Changes in the force-time curve during a repeat power ability assessment using loaded countermovement jumps.

Background: Repeat power ability (RPA) assessments traditionally use discrete variables, such as peak power output, to quantify the change in performance across a series of jumps. Rather than using a discrete variable, the analysis of the entire force-time curve may provide additional insight into RPA performance. The aims of this study were to (1) analyse changes in the force-time curve recorded during an RPA assessment using statistical parametric mapping (SPM) and (2) compare the differences in the force-time curve between participants with low and high RPA scores, as quantified by traditional analysis. Materials and Methods: Eleven well-trained field hockey players performed an RPA assessment consisting of 20 loaded countermovement jumps with a 30% one repetition maximum half squat load (LCMJ20). Mean force-time series data was normalized to 100% of the movement duration and analysed using SPM. Peak power output for each jump was also derived from the force-time data and a percent decrement score calculated for jumps 2 to 19 (RPA%dec). An SPM one-way ANOVA with significance accepted at α = 0.05, was used to identify the change in the force-time curve over three distinct series of jumps across the LCMJ20 (series 1 = jumps 2-5, series 2 = jumps 9-12 and series 3 = jumps 16-19). A secondary analysis, using an independent T-test with significance accepted at p < 0.001, was also used to identify differences in the force-time curve between participants with low and high RPA%dec. Results: Propulsive forces were significantly lower (p < 0.001) between 74-98% of the movement compared to 0-73% for changes recorded during the LCMJ20. Post hoc analysis identified the greatest differences to occur between jump series 1 and jump series 2 (p < 0.001) at 70-98% of the movement and between jump series 1 and jump series 3 (p < 0.001) at 86-99% of the movement. No significant differences were found between jump series 2 and jump series 3. Significant differences (p < 0.001) in both the braking phase at 44-48% of the jump and the propulsive phase at 74-94% of the jump were identified when participants were classified based on low or high RPA%dec scores (with low scores representing an enhanced ability to maintain peak power output than high scores). Conclusion: A reduction in force during the late propulsive phase is evident as the LCMJ20 progresses. SPM analysis provides refined insight into where changes in the force-time curve occur during performance of the LCMJ20. Participants with the lower RPA%dec scores displayed both larger braking and propulsive forces across the LCMJ20 assessment.

Identifying clinically meaningful muscle power enhancements and their functional correlates in hospitalized older patients.

BACKGROUND: This study aimed to determine the threshold of muscle power and strength enhancements that lead to functional gains after exercise intervention in an acute care unit. METHODS: A total of 302 older patients (intervention: 169, control: 133) from two randomized clinical trials were included (mean age 86.7 years). We measured maximal strength (1RM) and muscle power via a velocity transducer during leg press exercise at 30% and 60% of 1RM. A multicomponent exercise program, including power training, balance, and gait exercises performed over 3 to 6 consecutive days, served as the intervention. We used an anchor-based method to correlate muscle function increases with the Short Physical Performance Battery (SPPB) and gait velocity (GVT) to define clinically meaningful improvements (CMI). RESULTS: In the intervention group, marked differences were found in maximal power at 30% of 1RM between SPPB responders and non-responders (relative 83.5% vs. 34.8%; absolute 33.0 vs. 12.8 W; P<0.05) and at 60% of 1RM (relative 61.1% vs. 22.4%; P<0.05). GVT responders demonstrated significantly greater improvements in both relative and absolute maximal power than non-responders at both 30% and 60% of 1RM (P<0.05), as well as greater absolute 1RM gains (21.2 vs. 15.2 kg, P<0.05). CMI for muscle power based on SPPB and GVT ranged from 30.2% to 48.7%, whereas for 1RM, it was 8.2% based on GVT. CONCLUSION: Muscle power gains were most notable in patients with improvements in the SPPB and GVT, highlighting the critical role of muscle power in functional recovery in these patients.

The Accuracy and Reliability of the Power Measurements of the TACX Neo 2T Smart Trainer and Its Agreement against the Garmin Vector 3 Pedals.

The power output in cycling is one of the most important factors for athletes and coaches. The cycling community has several commercial gears that can be used. One of the most used is the TACX Neo 2T (TN2T) smart trainer. The objective of this study was to investigate the metrological proprieties of the TN2T (accuracy and reliability), as well as its agreement with the Garmin Vector 3 (GV3) pedals at different power stages. The sample consisted of ten regional-level cyclists with a mean age of 45.6 ± 6.4 years, who regularly participated in regional and national competitions. Residual relative differences were found between the two devices. Both devices showed good reliability with coefficients of variation and intraclass correlation coefficients ranging from 0.03% to 0.15% and from 0.731 to 0.968, respectively. Independent samples t-test comparison between devices showed no significant differences in all power stages (p > 0.05). Bland-Altman plots showed that more than 80% of the plots were within the 95% confidence intervals in all power stages. The present data showed that there were non-significant differences between the two devices at power stages between 100 W and 270 W, with a strong agreement. Therefore, they can be used simultaneously.

Examining the impact of differing caffeine dosages in conjunction with plyometric training on physiological adaptations in basketball players.

The aim of the current study was to investigate the effects of ingesting different dosages of caffeine (CAF) prior to plyometric jump training (PJT) on sport-related performance and physiological parameters in male basketball players. Twenty-four young athletes were randomly divided into 3 groups and performed 6 weeks of PJT while consuming 3 mg·kg-1 of body mass caffeine (CAF3, n = 8), 6 mg·kg-1 body mass caffeine (CAF6, n = 8) or placebo (PL; n = 8) one hour prior to each training session. Before and after the 6-week PJT, the players were evaluated for field-based basketball-specific performance measures (vertical jump, 20-m sprint, Illinois change of direction speed [CODS], and maximal strength) and lab-based physiological (aerobic capacity and anaerobic power) parameters. CAF3, CAF6, and PL groups demonstrated significant improvements in vertical jump (ES = 1.07, 1.45, and 1.1, respectively), 20-m sprint (ES = - 0.50, - 0.61, and - 0.36), change of direction performance (ES = - 1.22, - 1.26, and - 1.09), maximal strength (ES = 1.68, 2.29, and 1.17), maximum oxygen uptake (V̇O2max) (ES = 1.09, 1.59, and 0.92), and peak (ES = 1.82, 1.85, and 0.82) and average power output (ES = 1.39, 1.32, and 1.07) after 6 weeks of training. Comparative analysis of individual adaptive responses to training indicated that the CAF6 led to insignificantly greater effects in vertical jump (ES = 1.45), maximal strength (ES = 2.29), and V̇O2max (ES = 1.59) with lower residuals in individual changes and lower coefficient of variations (CV) in mean group changes. Regarding sprint and CODS performance, both experimental groups indicated similar changes, residuals in individual changes, and CVs in mean group changes. Overall, consuming 6 mg·kg-1 body mass caffeine induces superior adaptations in aerobic fitness, anaerobic power, and sport-specific performance measures, with lower inter-individual variability in the adaptations and more homogenized changes over the training period.

Effects of Eccentric Speed during Front Squat Conditioning Activity on Post-activation Performance Enhancement of Hip and Thigh Muscles.

The phenomenon of post-activation performance enhancement plays an unidentified role in movement eccentric speed and individual muscle group responses. Therefore, this study aimed to determine whether the loaded front squat (FSq) speed of the eccentric phase would influence the post-activation performance enhancement effect and whether the FSq would elicit similar performance enhancement of knee flexion, knee extension, hip flexion, and hip extension muscles. Twenty resistance-trained handball players performed the FSq under maximum eccentric-concentric speed and 2-s eccentric speed (only the eccentric phase performed), while pre- and post-front squat countermovement jump, knee, and hip isokinetic flexion/extension performance were tested. The FSq conditioning activity was performed in a single set of three repetitions with either 90% (maximum eccentric-concentric speed) or 120% (2-s eccentric speed) of one repetition maximum, and post-performance was measured 4-12 min after the FSq. Athletes randomly changed the FSq eccentric speed and tested the hip or knee isokinetic flexion/extension strength at 180°/s. ANOVA showed that the rate of force development during the jump increased (Cohen d = 0.59-0.77) with no differences between 2-s eccentric and maximum speed eccentric protocols. Isokinetic strength increased after the 2-s eccentric FSq in hip extension (d = 0.76-0.86), knee flexion (d = 0.74-0.88), and hip flexion (d = 0.82), with no differences in knee extension strength. After maximum eccentric-concentric speed, isokinetic strength increased in hip extension (d = 1.25). In conclusion, the FSq conditioning activity enhances hip extensors' performance more than knee extensors' performance. Different eccentric types of muscle action during a conditioning activity alter the level of local muscle enhancement.

Long-Term Effects of a 6-Week Power-Based Resistance Training and Fast Walking Interval Training Program on Physical Function, Muscle Power, Disability, and Frailty in Pre-Frail and Frail Older Adults.

INTRODUCTION: Concurrent training has been shown to be a beneficial approach to improve overall health status in older adults. However, little is known about the adaptations of this type of training in the long term (i.e., after cessation of exercise), even less in older people affected by frailty syndrome. Therefore, this study aimed (i) to assess the effects of a 6-week concurrent training program composed of power-oriented resistance training and fast walking interval training on physical function, muscle power, disability in activities of daily living and frailty in pre-frail and frail older people, and (ii) to assess the effects of a 6-month detraining period on these outcomes. METHODS: A total of 59 pre-frail and frail older adults (>75 years old; Frailty Phenotype >1) were allocated into intervention (INT; n = 32; 81.8 years; 21 women) or control (CON; n = 27; 82.5 years; 19 women) groups. Primary outcomes of this study were Short Physical Performance Battery (SPPB), relative sit-to-stand (STS) power, Barthel index, Lawton scale and Frailty Phenotype. Assessments were performed at baseline (PRE), after the concurrent training programme (POST) and after 6 months of follow-up (DET) in both groups. Mixed model repeated measures ANOVA with Bonferroni's post hoc tests was used. RESULTS: Immediately after the intervention (∆ = POST-PRE), INT improved SPPB (∆ = 3.0 points; p < 0.001), relative STS power (∆ = 0.87 W·kg-1; p < 0.001) and reduced their frailty levels (∆ = -1.42 criteria; p < 0.001), while no changes were observed in CON. After 6 months of detraining (∆ = DET-PRE), INT showed higher SPPB (∆ = 2.2 points; p < 0.001), higher relative STS power (∆ = 0.73 W·kg-1; p < 0.001) and lower frailty (∆ = -1.24 criteria; p < 0.001) values than those reported at baseline, which were significantly different than those reported by CON. Both, Barthel index and Lawton scale values were not modified during the study in either group. CONCLUSIONS: The 6-week concurrent training program improved physical function, muscle power and reduced frailty in pre-frail and frail older people and these improvements were maintained above baseline levels after 6 months of detraining. However, due to the individual variability found, future studies of long-term responders versus non-responders in frail populations are required.

Therapeutic validity and replicability of power training interventions in older adults: A review using the TIDieR checklist and CONTENT scale.

Background: Randomized controlled trials (RCTs) indicate that power training has the ability to improve muscle power and physical performance in older adults. However, power training definitions are broad and previously-established criteria are vague, making the validity and replicability of power training interventions used in RCTs uncertain. Objective: The aim of this review was to assess whether the power training interventions identified in a previous systematic review (el Hadouchi 2022) are fully described, therapeutically valid, and meet our proposed criteria for power training. Design: Review. Methods: Power training interventions used in older adults, previously-identified in a systematic review, were assessed. The completeness of intervention descriptions was evaluated using the Template for Intervention Description and Replication (TIDieR), and therapeutic validity was evaluated using the CONTENT scale in combination with a set of criteria specific for power training. Results: None of the power training interventions were fully described or met the CONTENT scale's criteria for therapeutic validity. Five out of 14 interventions (35.7 %) met all specific power training criteria. Conclusions: Power training interventions used in RCTs comparing power training to strength training are poor to moderately described, may not be therapeutically valid, and may not reflect the construct of power training. This makes it difficult for clinicians or researchers to apply or replicate power training interventions reported in RCTs, and begs the question whether the true effects of power training have been estimated.

Effect of lower-extremity muscle power training on muscle strength, balance function and walking ability in older adults with heart failure: a randomized controlled trial.

PURPOSE: This study investigated the combined effect of lower-extremity muscle power training and regular cardiac rehabilitation on muscle strength, balance function, and walking ability of older adults with heart failure. METHODS: Thirty-one patients, comprising 17 males and 14 females, aged between 66 and 89 years and diagnosed with non-severe heart failure, were randomly assigned to either the intervention group (n = 15) or control group (n = 16). Both groups participated in a 12-week regular rehabilitation program, with the intervention group receiving additional lower-extremity muscle power training. Various outcome measures, including muscle strength (the five-times-sit-to-stand test and knee extensor peak torque), balance function (Berg balance scale and functional reach test), and walking ability (4-m walk and Timed Up-and-Go tests) were assessed at baseline and 12 weeks after the intervention. RESULTS: Of the 31 participants, 27 completed the study protocol. The intervention group demonstrated significantly greater improvement in the five-times-sit-to-stand test time, indicating enhanced lower-extremity muscle power compared to the control group. Both groups showed significant differences in the Berg balance scale, functional reach test, 4-m walk test, and Timed Up-and-Go test between baseline and 12 weeks. However, the effect sizes for the changes during the study period were larger in the intervention group (d = 0.74-1.19) than the control group (d = 0.57-0.96). CONCLUSION: Combining lower-extremity muscle power training with regular cardiac rehabilitation may lead to additional improvements in muscle function for older adults with heart failure, resulting in enhanced dynamic balance and walking ability. TRIAL REGISTRATION NUMBER/DATE OF REGISTRATION: UMIN000032087/April 4, 2018.

Effects of short-term multicomponent exercise intervention on muscle power in hospitalized older patients: A secondary analysis of a randomized clinical trial.

BACKGROUND: Bed rest during hospitalization can negatively impact functional independence and clinical status of older individuals. Strategies focused on maintaining and improving muscle function may help reverse these losses. This study investigated the effects of a short-term multicomponent exercise intervention on maximal strength and muscle power in hospitalized older patients. METHODS: This secondary analysis of a randomized clinical trial was conducted in an acute care unit in a tertiary public hospital. Ninety (39 women) older patients (mean age 87.7 ± 4.8 years) undergoing acute-care hospitalization [median (IQR) duration 8 (1.75) and 8 (3) days for intervention and control groups, respectively]) were randomly assigned to an exercise intervention group (n = 44) or a control group (n = 46). The control group received standard care hospital including physical rehabilitation as needed. The multicomponent exercise intervention was performed for 3 consecutive days during the hospitalization, consisting of individualized power training, balance, and walking exercises. Outcomes assessed at baseline and discharge were maximal strength through 1 repetition maximum test (1RM) in the leg press and bench press exercises, and muscle power output at different loads (≤30% of 1RM and between 45% and 55% of 1RM) in the leg press exercise. Mean peak power during 10 repetitions was assessed at loads between 45% and 55% of 1RM. RESULTS: At discharge, intervention group increased 19.2 kg (Mean Δ% = 40.4%) in leg press 1RM [95% confidence interval (CI): 12.1, 26.2 kg; P < 0.001] and 2.9 kg (Mean Δ% = 19.7%) in bench press 1RM (95% CI: 0.6, 5.2 kg; P < 0.001). The intervention group also increased peak power by 18.8 W (Mean Δ% = 69.2%) (95% CI: 8.4, 29.1 W; P < 0.001) and mean propulsive power by 9.3 (Mean Δ% = 26.8%) W (95% CI: 2.5, 16.1 W; P = 0.002) at loads ≤30% of 1RM. The intervention group also increased peak power by 39.1 W (Mean Δ% = 60.0%) (95% CI: 19.2, 59.0 W; P < 0.001) and mean propulsive power by 22.9 W (Mean Δ% = 64.1%) (95% CI: 11.7, 34.1 W; P < 0.001) at loads between 45% and 55% of 1RM. Mean peak power during the 10 repetitions improved by 20.8 W (Mean Δ% = 36.4%) (95% CI: 3.0, 38.6 W; P = 0.011). No significant changes were observed in the control group for any endpoint. CONCLUSIONS: An individualized multicomponent exercise program including progressive power training performed over 3 days markedly improved muscle strength and power in acutely hospitalized older patients.

Cost-Consequences Analysis Following Different Exercise Interventions in Institutionalized Oldest Old: A Pilot Study of a Randomized Clinical Trial.

OBJECTIVES: to investigate the effects of two different exercise interventions on cost of care, functional capacity, falls occurrence, muscle strength, and executive function in institutionalized oldest old. DESIGN: A pilot study of a randomized clinical trial investigating 12 months of two exercise interventions compared to a usual care group in oldest old residents of a nursing home. SETTING AND PARTICIPANTS: 69 older patients (mean age 89.4 ±5.1 years) completed the full baseline and post intervention measurements. Participants were randomly allocated into multicomponent exercise group (MG, n=23), calisthenics group (CALG, n = 23), and usual care group (UCG, n=23). METHODS: Primary outcome was individual cost of care, and secondary outcomes included different physical and cognitive functioning tests, as well as number of falls. RESULTS: MG reduced the cost of care compared to the pre-intervention period, with the greatest difference from baseline achieved in month 12 [mean change 95% confidence interval (CI)=-330.43 (-527.06, -133.80), P=0.006], while UCG increased this outcome, with the greatest difference from baseline observed in month 12 [mean change (95%CI)=300.00 (170.27, 429.72), P=0.013]. In addition, MG significantly improved SPPB score [mean change (95% CI) = 1.21 (0.55, 1.88), P<0.001], whereas the UCG exhibited a decline in scores [mean change (95% CI) = -1.43 (-1.90, -0.97), P<0.001]. Moreover, MG group demonstrated an improvement in the number of falls [mean change (CI 95%) = -1.0 (-1.73, -0.27), P=0.003], while no significant changes were observed in UCG. Additionally, MG exhibited a significant increase in the handgrip strength (HGS) and leg press strength (P<0.001), while a decrease was observed in UCG (P<0.001). No significant changes were observed in the CALG. CONCLUSIONS AND IMPLICATIONS: a one-year multicomponent exercise intervention reduced the cost of care, improved functional capacity and muscle strength, as well as reduced falls in institutionalized oldest old.

The Percentage of Total and Regional Fat Is Negatively Correlated with Performance in Judo.

This study investigated the associations between total and regional body composition with performance in the special judo fitness test (SJFT), as well as strength and power tests (countermovement vertical jump-CMJ, squat jump-SJ, plyometric push-up-PPU, and force push-up-FPU). Twenty-three high-level judo athletes participated in this study. Initially, they underwent dual-energy X-ray absorptiometry, after which they performed the CMJ, SJ, PPU, and FPU tests. On another day, the SJFT was carried out. Correlations were tested using Pearson's test. The performance in the SJFT was correlated with the total and arm %fat mass (r = -0.759), torso fat mass (r = -0.802), torso %fat mass (r = -0.822) and in the lower limb regions with the leg fat mass (r = -0.803) and leg %fat (r = -0.745). In the strength and power tests, there were also negative correlations observed between regional fat and performance. There was a negative correlation between the percentage of total fat and performance in the SJFT (r = -0.824), SJ (r = -0.750), CMJ (r = -0.742), PPU (r = -0.609), and FPU (r = -0.736). Fat, both total fat and regional fat in the arms, torso, and legs, is strongly correlated with a poor performance in the SJFT and poor strength and power.

High-velocity resistance training improves executive function in mobility-limited older adults.

OBJECTIVES: To examine the effect of high-velocity resistance training (HVRT) on the executive function of middle-aged and older adults with and without mobility limitations. METHODS: Participants (n = 41, female: 48.9%) completed a supervised 12-week HVRT intervention (2 sessions/week; at 40-60% of one-repetition maximum). The sample included 17 middle-aged adults (40-55 years); 16 older adults (>60 years) and 8 mobility-limited older adults (LIM). Executive function was assessed before and after the intervention period and was reported as z-scores. Maximal dynamic strength, peak power, quadriceps muscle thickness, maximal isometric voluntary contraction (MVIC), and functional performance were also measured pre and post intervention. Training-related adaptations in cognitive measures were calculated using a Generalized Estimating Equation model. RESULTS: HVRT improved executive function in LIM (adjusted marginal mean differences [AMMD]: 0.21; 95%CI: 0.04, 0.38; p = 0.040) although no effect on middle-aged (AMMD: 0.04; 95%CI: -0.09; 0.17; p = 0.533) and older (AMMD: -0.11; 95%CI: -0.25; 0.02; p = 0.107) participants was observed. Improvements in maximal dynamic strength, peak power, MVIC, quadriceps muscle thickness, and functional performance were all associated with changes in executive function, and changes in the first four also seem to mediate the association between changes in functional performance and executive function. CONCLUSIONS: HVRT-induced improvement in executive function of mobility-limited older adults were mediated by changes in lower-body muscle strength, power, and muscle thickness. Our findings reinforce the relevance of muscle-strengthening exercises to preserve cognition and mobility in older adults.

Effect of power training on rate of torque development and spatiotemporal gait parameters post stroke.

BACKGROUND: Maximizing independence and function post-stroke are two common therapy goals. Rate of torque development in lower-extremity muscles was recently reported to be associated with walking speed; however, trainability and subsequent effect on gait is unknown. This study aimed to determine effect of power training on paretic and non-paretic limb torque parameters, spatiotemporal gait parameters, and walking speed in chronic stroke survivors. METHODS: Individuals with chronic stroke (n = 22; 7 females; 62.7 ± 8.8 yrs) completed 24 progressive power-training sessions over 8 weeks with pre and post assessments. Knee extensor strength was assessed via dynamometry with torque parameters measured from maximal voluntary isometric contractions. Gait speed and spatiotemporal gait parameters were assessed via an instrumented gait mat, and a 6-min walk test was performed. FINDINGS: Rate of torque development at 200 ms and peak torque improved 58.6% and 14.1%, respectively, in the quadricep of the paretic limb (p < 0.05); conversely the non-paretic limb was unchanged. On average, self-selected walking speed, fastest-comfortable walking speed, and 6-min walk test improved 21.7%, 21.1%, and 19.5%, respectively (all p < 0.05). Change in torque development at 100 ms in the quadricep of the non-paretic limb was positively associated with improvements in self-selected and fastest-comfortable walking speeds (both r = 0.70, p < 0.05) and 6-min walk (r = 0.78, p < 0.001). INTERPRETATIONS: These findings suggest power training may be an effective intervention for improving torque development in the quadricep of the paretic limb in individuals with chronic stroke. Further research to explore utility and mechanistic aspects of force development for gait function in chronic stroke survivors is warranted.

Effect of power training on locomotion capacities in children with cerebral palsy with GMFCS level III-IV.

PURPOSE: Power training (PT) is a promising training modality to improve functional abilities in children with cerebral palsy (CP). This study aimed to implement PT in an adapted school and to assess its effect on locomotion capacities in children with Gross Motor Function Classification System (GMFCS) level III-IV. MATERIALS AND METHODS: Nine children with CP (GMFCS level III-IV) were trained three times/week for 12 weeks. The training sessions took place during the 50-minute physical activity classes and included high intensity exercise. The outcome measures were the performance on the 10-meter comfortable and fast walking tests, the 50-meter sprint test (50M-ST), and the energy expenditure index (EEI). RESULTS: Participants spent 12 ± 7 and 7 ± 9 min per session at an intensity superior to 40% and 60% of the heart rate reserve, respectively. Performance in the 10-meter walking test (13.5 ± 7.8 to 9.9 ± 4.6 s, p < 0.05), the 10-meter fast walking test (8.8 ± 3.1 to 7.0 ± 3.2 s, p < 0.05), the 6-minute walking exercise (199.0 ± 48.6 to 316.6 ± 107.2 m, p < 0.05), and in 50M-ST (53.8 ± 29.5 to 42.3 ± 16.2 s, p < 0.05) increased after training. The EEI was reduced after training (p = 0.01), resulting in a more efficient gait. CONCLUSIONS: PT was successfully implemented in children with CP with GMFCS level III-IV. Results suggest that PT increases walking capacities.Implications for rehabilitationPower training (PT) is feasible with children with bilateral cerebral palsy with GMFCS level III and IV.Physical education course in specialist school is a valuable environment to implement PT in children with poor gross motor function.Power training results in locomotion capacities improvement.

The effects of power exercises on body structure and function, activity and participation in children with cerebral palsy: an ICF-based systematic review.

PURPOSE: To systematically review the literature for evidence of effectiveness of power exercises on physical, physiological, and functional outcomes in children and adolescents with cerebral palsy (CP). MATERIALS AND METHODS: Methodological quality and evidence synthesis were assessed with using the Cochrane Risk of Bias (RoB) Tools and Modified Bakker Scale. Using the International Classification of Functioning (ICF), outcome measures for muscle agriculture, gait, balance, motor function, aerobic/anaerobic fitness, daily living, mobility, and school participation were categorised. RESULTS: The overall RoB of four randomised clinical trials was low, one had some concerns and two were rated as high. Moderate evidence was found that power exercises increased walking speed, activities of daily living, muscle strength, and enhanced gross motor function more than a routine physical therapy program. CONCLUSIONS: The lack of stronger evidence for power training interventions to improve muscle architecture, muscle function, walking capacity, and mobility in children with CP might be explained by the differences in training protocols and degree to which these meet the physiological definition of power, different methods of measuring power, limited durations of training, and the relative effectiveness of control interventions. Future studies should include a stronger focus on child and family-centred participation goals.Implications For RehabilitationPower training can improve gross motor function, walking speed, muscle strength, and activities of daily living more than routine physical therapy.Results comparing power training versus traditional strength training were less pronounced likely because both are intensive and may have positive effects.More research is needed to investigate effects of power training on participation.

Using Physiological Laboratory Tests and Neuromuscular Functions to Predict Extreme Ultratriathlon Performance.

Purpose: This study aims to investigate the relationship between split disciplines and overall extreme ultra-triathlon (EUT) performance and verify the relationship among physiological and neuromuscular measurements with both fractional and total EUT performance while checking which variables could predict partial and overall EUT race time. Methods: Eleven volunteers (37 ± 6 years; 176.9 ± 6.1 cm; 77.9 ± 10.9 kg) performed two maximal graded tests (cycling and running) for physiological measurements and muscle strength/power tests to assess neuromuscular functions. Results: The correlation of swimming split times to predict overall EUT race times was lower than for cycling and running split times (r2 = 0.005; p > .05; r2 = 0.949; p < .001 and r2 = 0.925; p < .001, respectively). VO2peak obtained during running test (VO2peakrun) and VT power output assessed during cycling test (VTPO) were the highest predictors of cycling performance (r2 = 0.92; p = .017), whereas VO2peakrun and peakpower output in the cycling test (PPO) were the highest predictors of running performance (r2 = 0.94; p = .008). Conclusion: VO2peakrun and VTPO, associated to jump height assessed during countermovement jump (CMJ) test were the highest correlated variables to predict total EUT performance (r2 = 0.99; p = .007). In practical terms, coaches should include the assessment of VO2peakrun, VTPO, and CMJ to evaluate the athletes' status and monitor their performance throughout the season. Future studies should test how the improvement of these variables would affect EUT performance during official races.

Mental Fatigue Effects on the Produced Perception of Effort and Its Impact on Subsequent Physical Performances.

The purpose of this study was to investigate the relationship between mental fatigue induced by a demanding cognitive task and impaired physical performance in endurance due to a higher perception of effort. A total of 12 healthy adults and volunteers, who had previously practiced endurance activities for 4 to 8 h per week, performed a one-hour cognitive task involving either the process of response inhibition (Stroop task) or not (visualization of a documentary as control task), then 20 min of pedaling on a cycle ergometer at a constant perception of effort while cardio-respiratory and neuromuscular functions were measured. The Stroop task induces subjective feelings of mental fatigue (vigor: 3.92 ± 2.61; subjective workload: 58.61 ± 14.57) compared to the control task (vigor: 5.67 ± 3.26; p = 0.04; subjective workload: 32.5 ± 10.1; p = 0.005). This fatigue did not act on the produced perceived effort, self-imposed, and did not affect the cardio-respiratory or neuromuscular functions during the subsequent physical task whose type was medium-term endurance. Regardless of the mental condition, the intensity of physical effort is better controlled when the participants in physical activity control their perception of effort. Mental fatigue does not affect subsequent physical performance but estimated perceived exertion, which increases with the intensity and duration of the exercise.

The Effect of Aquatic Plyometric Training on Jump Performance Including a Four-week Follow-up in Youth Female Volleyball Players.

This study aimed to analyze the effect of aquatic plyometric training (APT) on jump performance in volleyball players. Twelve female athletes (16.6 ± 0.9 years) were assessed through the following jump tests: spike height (SH), squat jump (SJ), countermovement jump (CMJ) and CMJ with an arm swing (CMJA). Jump height in each test and the eccentric utilization ratio (EUR) were the outcome measures. APT consisted of sets of drop jumps for 6 weeks (2 sessions/week) at a water depth of 0.75 m. Tests were performed at the beginning of a five-week pre-season period, before and after APT, and four weeks later for the follow-up. Repeated measures ANOVAs were used to analyze data and Hedges' g to estimate effect size (ES). Performance of all jumps did not change from baseline to Pre-APT. Performance improved in SH (p < 0.001, ES: 1.09), the SJ (p = 0.045, ES: 0.76) and the CMJA (p < 0.001, ES: 0.78) after APT when compared to Pre-APT. No changes were observed after the follow-up period. In conclusion, including six weeks of APT in the training routine of youth volleyball players improved performance of a sport-specific task (SH), the SJ and CMJA, with gains preserved after a four-week follow-up.

Effects of chains squat training with different chain load ratio on the explosive strength of young basketball players' lower limbs.

The purpose of this study was to explore the effects of the chain squat training (CST) with different chain load ratio (0, 10%, 20% and 30%) on the explosive power of the lower limbs of adolescent male basketball players. Forty-four youth basketball players (age 15.48 ± 0.81 years, body mass 78.86 ± 12.04 kg, height 184.95 ± 6.71 cm) were randomly allocated to one of the four groups: traditional squat training (TST), 10% chains squat training (10% CST), 20% chains squat training (20% CST), and 30% chains squat training (30% CST). Training interventions were performed 2 times per week for 6 weeks, and at the week before (Pre) and after (Post) the 6-week CST program with different chain load ratio, the no-step vertical jump, standing long jump, 15 m shuttle run, 1 R M squat and 30 m sprint test were performed. A 4 (group) × 2 (time) repeated measures analysis of variances (ANOVA) was calculated to show the scatter of each variable, and the Bonferroni's post-hoc test was used for multiple comparisons, in addition the partial eta-squared (η2) was calculated as an estimate of the ES. Significant time × group interaction was noticed for the no-step vertical jump (p < 0.001; η2 = 0.611), standing long jump (p < 0.001; η2 = 0.490) and 1 R M squat (p < 0.01; η2 = 0.333) indicating that better improvements appear in CST compared to TST. However, significant time × group interaction was noted for 15 m shuttle run (p < 0.001; η2 = 0.428), in favor of TST compared to CST. In addition, the improvements in 30 m sprint were similar between all groups. In conclusion, CST with more chain load has better training effects on lower limb explosive strength and maximum strength, based on the improvement in 1 R M squat and jumping performance. Besides, compared with TST, CST with more chain load might not help to develop better velocity adaptation at higher range of movement.

The Effects of High-Intensity Power Training versus Traditional Resistance Training on Exercise Performance.

Background: High-intensity interval training (HIIT) features short, repeated bursts of relatively vigorous exercise with intermittent periods of rest or low-intensity exercise. High-intensity power training (HIPT), in combination with HIIT and traditional resistance training (TRT), is characterized as multijoint high-intensity resistance exercises with low interset rest periods. HIPT requires people to finish the exercise as fast as possible, which increases acute physiological demands. The aim of the study was to investigate the differences between eight-week HIPT or TRT on exercise performance. Methods: Twenty-four college students were recruited and randomly assigned to either the HIPT or TRT group in a counterbalanced order. The power of upper and lower limbs (50% 1RM bench press and vertical jump) and anaerobic power were tested before and after the training (weeks 0 and 9). The results were analyzed by two-way analysis of variance (ANOVA) or Friedman's test with a significance level of α = 0.05 to compare the effects of the intervention on exercise performance. Results: There were significant differences in the explosive force of the upper and lower limbs between the pretest and post-test in both the HIPT and TRT groups (p < 0.05). However, only the HIPT group showed a significant difference in the mean power on the Wingate anaerobic test between the pretest and post-test (p < 0.05). Conclusions: Both HIPT and TRT can improve upper and lower limb explosive force. HIPT is an efficient training protocol, which took less time and produced a better improvement in mean anaerobic power.