kinematics (FPA) were assessed for 18 post-ACLR subjects during a treadmill running task, before and after a generalised lower limb fatigue protocol. Subject’s contralateral limbs were used as a control group.

Results

A small but significant difference between FPA for ACLR and contralateral limbs was observed before but not after fatigue. When confounding variables were considered, there was a significant difference in FPA change between ACLR and contralateral limbs from the prefatigue to postfatigue state.

Conclusions

Following ACLR athletes may develop a knee-protective movement strategy that delays the progression of osteoarthritis in the ACL-injured knee. This may, however, increase the risk of ACL reinjury. Following the onset of fatigue this proposed movement strategy, and thus osteoarthritis protection, is lost.

Selective effect of static stretching, concentric contractions, and a balance task on ankle force sense

Proper ankle motor control is critical for balance in the human body during functional activities such as standing, walking, and running. Different exercise modalities are often performed during the same training session where earlier activities may influence later ones. The purpose of the current study was to determine the acute effects of different exercise modalities on ankle force sense. Seventeen subjects performed four different intervention protocols (static stretching, balance task, concentric contractions, and control) in random order. Each session comprised measurements before and after the intervention protocol of the force sense of the ankle plantar flexors (PF) and dorsal flexors (DF) at 10% and 30% of maximal voluntary isometric contraction (MVC). Absolute errors (AE) were calculated separately for each force level and muscle group. An overall PF error (PF-SUM = PF at 10%MVC + PF at 30%MVC), DF error (DF-SUM = DF at 10%MVC + DF at 30%MVC) and ankle error (PF-DF-SUM = PF-SUM + DF-SUM) were also calculated. The main effect of time generally revealed that ankle force sense was significantly reduced after static stretching (PF-DF-SUM: Pre: 6.11±2.17 Nm, Post: 8.03±3.28 Nm; p < 0.05), but no significant differences were observed for the concentric contractions (PF-DF-SUM: Pre: 6.01±1.97 Nm, Post: 6.50±2.28 Nm) and the balance task (PF-DF-SUM: Pre: 5.25±1.97 Nm, Post: 5.50±1.26 Nm). The only significant interaction was observed for the PF-DF-SUM (F = 4.48, p = 0.008) due to greater error scores after stretching (+31.4%) compared to the concentric (+8.2%), balance (+4.8%), and control (-3.5%) conditions. Based on these results, static stretching should not be performed before activities that require a high ankle force sense such as balance, coordination, and precision tasks.

Effects of table tennis multi-ball training on dynamic posture control

Background

Prior to the 2017 table tennis season, each participant performed the anterior, posteromedial, and posterolateral the star excursion balance test (SEBT) reach distances in a randomized order. The aim of this study was to assess the effects of table tennis multi-ball training and dynamic balance on performance measures of the SEBT for the male and female.

Methods

The limb lengths of the 12 table tennis athletes were measured bilaterally in the study. Besides warm-up end, the data of this study were recorded at a regular interval at approximately 16 min for the entire multi-ball training session, and they were defined as Phase I, Phase II, Phase II, respectively. The Borg rating of perceived exertion (RPE) scale was used to document the degree of physical strain.

Results

Reaching distances showed a decrease with training progression in all directions. Compared with the male table tennis athletes, the females showed poorer dynamic posture control, particularly when the free limb was considered with the right-leg stance toward posterolateral and posteromedial directions in phase I.

Discussion

This study suggests that during table tennis multi-ball training the male should have a regulatory protocol to compensate the deficit observed in phase II, but the females should be given the protocol in phase I.

Expansion Vibration Lipofilling: A New Technique in Large-Volume Fat Transplantation

BACKGROUND

Despite rapid growth, gluteal fat transplantation is an operation in search of science and a teachable technique. Long operating times, tedious syringe transfers, inability to shape the recipient site, and the risk of fat embolism all headline as impediments to clinical adoption of the procedure. Expansion vibration lipofilling is a syringe-free surgical strategy that is a logical extension of Separation, Aspiration, and Fat Equalization (SAFELipo). In expansion vibration lipofilling, there is simultaneous disruption of recipient-site connective tissue, internal expansion using exploded-tip cannulas, and backfilling of these spaces with roller pump-propelled fat.

METHODS

Two thousand four hundred nineteen consecutive cases of expansion vibration lipofilling fat transplantation to the buttocks were reviewed. Average follow-up was 12 months. The technique of expansion vibration lipofilling is dependent on the use of larger caliber cannulas attached to a roller pump and to an oscillatory power-assisted liposuction device, which is less labor-intensive, potentially allowing for better knowledge of cannula-tip location at all times during the procedure.

RESULTS

Operating times averaged 1 hour 40 minutes. The average volume of fat inserted was 1003 cc. Complications included donor-site seroma, infection, and one pulmonary embolism treated with anticoagulation. There were no cases of fat embolism or death.

CONCLUSIONS

Expansion vibration lipofilling is a new method for large-volume fat transplantation. Avoidance of fatal fat emboli demands a surgeon's complete knowledge of cannula tip location at all times during the procedure. Syringe-free, larger caliber, and less flexible cannulas, combined with techniques requiring less operator upper extremity effort resulting in less fatigue, may contribute to avoidance of this dreadful complication.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Training Load and Fatigue Marker Associations with Injury and Illness: A Systematic Review of Longitudinal Studies

Background

Coaches, sport scientists, clinicians and medical personnel face a constant challenge to prescribe sufficient training load to produce training adaption while minimising fatigue, performance inhibition and risk of injury/illness.

Objective

The aim of this review was to investigate the relationship between injury and illness and longitudinal training load and fatigue markers in sporting populations.

Methods

Systematic searches of the Web of Science and PubMed online databases to August 2015 were conducted for articles reporting relationships between training load/fatigue measures and injury/illness in athlete populations.

Results

From the initial 5943 articles identified, 2863 duplicates were removed, followed by a further 2833 articles from title and abstract selection. Manual searching of the reference lists of the remaining 247 articles, together with use of the Google Scholar ‘cited by’ tool, yielded 205 extra articles deemed worthy of assessment. Sixty-eight studies were subsequently selected for inclusion in this study, of which 45 investigated injury only, 17 investigated illness only, and 6 investigated both injury and illness. This systematic review highlighted a number of key findings, including disparity within the literature regarding the use of various terminologies such as training load, fatigue, injury and illness. Athletes are at an increased risk of injury/illness at key stages in their training and competition, including periods of training load intensification and periods of accumulated training loads.

Conclusions

Further investigation of individual athlete characteristics is required due to their impact on internal training load and, therefore, susceptibility to injury/illness.

Does Kinesiology tape counter exercise-related impairments of balance in the elderly?

BACKGROUND

Maintaining balance is an essential requirement for the performance of daily tasks and sporting activities, particularly in older adults to prevent falls and associated injuries. Kinesiology tape has gained great popularity in sports and is frequently used as a tool for performance enhancement. However, there is little research investigating its influence on balance.

RESEARCH QUESTION

The purpose of this study was to evaluate the effect of Kinesiology tape on dynamic balance, postural stability and knee proprioception after physical activity in healthy, older adults.

METHODS

Twelve physically active, healthy men aged 63-77 years performed the test on two separate days, with and without Kinesiology tape at the knee joint (prospective intervention with cross-over design). Dynamic balance during an obstacle-crossing task, postural stability in a single-leg stance test, and knee joint position sense as a measure of proprioception were examined before and after 30 min of downhill walking on a treadmill. The influences of taping condition and physical activity on all parameters were statistically tested using factorial ANOVAs.

RESULTS

Factorial ANOVA revealed significant time × taping condition interaction effects on all performance parameters (p < 0.05), indicating that the exercise-related changes in dynamic balance, postural stability and knee proprioception differed between the two taping conditions. The deterioration of performance was always greater when no tape was used.

SIGNIFICANCE

This study demonstrated that physical exercise significantly deteriorated dynamic balance, postural stability and knee proprioception in older men. These effects can be attenuated through the usage of Kinesiology tape. By preventing exercise-related impairments of balance, Kinesiology tape might help reduce the risk of sports-associated falls and associated injuries.

Staying Safe during Gluteal Fat Transplantation

Gluteal augmentation with fat transplantation is increasing in demand but has been associated with a concerning number of fatality reports. Despite these reports, various surgeons have safely performed gluteal fat transplantation on a large number of patients with no reported mortality. The important aspects of safely performing gluteal fat transplantation are reviewed. Proper patient selection, favorable instrumentation, patient positioning, proper technique, and knowledge of anatomy are critical to improving the safety of this procedure. Adherence to these key principles should allow a reduction in mortality from this procedure, which would safely allow its continued offering in the setting of increasingly high demand.

The effect of ankle tape on joint position sense after local muscle fatigue: a randomized controlled trial

Background

Ankle tape is widely used by athletes to prevent ankle sprain. Although there is growing evidence that ankle tape improve joint position sense, but yet it is not clear even if tape improve joint position sense after muscle fatigue, because fatigue impair joint position sense and raise the risk of ankle sprain. The aim of this study is to examine the effect of ankle tape on joint position sense after local muscle fatigue.

Method

This trial is a randomized controlled trial. 34 healthy subjects participated in this trial. Subjects were randomized distributed into two groups: with tape and without tape. Active and passive absolute error and variable error mean values for two target positions of the ankle joint (15° inversions and inversion minus 5°) before and after fatigue protocol consisted of 30 consecutive maximal concentric/concentric contractions of the ankle evertors and invertors. In this trail joint position sense for all subjects was assessed using The Biodex System isokinetic dynamometer 3, this system is used also for fatigue protocol.

Results

For the variable error (VE), significant mean effect was found for active joint position sense in 15° of inversion after muscle fatigue (P < 0, 05). It was a significant decrease in the work in the last third of inversion detected (P < 0, 05). There was no significant main effect found for fatigue index of eversion.

Conclusion

Ankle tape can improve joint position sense at the fatigue session when joint position sense becomes worse. As a result, ankle tape may be useful to prevent ankle sprain during playing sports. We suggest athletes and individuals at risk of ankle sprain to apply taping before high-load activity.

Trial registration

The study was retrospectively registered on the ISRCTN registry with study ID ISRCTN30042335 on 12th December 2017.

Recalibration of hand position sense during unconscious active and passive movement

Precise knowledge of one's limbs' position in space is fundamental for goal-directed action. The brain's representation of the body in space is thought to be generated through a process of multisensory integration of visual, tactile and proprioceptive signals. In this study, we devised a setup that allowed us to displace participants' right hand without their subjective awareness. We accomplished this task by instructing the participants to view a live video feed of their hand from the first-person perspective. In the active condition, we used a sensorimotor illusion that caused the participants to actively but unknowingly displace their unseen right hand to a location 8 cm lateral to the image of their hand. In the passive condition, we mechanically displaced the participants' hand-at a slow, unnoticeable velocity-to the same location. We found that during active displacement, the participants indicated that the location of their hand was closer to the digital image of the hand rather than the veridical location of the hand, as compared with the passive condition, in which the participants indicated that the locations of their hand were closer to the actual location. These results indicated that, compared with passive displacement, active movements cause greater recalibration of the hand's spatial position and that the boosted spatial recalibration of hand position sense in the active task is driven by error-based sensorimotor corrections. These results have bearing on the perceptual mechanisms of recalibration of perceived limb location.

Eccentric Exercise, Kinesiology Tape, and Balance in Healthy Men

CONTEXT

  Deficits in balance have been identified as a possible risk factor for knee injuries in athletes. Despite a lack of evidence for its effectiveness, kinesiology tape (KT) is widely used to prevent knee injuries.

OBJECTIVE

  To investigate the influence of KT at the knee joint on balance ability in healthy men after eccentric exercise.

DESIGN

  Crossover study.

SETTING

  University laboratory.

PATIENTS OR OTHER PARTICIPANTS

  Twelve young men with no history of lower limb injury volunteered for the study (age = 23.3 ± 2.6 years). All participants were students enrolled in a sports science program.

INTERVENTION(S)

  Participants performed the balance test with and without KT at the knee joint on 2 separate days.

MAIN OUTCOME MEASURE(S)

  The ability to maintain balance was assessed during a single-legged-stance test using a computerized balance-stability test system. The test was performed before and after 30 minutes of downhill walking on a treadmill.

RESULTS

  Eccentric exercise resulted in a deterioration of balance ability, which was attenuated by the use of KT. Further analyses revealed that the effectiveness of KT depended on the participant's balance status, with the preventive effect being greater in participants presenting with poorer baseline balance ability.

CONCLUSIONS

  Applied to the knee joint, KT counteracted the exercise-related deterioration of balance ability observed when no tape was used. Participants presenting with below-average balance ability received more benefit from KT. By preventing exercise-related impairment of balance ability, KT might help to reduce the risk of sport-associated knee injuries.

Muscle Activation During Landing Before and After Fatigue in Individuals With or Without Chronic Ankle Instability

CONTEXT

Ankle instability is a common condition in physically active individuals. It often occurs during a jump landing or lateral motion, particularly when participants are fatigued.

OBJECTIVE

To compare muscle activation during a lateral hop prefatigue and postfatigue in individuals with or without chronic ankle instability (CAI).

DESIGN

Cross-sectional study.

SETTING

Sports medicine research laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 32 physically active participants volunteered for the study. Sixteen participants with CAI (8 men, 8 women; age = 20.50 ± 2.00 years, height = 172.25 ± 10.87 cm, mass = 69.13 ± 13.31 kg) were matched with 16 control participants without CAI (8 men, 8 women; age = 22.00 ± 3.30 years, height = 170.50 ± 9.94 cm, mass = 69.63 ± 14.82 kg) by age, height, mass, sex, and affected side.

INTERVENTION(S)

Electromyography of the tibialis anterior, peroneus longus, gluteus medius, and gluteus maximus was measured before and after a functional fatigue protocol.

MAIN OUTCOME MEASURE(S)

Activation of 4 lower extremity muscles was measured 200 milliseconds before and after landing from a lateral hop.

RESULTS

We observed no interactions. The group main effects for the peroneus longus demonstrated higher muscle activation in the CAI group (52.89% ± 11.36%) than in the control group (41.12% ± 11.36%) just before landing the lateral hop (F_1,30 = 8.58, P = .01), with a strong effect size (d = 1.01). The gluteus maximus also demonstrated higher muscle activation in the CAI group (45.55% ± 12.08%) than in the control group (36.81% ± 12.08%) just before landing the lateral hop (F_1,30 = 4.19, P = .049), with a moderate effect size (d = 0.71). We observed a main effect for fatigue for the tibialis anterior, with postfatigue activation higher than prefatigue activation (F_1,30 = 7.45, P = .01). No differences were present between groups for the gluteus medius.

CONCLUSIONS

Our results support the presence of a centralized feed-forward neuromuscular alteration in patients with CAI, not only in the ankle-joint muscles but also in the proximal hip muscles. These results may have implications for rehabilitation programs in these patients.

Different Effect of Local and General Fatigue on Knee Joint Stiffness

PURPOSE

This study aimed to investigate the influence of locally and generally induced fatigue on the stiffness properties of the knee joint.

METHODS

Twenty-two male (24.9 ± 4.5 yr, 1.78 ± 0.06 m, 75.4 ± 6.4 kg, 23.9 ± 1.8 kg·m) and 18 female (21.1 ± 1.5 yr, 1.66 ± 0.05 m, 63.4 ± 6.5 kg, 22.9 ± 2.5 kg·m) amateur athletes participated. Peak torque (PT) of the knee extensor musculature, muscle stiffness (MS) of the vastus lateralis, and musculoarticular stiffness (MAS) of the knee joint were assessed pre- and postlocally and generally induced fatigue (undertaken on two separate days with a 1-wk interval).

RESULTS

Males were characterized by higher values of MAS, relaxed and contracted MS, normalized PT (PT/body mass), and normalized MAS (MAS/external load) irrespective of time point (P < 0.05).

LOCALLY INDUCED FATIGUE

Contracted MS increased more (P < 0.01) and normalized PT decreased more (P = 0.03) in males than in females postfatigue. Significant increases occurred in MAS in females (P = 0.01); relaxed MS (males, P < 0.001; females, P < 0.001), contracted MS (males, P < 0.001; females, P = 0.04), and normalized MAS (males, P = 0.001; females, P = 0.01) in both sexes; and normalized contracted MS (contracted MS/external load) in males (P < 0.001). Normalized PT decreased significantly in males (P < 0.01) postfatigue.

GENERALLY INDUCED FATIGUE

Contracted MS (P = 0.01) and MAS (P = 0.05) decreased significantly in males post-fatigue.

CONCLUSION

The stiffness properties of the knee joint are influenced by locally and generally induced fatigue, with different responses being observed in males and females.

Effects of Volitional Spine Stabilization and Lower Extremity Fatigue on Trunk Control During Landing in Individuals With Recurrent Low Back Pain

STUDY DESIGN

Controlled laboratory study.

BACKGROUND

Recurrent low back pain (LBP) and neuromuscular fatigue are independently thought to increase the risk of spine injury. Volitional preemptive abdominal contraction (VPAC) is thought to improve lumbar spine and pelvis control in individuals with recurrent LBP. The effects of VPAC on fatigued landing performance in individuals with recurrent LBP are unknown.

OBJECTIVES

To determine the effects of VPAC and lower extremity fatigue on trunk control during landing in a population of individuals with recurrent LBP.

METHODS

Thirty-two recurrent LBP (mean ± SD age, 21.2 ± 2.7 years) and 33 healthy (age, 20.9 ± 2.3 years) subjects performed 0.30-m drop-jump landings with and without VPAC and fatigue. Trunk, pelvis, and hip biomechanical and electromyographic variables were obtained using 3-D motion capture. Hypotheses were tested using analysis of variance.

RESULTS

Volitional preemptive abdominal contraction resulted in significantly earlier muscle onsets across all muscles, with and without fatigue, in both groups (mean ± SD, 0.058 ± 0.019 seconds earlier; P≤.001) and altered lumbar lateral flexion (1.4° ± 14.8° greater right lateral flexion; P = .002). Fatigue significantly delayed muscle onsets (0.040 ± 0.014 seconds later; P≤.001) and altered pelvic obliquity (1.4° ± 11.0° greater; P≤.001) and trunk side flexion (2.0° ± 14.8° less; P≤.001). The recurrent LBP group exhibited delayed muscle onsets (0.039 ± 0.031 seconds later; P≤.004) and 4.2° less hip abduction at initial contact (P≤.008) in comparison to healthy controls.

CONCLUSION

Volitional preemptive abdominal contraction decreases some of the detrimental effects of fatigue on landing biomechanics and thus may reduce spine injury risk in individuals with recurrent LBP.