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Non-local muscle fatigue effects on muscle strength, power, and endurance in healthy individuals
(2021)
Background
The fatigue of a muscle or muscle group can produce global responses to a variety of systems (i.e., cardiovascular, endocrine, and others). There are also reported strength and endurance impairments of non-exercised muscles following the fatigue of another muscle; however, the literature is inconsistent.
Objective
To examine whether non-local muscle fatigue (NLMF) occurs following the performance of a fatiguing bout of exercise of a different muscle(s).
Design
Systematic review and meta-analysis.
Search and Inclusion
A systematic literature search using a Boolean search strategy was conducted with PubMed, SPORTDiscus, Web of Science, and Google Scholar in April 2020, and was supplemented with additional 'snowballing' searches up to September 2020. To be included in our analysis, studies had to include at least one intentional performance measure (i.e., strength, endurance, or power), which if reduced could be considered evidence of muscle fatigue, and also had to include the implementation of a fatiguing protocol to a location (i.e., limb or limbs) that differed to those for which performance was measured. We excluded studies that measured only mechanistic variables such as electromyographic activity, or spinal/supraspinal excitability. After search and screening, 52 studies were eligible for inclusion including 57 groups of participants (median sample = 11) and a total of 303 participants.
Results
The main multilevel meta-analysis model including all effects sizes (278 across 50 clusters [median = 4, range = 1 to 18 effects per cluster) revealed a trivial point estimate with high precision for the interval estimate [- 0.02 (95% CIs = - 0.14 to 0.09)], yet with substantial heterogeneity (Q((277)) = 642.3, p < 0.01), I-2 = 67.4%). Subgroup and meta-regression analyses showed that NLMF effects were not moderated by study design (between vs. within-participant), homologous vs. heterologous effects, upper or lower body effects, participant training status, sex, age, the time of post-fatigue protocol measurement, or the severity of the fatigue protocol. However, there did appear to be an effect of type of outcome measure where both strength [0.11 (95% CIs = 0.01-0.21)] and power outcomes had trivial effects [- 0.01 (95% CIs = - 0.24 to 0.22)], whereas endurance outcomes showed moderate albeit imprecise effects [- 0.54 (95% CIs = - 0.95 to - 0.14)].
Conclusions
Overall, the findings do not support the existence of a general NLMF effect; however, when examining specific types of performance outcomes, there may be an effect specifically upon endurance-based outcomes (i.e., time to task failure). However, there are relatively fewer studies that have examined endurance effects or mechanisms explaining this possible effect, in addition to fewer studies including women or younger and older participants, and considering causal effects of prior training history through the use of longitudinal intervention study designs. Thus, it seems pertinent that future research on NLMF effects should be redirected towards these still relatively unexplored areas.
Introduction This study examined the effects of an 8-week backward running (BR) vs. forward running (FR) training programmes on measures of physical fitness in young female handball players.
Methods Twenty-nine players participated in this study. Participants were randomly assigned to a FR training group, BR training group, and a control group.
Results and discussion Within-group analysis indicated significant, small-to-large improvements in all performance tests (effect size [g] = 0.36 to 1.80), except 5-m forward sprint-time in the BR group and 5- and 10-m forward sprint-time in the FR group. However, the CG significantly decreased forward sprint performance over 10-m and 20-m (g = 0.28 to 0.50) with no changes in the other fitness parameters. No significant differences in the amount of change scores between the BR and FR groups were noted. Both training interventions have led to similar improvements in measures of muscle power, change of direction (CoD) speed, sprint speed either forward or backward, and repeated sprint ability (RSA) in young female handball players, though BR training may have a small advantage over FR training for 10-m forward sprint time and CoD speed, while FR training may provide small improvements over BR training for RSAbest. Practitioners are advised to consider either FR or BR training to improve various measures of physical fitness in young female handball players.
This study explored the effects of an 8-week repeated backward running training (RBRT) programme on measures of physical fitness in youth male soccer players. Youth male soccer players were randomly allocated into a RBRT group (n = 20; 13.95 +/- 0.22y) or a control group (CG; n = 16; 14.86 +/- 0.29y). The CG continued normal soccer training, while the RBRT group replaced some soccer drills with RBRT twice per week. Within-group analysis revealed that RBRT improved all performance variables ( increment -9.99% to 14.50%; effect size [ES] = -1.79 to 1.29; p <= 0.001). Meanwhile, trivial-to-moderate detrimental effects on sprinting and change of direction (CoD) speed ( increment 1.55% to 10.40%; p <= 0.05) were noted in the CG. The number of individuals improving performance above the smallest worthwhile change ranged from 65-100% across all performance variables in the RBRT group, whereas<50% in the CG reached that threshold. The between-group analysis indicated that the RBRT group improved performance on all performance tasks more than the CG (ES = -2.23 to 1.10; p <= 0.05). These findings demonstrate that substituting part of a standard soccer training regimen with RBRT can enhance youth soccer players' sprinting, CoD, jumping, and RSA performance.
Push-ups represent one of the simplest and most popular strengthening exercise. The aim of this study was to systematically review and critically appraise the literature on the kinetics-related characteristics of different types of push-ups, with the objective of optimising training prescription and exercise-related load. A systematic search was conducted in the electronic databases PubMed, Google Scholar and Science Direct up to April 2018. Studies that reported kinetic data (e.g. initial and peak-force supported by the upper-limbs, impact-force, peak-flexion-moment of the elbow-joint, rate of propulsive- and impact-, and vertebral-joint compressive-forces) related to push-ups and included trained, recreational and untrained participants, were considered. The risk of bias in the included studies was assessed using the Critical Appraisal Skills Programme scale. From 5290 articles retrieved in the initial search, only 26 studies were included in this review. Kinetic data for 46 push-up variants were assessed. A limitation of the current review is that the relationship between our findings and actual clinical or practical consequences is not statistically proven but can only be inferred from our critical descriptive approach. Overall, this review provides detailed data on specific characteristics and intensities of push-up variations, in order to optimise exercise prescription for training and rehabilitation purposes.
Introduction General and particularly sport-specific testing is an integral aspect of performance optimization in artistic gymnastics. In artistic gymnastics, however, only non-specific field tests have been used to assess endurance performance (e.g., Multistage Shuttle Run Test; Cooper's Test).
Methods This study aimed to examine the validity of a new sport-specific endurance test in artistic gymnastics. Fourteen elite-level gymnasts (i.e., eight males and six females) participated in this study. The newly developed artistic gymnastics-specific endurance test (AGSET) was conducted on two different occasions seven days apart to determine its reliability. To assess the concurrent validity of AGSET, participants performed the multistage shuttle run test (MSRT). Maximum oxygen uptake (VO2max) and respiratory exchange ratio (RER) were directly assessed using a portable gas analyzer system during both protocols. Additionally, the total time maintained (TTM) during the AGSET, maximum heart rate (HRmax), maximal aerobic speed (MAS), and blood lactate concentration (BLa) during the two protocols were collected.
Results The main findings indicated that all variables derived from the AGSET (i.e., VO2max, MAS, HRmax, BLa, and RER) displayed very good relative (all intraclass correlation coefficients [ICC] > 0.90) and absolute (all typical errors of measurement [TEM] < 5%) reliability. Further, results showed that the ability of the AGSET to detect small changes in VO2max, MAS, BLa, and RER was good (smallest worthwhile change [SWC0.2] > TEM), except HRmax (SWC0.2 < TEM). Additionally, results showed a nearly perfect association between the VO2max values derived from the AGSET and MSRT (r = 0.985; coefficient of determination [R-2] = 97%) with no statistically significant differences (p>0.05). The mean (bias) +/- 95% limits of agreement between the two protocols were 0.28 +/- 0.55 mlminkg-1.
Discussion AGSET seems to present very good reliability and concurrent validity for assessing endurance performance in elite artistic gymnastics. In addition, the newly developed protocol presents a good ability to detect small changes in performance.
Objective:
This study aimed to systematically review and meta-analyze the effect of flywheel resistance training (FRT) versus traditional resistance training (TRT) on change of direction (CoD) performance in male athletes.
Methods:
Five databases were screened up to December 2021.
Results:
Seven studies were included. The results indicated a significantly larger effect of FRT compared with TRT (standardized mean difference [SMD] = 0.64). A within-group comparison indicated a significant large effect of FRT on CoD performance (SMD = 1.63). For TRT, a significant moderate effect was observed (SMD = 0.62). FRT of <= 2 sessions/week resulted in a significant large effect (SMD = 1.33), whereas no significant effect was noted for >2 sessions/week. Additionally, a significant large effect of <= 12 FRT sessions (SMD = 1.83) was observed, with no effect of >12 sessions. Regarding TRT, no significant effects of any of the training factors were detected (p > 0.05).
Conclusions:
FRT appears to be more effective than TRT in improving CoD performance in male athletes. Independently computed single training factor analyses for FRT indicated that <= 2 sessions/week resulted in a larger effect on CoD performance than >2 sessions/week. Additionally, a total of <= 12 FRT sessions induced a larger effect than >12 training sessions. Practitioners in sports, in which accelerative and decelerative actions occur in quick succession to change direction, should regularly implement FRT.
Biological maturation has been shown to affect male youths' responses to plyometric training (PT). However, to date, no researcher has examined the effect of maturation on the effects of PT in female youth. We undertook the first controlled intervention study to examine this, focusing on adaptive responses to countermovement jump (CMJ), reactive strength index (RSI), and change of direction (COD) performance in groups of female youth divided by maturation status (years from peak height velocity [PHV]). The training program lasted 7 weeks with subjects undertaking 2 sessions of PT per week. In the mid-PHV group, there was a small increase (effect size; 90% confidence interval = 0.40; -0.23 to 1.03) in CMJ performance. No changes were observed in the post-PHV group (0.02; -0.68 to 0.72). For RSI, there was a moderate increase in the mid-PHV group (0.94; 0.29-1.59) with only a trivial increase in the post-PHV group (0.06; -0.65 to 0.76). The intervention exerted no positive effect on COD performance in any group. Plyometric training seems to enhance CMJ and RSI in female youth, although the magnitude of adaptation could be affected by maturation status. A twice-per-week program of multidirectional jumping and hopping, with bilateral and unilateral components, can be used as a preparatory precursor to physical education classes or recreational sport.
This study examined the effect of 6 weeks of progressed and nonprogressed volume-based overload plyometric training (PT) on components of physical fitness and body composition measures in young male basketball players, compared with an active control group. Subjects were randomly assigned to a progressed PT (PPT, n = 7; age = 14.6 +/- 1.1 years), a non-PPT (NPPT, n = 8, age = 13.8 +/- 2.0 years), or a control group (CG, n = 7, age = 14.0 +/- 2.0 years). Before and after training, body composition measures (muscle mass and fat mass), countermovement jump with arms (CMJA) and countermovement jump without arms (CMJ), horizontal bilateral (HCMJ) and unilateral jump with right leg (RJ) and left leg (LJ), 20-cm drop jump (DJ20), sprint speed (10 m sprint), and change of direction speed (CODS [i.e., T-test]) were tested. Significant effects of time were observed for muscle and fat mass, all jump measures, and CODS (all p < 0.01; d = 0.37-0.83). Significant training group x time interactions were observed for all jump measures (all p < 0.05; d = 0.24-0.41). Post hoc analyses revealed significant pre-post performance improvements for the PPT (RJ and LJ: increment 18.6%, d = 0.8 and increment 22.7%, d = 0.9, respectively; HCMJ: increment 16.4%, d = 0.8; CMJ: increment 22.4%, d = 0.7; CMJA: increment 23.3%, d = 0.7; and DJ20: increment 39.7%, d = 1.1) and for the NPPT group (LJ: increment 14.1%, d = 0.4; DJ20: increment 32.9%, d = 0.8) with greater changes after PPT compared with NPPT for all jump measures (all p < 0.05; d = 0.21-0.81). The training efficiency was greater (p < 0.05; d = 0.22) after PPT (0.015% per jump) compared with NPPT (0.0053% per-jump). The PPT induced larger performance improvements on measures of physical fitness as compared to NPPT. Therefore, in-season progressive volume-based overload PT in young male basketball players is recommended.
We are glad to introduce the Second Journal Club of Volume Five, Second Issue. This edition is focused on relevant studies published in the last few years in the field of resistance training, chosen by our Editorial Board members and their colleagues. We hope to stimulate your curiosity in this field and to share with you the passion for the sport, seen also from the scientific point of view. The Editorial Board members wish you an inspiring lecture.
We are glad to introduce the Second Journal Club of Volume Five, Second Issue. This edition is focused on relevant studies published in the last few years in the field of resistance training, chosen by our Editorial Board members and their colleagues. We hope to stimulate your curiosity in this field and to share with you the passion for the sport, seen also from the scientific point of view. The Editorial Board members wish you an inspiring lecture.