Promoting lower extremity strength in elite volleyball players: Effects of two combined training methods

ObjectivesTo compare the impact of short term training with resistance plus plyometric training (RT+P) or electromyostimulation plus plyometric training (EMS+P) on explosive force production in elite volleyball players.DesignSixteen elite volleyball players of the first German division participated in a training study.MethodsThe participants were randomly assigned to either the RT+P training group (n = 8) or the EMS+P training group (n = 8). Both groups participated in a 5-week lower extremity exercise program. Pre and post tests included squat jumps (SJ), countermovement jumps (CMJ), and drop jumps (DJ) on a force plate. The three-step reach height (RH) was assessed using a custom-made vertec apparatus. Fifteen m straight and lateral sprint (S15s and S15l) were assessed using photoelectric cells with interims at 5 m and 10 m.ResultsRT+P training resulted in significant improvements in SJ (+2.3%) and RH (+0.4%) performance. The EMS+P training group showed significant increases in performance of CMJ (+3.8%), DJ (+6.4%), RH (+1.6%), S15l (?3.8%) and after 5 m and 10 m of the S15s (?2.6%; ?0.5%). The comparison of training-induced changes between the two intervention groups revealed significant differences for the SJ (p = 0.023) in favor of RT+P and for the S15s after 5 m (p = 0.006) in favor of EMS+P.ConclusionsThe results indicate that RT+P training is effective in promoting jump performances and EMS+P training increases jump, speed and agility performances of elite volleyball players.     

Isokinetic resistance training combined with eccentric overload improves athletic performance and induces muscle hypertrophy in young ice hockey players

ObjectivesTo determine the combined effects of slow isokinetic resistance training and eccentric overload and compare it to traditional resistance training on strength, power, body composition and muscle hypertrophy in young ice hockey players.DesignExperimental, randomized trial.MethodsTwenty-two resistance-trained ice hockey players (18 ± 1 year) were assigned to either isokinetic resistance training and eccentric overload (ISO/ECC; n = 11) or traditional resistance training (TRAD; n = 11). Participants underwent supervised progressive resistance training for 8 weeks (2–3 sessions/week) involving lower body multiple-joint exercises (heavy squats and explosive jump squats). The ISO/ECC group performed their training using a computerized robotic engine system (1080 Quantum synchro, Sweden), whereas the TRAD group performed the same resistance exercises with isotonic loading. Before and after the intervention, participants were evaluated in 1RM back squat, loaded jump squats, sprint- and jump performance, body composition and muscle thickness using ultrasound measurement.ResultsSimilar moderate increases in 1RM back squat and power output in the jump squats were found in both the ISO/ECC and TRAD groups (11–17%, P < 0.01), whereas only the ISO/ECC group showed improvements in drop jump performance (9.8%, P = 0.01). Moreover, similar trivial changes in body composition were observed in both groups, while only the ISO/ECC training group increased muscle thickness in the vastus intermedius (P = 0.01) and rectus femoris muscles (P = 0.03).ConclusionsBoth modalities effectively increased maximal strength and power output, whereas isokinetic resistance training, combined with eccentric overload, improved drop jump performance and induced greater muscle hypertrophy than traditional training in young ice hockey players.     

Back squat velocity to assess neuromuscular status of rugby league players following a match

ObjectivesBack squat mean concentric velocity (MV) and countermovement jump (CMJ) performance were examined in sub-elite rugby league players post-match to monitor changes in neuromuscular status (NMS) from baseline. Relationships between changes in back squat MV and CMJ performance variables were used to compare back squat MV to an established method to monitor NMS.DesignLongitudinal observational design.Methods18 male sub-elite rugby league players (mean ± SD, 20.5 ± 2.4 yr; 180.0 ± 6.7 cm; 93.3 ± 11.2 kg) performed 3 repetitions of CMJ and back squat with an individualised, pre-determined load at ?2 h (baseline), +30 min, +24 h, and +48 h in relation to a match. Back squat MV, CMJ height, CMJ peak power, and CMJ peak velocity were measured with a linear position transducer.ResultsSignificant (p < 0.05), small to large decreases (ES = 0.52–1.24) were observed in back squat MV up to +48 h post-match. Significant (p < 0.05), small to moderate decreases (ES = 0.52–0.70) in CMJ height were also observed up to +24 h post-match, returning to baseline at +48 h. CMJ peak power and peak velocity post-match changes were not significant compared to baseline (p > 0.05). Significant positive correlations were found between changes in back squat MV and CMJ height at +30 min (r = 0.59; p = 0.009) and +48 h (r = 0.51; p = 0.03).ConclusionsThese findings suggest back squat MV may be a suitable alternative or addition to CMJ testing for monitoring NMS in rugby league players.     

Identifying risk factors for contact injury in professional rugby league players – Application of a frailty model for recurrent injury

ObjectivesWell-developed physical qualities may protect against contact injuries. However, the potential contribution of physical qualities as risk or protective factors to contact injury risk is yet to be determined for rugby league. This study applied a frailty survival model that accounts for recurrent injury to identify risk factors for all physiotherapist-reported contact injury in professional rugby league players.DesignProspective cohort study.MethodsSixty-six professional rugby league players participated in this three successive year prospective study. At the start of each season, all players underwent measurements of standard anthropometry (height, body mass, and sum of seven skinfolds), speed (10 m and 40 m sprint), muscular strength (1 repetition maximum [RM] bench press, 1RM squat, 1RM weighted chin-ups), power (vertical jump, bench throw, 1RM power clean, jump squat), and endurance (maximum repetition bench press with 60 kg resistance), repeated-sprint ability (12 × 20 m sprints performed on a 20 s cycle), prolonged high-intensity intermittent running ability (8 × 12 s maximal effort shuttles performed on a 48 s cycle), and maximal aerobic power (multi-stage fitness test). Data was used to demonstrate the application of the frailty model extension of the Cox proportional regression model for recurrent events to identify factors associated with a high hazard ratio (HR) of injury.ResultsHeavier (body mass, HR = 2.6, 95% CI = 1.2–5.7), and faster (40 m sprint, HR = 2.1, 95% CI = 1.0–4.2) players, and those with poorly developed prolonged high-intensity intermittent running ability (HR = 2.9, 95% CI = 1.7–5.0) and upper-body strength (chin-up, HR = 2.2, 95% CI = 1.3–3.7) had a higher incidence of contact injuries.ConclusionsThis study demonstrates application of a novel statistical approach for the analysis of injury data that is recurrent in nature. This approach identified that the greater impact forces generated from heavier players with faster speed may result in an increase in recurrent contact injury rates. However, the development of prolonged high-intensity intermittent running ability and upper-body strength and power may assist to reduce the risk of contact injury in professional rugby league players.     

Resistance training to improve power and sports performance in adolescent athletes: A systematic review and meta-analysis

ObjectivesResistance training in untrained adolescents can positively effect health-related fitness as well as improve muscular power and sports performance. The impact of resistance training on adolescent athletes is less clear. The purpose of this review is to determine the effectiveness of resistance training programs on muscular power and sports performance in adolescent athletes.DesignSystematic review and meta-analysis of previously published studies investigating resistance training in adolescent athlete populations.MethodsA systematic search of Medline, Embase, and SPORTDiscus databases was conducted on 21st March 2011 to identify studies evaluating resistance training programs on power and sports performance in adolescent athletes.ResultsThirty-four studies were identified. All but two of the studies reported at least one statistically significant improvement in an alactic muscular power outcome. The most common indicators of alactic power were vertical jump (25 studies) and sprint running (13 studies) performance. Fourteen studies provided data to allow for pooling of results in a meta-analysis. A positive effect was detected for resistance training programs on vertical jump performance (mean difference 3.08 [95% CI 1.65, 4.51], Z = 4.23 [P < 0.0001]).ConclusionsThere is sufficient evidence to conclude that resistance-training interventions can improve muscular power in adolescent athletes. A positive effect on sports performance attributable to participation in resistance training was reported by almost half the included studies, however limited objective evidence to support these claims was found. Improvements in motor performance skills, such as jumping, are widely stated as indicators of improvements in sporting performance.     

Diagnostic of footwork characteristics and running speed demands in tennis on different ground surfaces

BackgroundAnalysis of court surface effects on foot work and running speed and analysis of correlation between general speed and jump performance and the complex running performance in tennis.Materials and Methods12 male tennis players performed a tennis specific baseline shuttle run test including one change of direction (SR), either on clay or on an indoor carpet court. Additionally, subjects completed a linear sprint test, a counter movement jump (CMJ), and a drop jump (DJ).ResultsSR running time (clay: 3.63 ± 0.08 s; carpet: 3.31 ± 0.15 s), change direction time (clay: 1.24 ± 0.09; carpet: 1.09 ± 0.04 s) and ground contact time during the last step while changing direction (clay: 0.92 ± 0.13; carpet: 0.47 ± 0.13 s) were significantly longer on clay (P < 0.05). Linear sprint and jump tests showed no or only weak correlations with SR on both surfaces.ConclusionFoot work and running speed demands in tennis are different depending on the court surface and require specific training interventions and testing procedures.     

The effects of the Nordic hamstring exercise on sprint performance and eccentric knee flexor strength: A systematic review and meta-analysis of intervention studies among team sport players

ObjectivesThe primary aim of this study was to investigate the effects of the Nordic hamstring exercise (NH_E) on sprint performance (i.e., 5, 10 and 20 m) and explore associations between study characteristics and sprint outcomes in team sport players. Secondary aims were to (1) investigate the effects of the NH_E on eccentric strength of the knee flexors (ES_KF) with categorical subgroup analysis to determine differences between recreationally, well-trained individuals and young athletes, (2) determine the relation between ES_KF and sprint performance in team sport players, and (3) explore the effect of study characteristics (i.e., weekly volume, time duration and body mass) on ES_KF.MethodsElectronic databases were searched until the 20th of June 2020. 17 studies met the inclusion criteria. Random-effects meta-analyses were used to determine the mean difference (MD) or standardized change of mean difference (SCMD) between NH_E and control group for sprint time and ES_KF, respectively.ResultsNH_E interventions showed a positive effect on sprint performance (−0.04 s [−0.08, −0.01]). Sub-group meta-analyses indicated no significant differences in 5 and 20 m sprint performance (MD_sprint(5m) = −0.02 s [−0.10, 0.06]) and (MD _sprint(20m) = −0.05 s [−0.30, 0.19]), respectively. A significant difference was however found for 10 m sprint performance (MD_sprint(10m) = −0.06 s [−0.10, −0.01]). Meta-analysis on the effects of the NH_E on ES_KF showed a significant benefit of 0.83 SCMD [0.55, 1.12] in favour of the intervention group.ConclusionsStudies with some concerns or high risk of bias show that training programs involving the NH_E can have small beneficial effects on sprint performance in team sport players. Studies with some concerns or high risk of bias showed moderate beneficial effects on ES_KF among a sample of relatively untrained individuals. However, for well-trained team sport players, the improvements in ES_KF were less consistent, suggesting a higher training intensity during the NH_E may be required to induce adaptations.     

Comprehensive physical fitness and high blood pressure in children and adolescents: A national cross-sectional survey in China

ObjectivesTo assess the association between comprehensive physical fitness and high blood pressure (HBP) among Chinese children and adolescents.DesignNational cross-sectional surveys.Methods214,301 school students’ data aged 7−18 years was extracted in 2014. Six components of physical fitness (forced vital capacity, standing long jump, sit-and-reach, body muscle strength, 50 m dash and endurance running) were measured, standardized and aggregated as a summary physical fitness indicator (PFI). HBP, systolic HBP (SHBP) and diastolic HBP (DHBP) were defined according to sex-, age- and height-specific references in China.ResultsThe prevalence of HBP, SHBP and DHBP was 8.6%, 4.7% and 5.7%, respectively, and PFI was −0.9 in Chinese children and adolescents. A significant negative association between the PFI and HBP was observed with adjusted prevalence of HBP (10.8% (95% CI: 10.4–11.2) to 7.6% (95% CI: 7.3–8.0), P_trend < 0.001), SHBP (5.7% (95% CI: 5.4–6.1) to 4.4% (95% CI: 4.1–4.6), P_trend < 0.001), and DHBP (7.6% (95% CI: 7.2–7.9) to 4.6% (95% CI: 4.3–4.9), P_trend < 0.001) and their ORs (HBP: 0.87(95% CI: 0.82–0.93) to 0.68(95% CI: 0.64–0.73), P_trend < 0.001; SHBP: 0.86(95% CI: 0.79–0.94) to 0.75(95% CI:0.69–0.82), P_trend < 0.001; DHBP: 0.85(95% CI: 0.79–0.92) to 0.59(95% CI: 0.54–0.64), P_trend < 0.001) declined with the increase in PFI. Stratified nutritional status exhibited a similar negative association between PFI and HBP, SHBP and DHBP in children with normal weight, overnutrition, and undernutrition. Stand long jump, body muscle strength, 50 m dash, and endurance running, had a negative association with HBP, SHBP and DHBP, but forced vital capacity had a positive such association. Sit-and-reach and HBP are not significantly associated.ConclusionsPhysical fitness was negatively correlated to the increased HBP in children and adolescents. Comprehensive policies and measures to enhance children and adolescents’ physical fitness are urgently needed through the promotion of physical activity, healthy dietary patterns, and strategies of educational guidelines to reduce schoolwork, which will in turn reduce the cardiovascular burdens in the future.     

Considerations in interpreting neuromuscular state in elite level Australian Rules football players

ObjectivesExamine the influence of test modality, season stage, match load and physical qualities on the interpretation of neuromuscular function (NF) post Australian Rules Football (ARF) matches.DesignRepeated measures design.MethodsThirty-two elite ARF players’ NF was assessed 72 h following competitive matches (7 ± 2) via the counter movement jump (CMJ) and isometric mid-thigh pull (IMTP). Influence of season stage, external load parameters (GPS; 10 Hz) and moderating influences of lower body strength (LBS), lower body power (LBP) and intermittent exercise capacity upon NF recovery were assessed using linear mixed effects models.ResultsModerate negative seasonal trends were evident for both rate of force development (RFD) 0?100 ms (d = ?0.86, 95%, CI: ±0.57) and 0?200 ms (d = ?0.76, CI: ±0.64). Significant but trivial effects of match load were observed between one standardised unit increase in high speed running (HSR) versus CMJ: Force at zero velocity (d = 0.12, CI: ±0.12), and sum of high intensity accelerations and CMJ: Eccentric deceleration RFD (d = ?0.18, CI: ±0.14). Accounting for baseline LBS better explained (weight of evidence: W = 87%) seasonal trends observed in IMTP: peak force, with lower LBS showing greater capacity for improvement. Positive moderating influences were observed with baseline LBS and LBP (W = 91 & 75%) on CMJ: eccentric mean power responses to HSR, and CMJ: jump height responses to very-HSR, respectively.ConclusionsInterpretation of athlete NF responses is complicated by the inconsistent and interacting influence of contextual factors (assessment modality, stage of season, load), in-particular higher baseline LBS and LBP may improve acute load related responses of NF.     

Exercise-based injury prevention for community-level adolescent cricket pace bowlers: A cluster-randomised controlled trial

ObjectivesTo investigate if an exercise-based injury prevention program (IPP) can modify risk factors for injury in community-level adolescent cricket pace bowlers.DesignCluster-randomised controlled trial.MethodsEight cricket organisations (training two times per week and no previous involvement in a structured IPP) participated in this cluster-randomised trial. Participants were aged 14–17 years, injury free, and not currently performing a rehabilitation/exercise program. Cricket organisations (clusters) were block-randomised by computerised number generation into an intervention group (performed an eight-week IPP at training) or control group (continued their usual cricket activity). Participants were not blinded to group allocation. Strength, endurance, and neuromuscular control were assessed at baseline and follow-up. Treatment effects were estimated using linear mixed models.ResultsSixty-five male adolescent pace bowlers (intervention n = 32 and control n = 33) were randomised. There were significant treatment effects favouring the intervention group for shoulder strength (90°/s) 0.05 (95% CI 0.02–0.09) N m/kg, hamstring strength (60°/s) 0.32 (95% CI 0.13–0.50) N m/kg, hip adductor strength dominant 0.40 (95% CI 0.26–0.55) N m/kg and non-dominant 0.33 (95% CI 0.20–0.47) N m/kg, SEBT reach distance dominant 3.80 (95% CI 1.63–6.04) percent of leg length (%LL) and non-dominant 3.60 (95% CI 1.43–5.78) %LL, and back endurance 20.4 (95% CI 4.80–36.0) seconds. No differences were observed for shoulder strength (180°/s) (p = 0.09), hamstring strength (180°/s) (p = 0.07), lumbopelvic stability (p = 0.90), and single leg squat knee valgus angle (dominant p = 0.06, non-dominant p = 0.15).ConclusionsExercise-based IPPs can modify risk factors for injury in community-level adolescent pace bowlers. Future research is needed to confirm if IPPs can also reduce injury risk in this population.     

The effect of training order on neuromuscular,endocrine and mood response to small-sided games and resistance training sessions over a 24-h period

ObjectivesThis study examined the acute effect of small-sided-game (SSG) and resistance training sequence on neuromuscular, endocrine and mood response over a 24-h (h) period.DesignRepeated measures.MethodsFourteen semi-professional soccer players performed SSG-training (4vs4 + goalkeepers; 6 × 7-min, 2-min inter-set recovery) followed by resistance training 2 h later (back-squat, Romanian deadlift, barbell-hip-thrust; 4 × 4 repetitions, 4-min inter-set recovery; 85% 1 rep-max) (SSG + RES), and on a separate week reversed the session order (RES + SSG). Physical demands of SSG’s were monitored using global positioning systems (GPS) and ratings of perceived exertion (RPE). Countermovement-jump (CMJ; peak power output; jump height) and brief assessment of mood were collected before (pre), during (0 h) and after (+24 h) both protocols. Salivary testosterone and cortisol concentrations were obtained at the same time-points but with the inclusion of a measure immediately prior to the second training session (+2 h).ResultsGPS outputs and RPE were similar between SSG-training during both protocols. Between-protocol comparisons revealed no significant differences at +24 h in CMJ performance, mood, and endocrine markers. Testosterone was higher at 0 h during RES + SSG in comparison to SSG + RES (moderate-effect; +21.4 ± 26.7 pg ml⁻¹; p = 0.010), yet was similar between protocols by +2 h.ConclusionsThe order of SSG and resistance training does not appear to influence the physical demands of SSG’s with sufficient recovery between two sessions performed on the same day. Session order did not influence neuromuscular, endocrine or mood responses at +24 h, however a favourable testosterone response from the resistance first session may enhance neuromuscular performance in the second session of the day.     

Changes in performance markers and wellbeing in elite senior professional rugby union players during a pre-season period: Analysis of the differences across training phases

ObjectivesTo assess the magnitude of change and association with variation in training load of two performance markers and wellbeing, over three pre-season training blocks, in elite rugby union athletes.DesignObservational.MethodsTwenty-two professional players (age 25 ± 5 years; training age 6 ± 5 years; body mass, 99 ± 13 kg; stature 186 ± 6 cm) participated in this study, with changes in lower (CMJ height) and upper body (bench press mean speed) neuromuscular function and self-reported wellbeing (WB) assessed during an 11-week period.ResultsThere was a small increase in CMJ height (0.27, ±0.17 – likely substantial; standardised effect size, ±95% confidence limits – magnitude-based inference) (p = 0.003), bench press speed (0.26, ±0.15 – likely substantial) (p = 0.001) and WB (0.26, ±0.12 – possibly substantial) (p < 0.0001) across the pre-season period. There was a substantial interaction in the effect of training load on these three variables across the three training phases. A two-standard deviation (2SD) change in training load was associated with: a small decrease in CMJ height during the power phase (−0.32, ±0.19 – likely substantial) (p = 0.001); a small reduction in bench press speed during the hypertrophy phase (−0.40, ±0.32 – likely substantial) (p = 0.02); and a small reduction in WB during the strength phase (−0.40, ±0.24 – very likely substantial) (p < 0.0001). The effects of changes in training load across other phases were either likely trivial, only possibly substantial, or unclear.ConclusionsThe effect of training load on performance can vary both according to the type of training stimulus being administered and based on whether upper- or lower-body outcomes are being measured.     

Factors influencing performance of competitive and amateur rhythmic gymnastics—Gender differences

During last decade, male athletes were involved in official rhythmic gymnastics (RG) competitions. Aim of this study was to examine anthropometric characteristics and motor skills of male rhythmic gymnasts to identify guidelines in talent identification, selection and development training plans. Twenty-four gymnasts (age range 22 ± 4 years), 12 male athletes and 12 female athletes, underwent two testing sessions: the previous session to assess anthropometric measures, and the second one to evaluate jumping ability using Optojump. Three vertical jumps: squat jump (SJ), counter-movement jump (CMJ), hopping test (HT) and three different technical jumps (Split Leap with stretched legs (SL); Cossack with 180° of rotation (CK); Jeté with turn (JWT)) were evaluated. Male gymnasts had significant higher values in each anthropometric measure than females (p < 0.01) except for sitting height/stature ratio, sitting height and fat mass (no significant differences). Female athletes were selected for their lowest fat mass. Height and ground contact time of technical leaps, squat jump and counter-movement jump, were significantly higher in male athletes than females. Height of hopping test (evaluating stiffness), and of difference between CMJ and squat jump (evaluating elastic properties of muscles) were no different between genders. Ground contact time of hopping test was significantly correlated (p < 0.05) with ground contact time of technical leaps. Results of the present study suggest that similar anthropometric characteristics have to be researched for both gymnasts’ gender. Reactivity and elastic muscle properties of the legs have to be research both in male and female athletes.     

Accelerometer detected lateral sway during a submaximal running test correlates with endurance exercise performance in elite Australian male cricket players

ObjectiveTo identify whether movement patterns during a standardized submaximal running test (SSRT), assessed by accelerometry, were associated with improvements in endurance exercise performance.DesignA retrospective analysis of data collected from the 2018–2019 Australian cricket preseason.MethodsThirty-nine high-performance male cricket players were studied (25 ± 3 years, 82 ± 6 kg, 183 ± 6 cm). SSRT was performed monthly prior to a two kilometre (km) running time trial (2 kmTT). SSRT involved running between markers, positioned twenty metres apart, for three minutes. Foot strikes were timed to a metronome (154 beats/min) to elicit a running speed of ˜eight km/h. Triaxial accelerometers were worn in vests on the upper back and used to assess PlayerLoad medio-lateral vector (PL1D_side%), vertical vector (PL1D_up%) and anterior-posterior vector (PL1D_fwd%) were assessed.Results2 kmTT performance improved over the study period (p < 0.05). PlayerLoad vectors during the first minute of SSRT were not related to 2 kmTT performance (p > 0.23). During the second and third minutes there were positive associations between 2 kmTT (run time) and PL1D_side% (SSRT_2min, β 2.12, p < 0.03, 95% CI: 0.22–4.01; SSRT3_min, β 2.30, p < 0.03, 95% CI:0.32–4.29), but not PL1D_up% (SSRT_2min, β −0.15, p = 0.77, 95% CI: −1.13–0.83; SSRT_3min, β −0.15, p = 0.77, 95% CI: −1.11–0.87) or PL1D_fwd% (SSRT_2min, β −0.45, p = 0.42, 95% CI: −1.49–0.62; SSRT_3min, B−0.45, p = 0.40, 95% CI: −1.51–0.60).ConclusionAssessment of PL1D_side% during the second or third minutes of SSRT may inform how an athlete’s endurance exercise performance is responding to changes in training load.     

Predictive modelling of the physical demands during training and competition in professional soccer players

ObjectivesThe present study aimed to predict the cut-off point-values that best differentiate the physical demands of training and competition tasks including friendly matches (FM), small sided games (SSG), large sided games (LSG), mini-goal games (MG) and ball circuit-training (CT) in professional soccer players.DesignExperimental randomized controlled trial.MethodsFourteen professional players participated in all tasks with the CT, SSG and MG consisting of 8 repetitions of 4-min game play, interspersed by 2-min of active recovery. The training data were compared to the first 32-min of the LSG and two competitive FM per player. All movement patterns from walking to sprint running were recorded using 10 Hz GPS devices while player perception of exertion was recorded via a visual analogue scale, post-task. Decision tree induction was applied to the dataset to assess the cut-off point-values from four training drills (SSG, LSG, MG, and CT) and FM for every parameter combination.ResultsDistance covered during jogging (2.3–3.3 m/s; >436 m), number of decelerations (≤730.5) and accelerations (≤663), and maximum velocity reached (>5.48 m/s) characterized the physical demands during competition (FM) with great variability amongst training drills.ConclusionThe use of these novel, cut-off points may aid coaches in the design and use of training drills to accurately prepare athletes for soccer competition.     

The effects of menthol on exercise performance and thermal sensation: A meta-analysis

ObjectivesMenthol is an organic compound with non-thermal cooling properties that has been shown to relieve thermal strain associated with exercise in the heat; however, its effects on performance have not been systematically analysed. The aims were to determine the effects of menthol applied (1) internally and (2) externally on exercise performance and thermal sensation.DesignMeta-analysisMethodsA search was performed using various databases in August 2018. The studies were screened using search criteria for eligibility. Thirteen peer-reviewed articles were identified for inclusion in a primary analysis on the effect of menthol on exercise performance; subsequently eleven of these articles were included in a secondary analysis on the effect of menthol on thermal sensation during exercise. A sub-analysis examining the application method was also performed.ResultsMenthol improved overall exercise performance (Hedges’ g = 0.33, 95% CI −0.00, 0.65 P = 0.05), demonstrating greater effects when applied internally (Hedges’ g = 0.40, 95% CI 0.04, 0.76, P = 0.03). Thermal sensation was also lowered overall across all studies (Hedges’ g = −0.54, 95% CI −0.67, −0.42, P < 0.001).ConclusionsExercise performance can be improved by application of non-thermally cooling menthol, which also reduces perceptual measures of thermal sensation. Internal application appears to be the best strategy to improve performance.     

Effect of concentric and eccentric hamstring training on sprint recovery,strength and muscle architecture in inexperienced athletes

ObjectivesTo investigate whether five-weeks of concentric (CON) or eccentric (ECC) hamstring strength training have different effects on recovery from sprint running, eccentric strength and architecture of the biceps femoris long head (BF_LH).DesignCohort study.MethodsThirty males (age, 22.8 ± 4.1 y; height, 180.1 ± 6.4 cm; weight, 85.2 ± 14.6 kg) were allocated into either a CON or ECC group, both performing nine sessions of resistance training. Prior to and immediately after the five-week intervention, each participant’s BF_LH fascicle length (FL), pennation angle (PA), muscle thickness (MT), peak isometric KF torque and Nordic eccentric strength were assessed. Post-intervention, participants performed two timed sprint sessions (10 × 80 m) 48 h apart. Blood samples and passive KF torques were collected before, immediately after, 24 h and 48 h after the first sprint session.ResultsAfter five-weeks of strength-training, fascicles lengthened in the ECC (p < 0.001; d = 2.0) and shortened in the CON group (p < 0.001; d = 0.92), while PA decreased for the ECC (p = 0.001; d = 0.52) and increased in the CON group (p < 0.001; d = 1.69). Nordic eccentric strength improved in both ECC (p < 0.001; d = 1.49) and CON (p < 0.001; d = 0.95) groups. No between-group differences were observed in peak isometric strength (p = 0.480), passive KF torques (p = 0.807), sprint performance decrements between sprint sessions (p = 0.317) and creatine kinase (p = 0.818).ConclusionsDespite inducing significant differences in BF_LH muscle architecture, there were no significant between group differences in sprint performance decrements across two sprint sessions.     

Resistance training in older women: effect on vertical jump and functional performance

AIM: Few studies have determined the effects of a heavy resistance training on vertical jump performance in older adults. The purpose of the present study was to evaluate the effects of a 12 week heavy resistance training in vertical jump and functional performance in healthy, inactive, older women. METHODS: Seventeen sedentary older women (aged 53-69 years) were assigned either to a control (C, n=8), or to a heavy resistance training (RT, n=9). The RT group trained knee extensors and flexors at 80% of 1-repetition maximum (1-RM), 3 days per week for 12 weeks. Both groups were evaluated in 1-RM lower body strength, squat jump (SJ) and countermovement jump (CMJ) height, and chair rising time, before and after the training period. RESULTS: After the training period, RT significantly improved (P<0.001) the 1-RM lower body strength, SJ, CMJ height, and chair rising by 68.9%, 24.5%, 21.7%, and 13%, respectively. Significant correlations were observed among the percent (%) change in 1-RM lower body strength and SJ (r=0.849, P<0.001), CMJ height (r=0.797, P<0.001), and chair rising time (r=-0.917, P<0.001). CONCLUSIONS: Muscle power improved after a short-term heavy resistance training, as measured by vertical jump and chair rising performance, in inactive older adults. The gains in muscle strength may contribute to the gains in chair rising time, SJ and CMJ height.