Relative Cross-Education Training Effects of Male Youth Exceed Male Adults.

ABSTRACT: Ben Othman, A, Anvar, SH, Aragão-Santos, JC, Behm, DG, and Chaouachi, A. Relative cross-education training effects of male youth exceed male adults. J Strength Cond Res 38(5): 881-890, 2024-Cross-education has been studied extensively with adults, examining the training effects on contralateral homologous muscles. There is less information on the cross-education effects on contralateral heterologous muscles and scant information comparing these responses between adults and youth. The objective was to compare cross-education training effects in male youth and adults to contralateral homologous and heterologous muscles. Forty-two male children (10-13-years) and 42 adults (18-21-years) were tested before and following an 8-week unilateral, dominant or nondominant arm, chest press (CP) training program or control group (14 subjects each). Unilateral testing assessed dominant and nondominant limb strength with leg press and CP 1 repetition maximum (1RM), knee extensors, elbow extensors (EE), elbow flexors, and handgrip maximum voluntary isometric contraction (MVIC) strength and shot put distance and countermovement jump height. Upper-body tests demonstrated large magnitude increases, with children overall exceeding adults ( p = 0.05- p < 0.0001, η2 : 0.51, 10.4 ± 11.1%). The dominant trained limb showed significantly higher training adaptations than the nondominant limb for the adults with CP 1RM ( p = 0.03, η2 : 0.26, 6.7 ± 11.5%) and EE ( p = 0.008, η2 : 0.27, 8.8 ± 10.3%) MVIC force. Unilateral CP training induced significantly greater training adaptations with the ipsilateral vs. contralateral limb ( p = 0.008, η2 : 0.93, 27.8 ± 12.7%). In conclusion, children demonstrated greater training adaptations than adults, upper-body strength increased with no significant lower-body improvements, and ipsilateral training effects were greater than contralateral training in adults.

Effects of wearing fixed orthodontic appliance on dynamic balance, reaction time, and pain perception in adolescents and young adult elite athletes.

OBJECTIVE: To investigate the effects of using fixed orthodontic appliance on dynamic balance, auditory/visual reaction times, as well as pain perception in adolescent and young adult elite athletes. METHODS: A total of 34 elite athletes (n = 19 males) aged 16-21 years from different sports (track and field sprint, long jump and discus throw) were randomly allocated to treatment (n = 17) or control (n = 17) groups. The treatment group received self-ligating brackets with 0.04 cm super-elastic nickel-titanium arch wire, placed in the brackets to correct the teeth position. Perceived pain (i.e., visual analogue scale), dynamic balance (i.e., Y balance test), and auditory reaction time and visual reaction time using Direct RT software were assessed before (day-1), and on five occasions after fixed orthodontic appliance placement (day+1, +3, +7, +14, and +30). The two groups' quantitative data [expressed as mean (standard deviation)] for each occasion were compared using the Student's t-test. Comparisons of the Y-balance test, auditory reaction time, visual reaction time, and pain visual analogue scale data were each made between the 6 occasions via a factorial A × B analysis of variance in order to check for the possible interaction between the two groups and the (6) consecutive days (occasions). RESULTS: Compared to the control group, the treatment group showed significantly (i) lower values of anterior reach for both the dominant ([78(4) vs. 75(3)%, respectively]) and the non-dominant [76(3) vs. 74(4)%, respectively] legs at day+3, and (ii) higher values of pain visual analogue scale at day+1, day+3, and day+7 [0.00(0.00) vs. 4.94(1.25); 0.00(0.00) vs. 4.12(1.17), and 0.00(0.00) vs. 0.41(0.51), respectively). Factorial analysis of variance revealed that only pain visual analogue scale values were different between the two groups at day+1 and day+3. CONCLUSION: FOA induced a high pain level during the first week following its placement in elite athletes.

Comparison of Cross-Education and Global Training Effects in Adults and Youth After Unilateral Strength Training.

ABSTRACT: Chaouachi, A, Ben Othman, A, Chaouachi, M, Hechmi, A, Farthing, JP, Granacher, U, and Behm, DG. Comparison of cross-education and global training effects in adults and youth after unilateral strength training. J Strength Cond Res 36(8): 2121-2131, 2022-Youth strength training research examining contralateral, homologous (cross-education), and heterologous (global training) effects after unilateral training have provided mixed results and the relationship to adults has not been compared. The objective was to compare adult and youth cross-education and global training effects on dominant and nondominant limb testing. Initially, 15 men and 15 prepubertal boys volunteered for each unilateral chest press (CP), handgrip training, and control groups ( n = 89). Individuals trained their dominant limb 3 times per week for 8 weeks and had their dominant and nondominant limbs tested for CP and leg press 1 repetition maximum (1RM), handgrip, knee extension and flexion, and elbow extension and flexion maximum voluntary isometric contractions (MVICs). Adult CP training gains were significantly greater than youth with lower-body testing ( p = 0.002-0.06), whereas youth CP training gains exceeded adults with upper-body tests ( p = 0.03-0.07). Training specificity was evident with greater CP 1RM increases with CP vs. handgrip training for both youth ( p < 0.0001) and adults ( p < 0.0001). Handgrip training elicited greater gains in handgrip MVICs compared with other strength tests ( p < 0.0001). In conclusion, only contralateral CP 1RM showed a training advantage for unilateral CP over unilateral handgrip training. Adults showed greater gains with lower-body testing, whereas youth showed greater gains with upper-body testing.

Resisted sprint training with partner towing improves explosive force and sprint performance in young soccer players - a pilot study.

The purpose of this study was to examine the effects of non-resisted (NRS) and partner-towing resisted (RS) sprint training on legs explosive force, sprint performance and sprint kinematic parameters. Sixteen young elite soccer players (age 16.6 ± 0.2 years, height 175.6 ± 5.7 cm, and body mass 67.6 ± 8.2 kg) were randomly allocated to two training groups: resisted sprint RS (n = 7) and non-resisted sprint NRS (n = 9). The RS group followed a six-week sprint training programme consisting of two "sprint training sessions" per week in addition to their usual soccer training. The NRS group followed a similar sprint training programme, replicating the distances of sprints but without any added resistance. All players were assessed before and after training: vertical and horizontal jumping (countermovement jump (CMJ), squat jump (SJ), and 5-jump test (5JT)), 30 m sprint performance (5, 10, and 20 m split times), and running kinematics (stride length and frequency). In the RS group significant (p < 0.05) changes were: decreased sprint time for 0-5 m, 0-10 m and 0-30 m (-6.31, -5.73 and -2.00%; effect size (ES) = 0.70, 1.00 and 0.41, respectively); higher peak jumping height (4.23% and 3.59%; ES = 0.35 and 0.37, for SJ and CMJ respectively); and 5JT (3.10%; ES = 0.44); and increased stride frequency (3.96%; ES = 0.76). In the NRS group, significant (p < 0.05) changes were: decreased sprint time at 0-30 m (-1.34%, ES = 0.33) and increased stride length (1.21%; ES = 0.17). RS training (partner towing) for six weeks in young soccer players showed more effective performances in sprint, stride frequency and lower-limb explosive force, while NRS training improved sprint performance at 0-30 m and stride length. Consequently, coaches and physical trainers should consider including RS training as part of their sprint training to ensure optimal sprint performance.

Reliability and validity of a modified Illinois change-of-direction test with ball dribbling speed in young soccer players.

The purpose of this study was to assess test-retest reliability, discriminative and criterion-related validity of the modified Illinois change-of-direction (CoD) test with ball dribbling-speed (ICODT-BALL) in young soccer players of different biological maturity and playing levels. Sixty-five young male soccer players (11.4 ± 1.2 years) participated in this study. The participants were classified according to their biological maturity (pre- and circumpeak height velocity [PHV]) and playing-level (elite and amateur players). During the test-retest time period of two weeks, the following tests were performed during week one and as retest during week two: ICODT-BALL, ICODT, 4 × 9-m shuttle-run, countermovement-jump, triple-hop-test, maximum-voluntary isometric-contraction of back-extensors, Stork, Y-Balance, 10 and 30-m sprints. The ICODT-BALL showed excellent relative (r = 0.995, p < 0.001; ICC = 0.993) and absolute (SEM < 5%; SEM < SWCs(0.2, 0.6, 1.2)) reliability. The circum-PHV (22.8 ± 1.7-s) and elite (22.5 ± 0.9-s) players showed better ICODT-BALL performance than their pre-PHV (24.2 ± 2.5-s) and amateur (25.1 ± 2.8-s) counterparts (p = 0.028 and p < 0.001, respectively). The ICODT-BALL showed "very good" (AUC = 0.81) discriminant validity when comparing the elite and amateur players, and "moderate" (AUC = 0.67) discriminant validity when compared to pre-PHV and circum-PHV boys. ICODT-BALL demonstrated "large" positive associations with the ICODT (r = 0.65; 41.8% shared-variance) and sprint tests (r ≥ 0.52; 27.3 to 34.8% shared-variance). In addition, results showed "moderate" negative associations between ICODT-BALL and strength, and power measures, as well as a "small" negative relationship with balance tests. In conclusion, the ICODT-BALL is a valid and reliable test to evaluate the ability to quickly change directions while ball dribbling in young soccer players. Therefore, practitioners can use the ICODT-BALL as a tool for talent identification.

Reliability, criterion-concurrent validity, and construct-discriminant validity of a head-marking version of the taekwondo anaerobic intermittent kick test.

This study aimed to examine the reliability and validity of a head-marking version of the taekwondo anaerobic intermittent kick test (TAIKT-head). Twenty-seven (21 males and 6 females) taekwondo athletes performed TAIKT-head on two occasions (test-retest). In addition, they performed the chest-marking version of the TAIKT (TAIKT-chest), 30-s continuous jump (CJ30s), countermovement jump (CMJ) and flexibility tests. To establish TAIKT-head's construct validity (discriminatory capability), two subgroups were identified based on their international and national taekwondo results: 15 elite (12 males and 3 females) and 12 sub-elite (9 males and 3 females) athletes. TAIKT-head showed high relative (ICCs ≥ 0.90) and absolute (SEMs < SWCs) reliability. The comparison between TAIKT-head and TAIKT-chest revealed that absolute and relative peak and mean powers were higher (p < 0.001) in TAIKT-head than in TAIKT-chest. In contrast, the fatigue index and rating of perceived exertion were lower in TAIKT-head than in TAIKT-chest (p < 0.001 and p < 0.01, respectively), with no significant difference between the two tests regarding physiological variables. Significant correlations between TAIKT-head and TAIKT-chest (r ranged from 0.74 to 0.53), CJ30s (r ranged from 0.84 to 0.43), and CMJ (r ranged from 0.88 to 0.79) were mostly "very large". There was no association between TAIKT-head and flexibility tests. Elite athletes showed greater TAIKT-head performances than sub-elite counterparts. Receiving operating characteristic analysis indicated that the TAIKT-head effectively discriminated between elite and sub-elite athletes. In conclusion, the TAIKT-head is a reliable and valid test to evaluate the specific intermittent anaerobic power of taekwondo athletes through the most used kicking technique at the head level.

Ramadan intermittent fasting induced poorer training practices during the COVID-19 lockdown: A global cross-sectional study with 5529 athletes from 110 countries.

Ramadan intermittent fasting during the COVID-19 lockdown (RIFL) may present unique demands. We investigated training practices (i.e., training load and training times) of athletes, using pre-defined survey criteria/questions, during the 'first' COVID-19 lockdown, comparing RIFL to lockdown-alone (LD) in Muslim athletes. Specifically, a within-subject, survey-based study saw athletes (n = 5,529; from 110 countries/territories) training practices (comparing RIFL to LD) explored by comparative variables of: sex; age; continent; athlete classification (e.g., world-class); sport classification (e.g., endurance); athlete status (e.g., professional); and level of training knowledge and beliefs/attitudes (ranked as: good/moderate/poor). During RIFL (compared to LD), athlete perceptions (ranges presented given variety of comparative variables) of their training load decreased (46-62%), were maintained (31-48%) or increased (2-13%). Decreases (≥ 5%, p < 0.05) affected more athletes aged 30-39 years than those 18-29 years (60 vs 55%); more national than international athletes (59 vs 51%); more team sports than precision sports (59 vs 46%); more North American than European athletes (62 vs 53%); more semi-professional than professional athletes (60 vs 54%); more athletes who rated their beliefs/attitudes 'good' compared to 'poor' and 'moderate' (61 vs 54 and 53%, respectively); and more athletes with 'moderate' than 'poor' knowledge (58 vs 53%). During RIFL, athletes had different strategies for training times, with 13-29% training twice a day (i.e., afternoon and night), 12-26% at night only, and 18-36% in the afternoon only, with ranges depending on the comparative variables. Training loads and activities were altered negatively during RIFL compared to LD. It would be prudent for decision-makers responsible for RIFL athletes to develop programs to support athletes during such challenges.

Unilateral Elbow Flexion and Leg Press Training Induce Cross-Education But Not Global Training Gains in Children.

PURPOSE: Whereas cross-education has been extensively investigated with adults, there are far fewer youth investigations. Two studies suggested that children had greater global responses to unilateral knee extensor fatigue and training, respectively, than adults. The objective of this study was to compare global training responses and cross-education effects after unilateral elbow flexion (EFlex) and leg press (LP) training. METHODS: Forty-three prepubertal youths (aged 10-13 y) were randomly allocated into dominant LP (n = 15), EFlex (n = 15) training groups, or a control (n = 13). Experimental groups trained 3 times per week for 8 weeks and were tested pretraining and posttraining for ipsilateral and contralateral 1-repetition maximum LP; knee extensor, knee flexors, elbow flexors; and handgrip maximum voluntary isometric contractions (MVIC), and countermovement jump. RESULTS: In comparison to no significant changes with the control group, dominant elbow flexors training demonstrated significant ( P < .001) improvements only with ipsilateral and contralateral upper body testing (EFlex MVIC [15.9-21.5%], EFlex 1-repetition maximum [22.9-50.8%], handgrip MVIC [5.5-13.8%]). Dominant LP training similarly exhibited only significant ( P < .001) improvements for ipsilateral and contralateral lower body testing (LP 1-repetition maximum [59.6-81.8%], knee extensor MVIC [12.4-18.3%], knee flexor MVIC [7.9-22.3%], and countermovement jump [11.1-18.1%]). CONCLUSIONS: The ipsilateral and contralateral training adaptations in youth were specific to upper or lower body training, respectively.

Leg asymmetry and muscle function recovery after anterior cruciate ligament reconstruction in elite athletes: a pilot study on slower recovery of the dominant leg.

The aim of this study was to examine performance in hopping tests in male athletes after anterior cruciate ligament reconstruction (ACLR) in the 4-to-6 months post-surgery period. A total of 36 athletes (24 ACLR and 12 controls) participated in this study. The ACLR group consisted of athletes who had undergone an ACLR on their dominant side (ACL DG n=16) or non-dominant side (ACL NDG n=8). Participants completed the following functional tests: a single-leg hop (SLH), single-leg triple hop (SL3H) and single-leg counter movement jump (SLCMJ), then the limb symmetry index (LSI) was calculated. There were no significant differences between the dominant and the non-dominant legs for all functional tests when comparing the ACL DG and the ACL NDG at 6 months after surgery. At 6 months after ACLR, the LSI of the two legs was within acceptable values, whether the athlete had the operation on their dominant or non-dominant leg (except the mean LSI for the ACL DG in the SLCMJ test). Furthermore, the control group showed higher performances as compared to the ACL group for all variables at 6 months after surgery, despite acceptable LSI. We concluded that an early return to "full participation to training" is not recommended in participants who have undergone an ACLR with patellar tendon grafts.

Racial differences in hemoglobin and plasma volume variation: implications for muscle performance and recovery.

Objective: To examine the effect of race differences on sprint performance, Hemoglobin (Hb), Hematocrit (Ht) and plasma volume (PV) variation in response to repeated sprint exercise. Design: Thirty-six healthy, moderately trained men and women (20.8 ± 0.2 year-old) volunteered to participate in this study. They were allocated to one of the four groups according to their gender and race: Black men's group (BM, n = 9), White men's group (WM, n = 9), Black women's group (BW, n = 9) and White women's group (WW, n = 9). All participants performed the running-based anaerobic sprint test (RAST), which consists of six 35-m sprints with 10 s of recovery in-between. Six venous blood samples were collected to determine Hb, Ht and PV levels at rest, after warm-up, immediately post- and at 5, 15 and 30 min post-RAST. Blood lactate is also sampled during the 3rd minutes of recovery. Results: The best running time was significantly shorter (P = .002) in BW compared to WW. We have observed significantly higher Hb (P = .010) and Ht (P = .004) levels in BW compared to WW during the 5th minute of recovery. During RAST, the PV decreased significantly (P = .007) in WM only. Black groups had lower (P < .05) lactate levels compared to the white subjects. During recovery, PV increase was significantly (P = .003) higher in WW compared to BW during the 5th minute of recovery. Conclusion: This study demonstrated that sprint and repeated sprint performances were different between white and black women. Differences in anaerobic performance between the groups were associated with racial differences in lactate levels and blood count among women's group during recovery time. Hence, it is important to take into account this race-related difference in hematological parameters in responses to intense efforts.

Global Training Effects of Trained and Untrained Muscles With Youth Can be Maintained During 4 Weeks of Detraining.

Chaouachi, A, Ben Othman, A, Makhlouf, I, Young, JD, Granacher, U, and Behm, DG. Global training effects of trained and untrained muscles with youth can be maintained during 4 weeks of detraining. J Strength Cond Res 33(10): 2788-2800, 2019-Global (whole-body) effects of resistance training (i.e., cross-education) may be pervasive with children. Detraining induces less substantial deficits with children than adults. It was the objective of this study to investigate the global responses to 4 weeks of detraining after 8 weeks of unilateral leg press (LP) training in 10-13-year-old, pre-peak-height-velocity stage boys. Subjects were randomly separated into 2 unilateral resistance training groups (high load/low repetitions [HL-LR] and low load/high repetitions [LL-HR], and control group). Assessments at pre-training, post-training, and detraining included dominant and nondominant limbs, unilateral, 1 repetition maximum (1RM) and 60% 1RM LP, knee extension, knee flexion, elbow flexion, and handgrip maximal voluntary isometric contraction (MVIC), and countermovement jump (CMJ). All measures significantly increased from pre-test to detraining for both training programs, except for elbow flexion MVIC with increases only with HL-LR. All measures except CMJ and handgrip MVIC significantly decreased from post-test to detraining, except for elbow flexion MVIC with decreases only with HL-LR. The dominant trained limb experienced significantly greater LP improvements (pre- to detraining) and decrements (post- to detraining) with LP 1RM and 60% 1RM LP. In conclusion, youth HL-LR and LL-HR global training effects of trained and untrained limbs demonstrate similar benefits (pre- to detraining) and decrements (post- to detraining) with detraining. The findings emphasize that training any muscle group in a child can have positive global implications for improved strength and power that can persist over baseline measures for at least a month.

Maturity Status as a Determinant of the Relationships Between Conditioning Qualities and Preplanned Agility in Young Handball Athletes.

Hammami, R, Sekulic, D, Selmi, MA, Fadhloun, M, Spasic, M, Uljevic, O, and Chaouachi, A. Maturity status as a determinant of the relationships between conditioning qualities and preplanned agility in young handball athletes. J Strength Cond Res 32(8): 2302-2313, 2018-Studies performed thus far have not accounted for the potential influence of maturity on determinants of preplanned agility. This study aimed to examine how determinants of preplanned agility are affected by the period of peak height velocity (PHV) regarding the anthropometrics and conditioning qualities in young handball players. The sample comprised 56 handball players (male; 12-14 years of age), allocated into 2 groups according to their biological age of maturity: Pre-PHV (N = 34) and Post-PHV (N = 22). Players were evaluated on handball-specific tests of preplanned agility (CODAT and T-HALF). Predictors included anthropometrics, sprinting, horizontal and vertical jumps, and reactive strength index (RSI). The reliability of the tests was appropriate (intraclass correlation coefficient: 0.87-0.95; coefficient of variation: 4.4-5.8%). In the Pre-PHV group, 67% variance of the T-HALF accounted for horizontal countermovement jump (ß: -0.83, p < 0.01), 20-m sprint (ß: 0.91, p < 0.01), and body mass (ß: 0.19, p = 0.02). In the Post-PHV group, 80% of the T-HALF variance was explained, with a significant influence of 20-m sprint (ß: 0.52, p < 0.01), RSI (ß: -0.24, p = 0.04), and standing long jump (ß: -0.57, p = 0.03). In the Pre-PHV group, 45% of the CODAT variance accounted for the partial influence of body fat percentage (ß: 0.44, p = 0.04) and a 20-m sprint (ß: 0.74, p < 0.01). In the Post-PHV group, the predictors accounted for 79% of the CODAT variance, with a significant influence of the RSI (ß: -0.26, p = 0.04) and a 10-m sprint (ß: 0.87, p = 0.03). Our results reinforce the need for differential strength and conditioning programs aimed at improving the preplanned agility of young athletes who differ in maturity status.

Assessment of premature ventricular beats in athletes.

INTRODUCTION: Premature ventricular complexes (PVC) are generally considered as a benign electrocardiographic abnormality in the athleticpopulation. However it may be indicative of underlying heart disease which may increase the risk of sudden death. This implies the need forcardiological evaluation before indicating the ability to practice competitive sports. AIM: The aim of this study was to evaluate an athlete population with PVC and establish underlying etiologies in order to take a decisionregarding practicing sports. METHODS: This is a prospective study which included athletes examined in the Tunisian National Centre of Sports Medicine and Sports Science (TNCSM) from January 2013 to June 2015 who presented PVC on an electrocardiogram RESULTS: 5798 athletes were referred to the TNCSM . We identified 42 athletes having PVC with a prevalence of 1.8%. The average age of thestudy population was 21.6 ± 5.99 years. 83% were men. 88% were asymptomatic the electrocardiogram was considered normal in 62% ofthe athletes according to the Seattle criteria, At the Holter monitoring, the average number of PVC was 920 PVC / 24 hours. Thirteen athleteshad doublets and 11 had triplets. One patient had polymorphic PVC and an R/T phenomenon. The transthoracic echocardiography (TTE) wasnormal in 71 % of cases. Three athletes had hypertrophic cardiomyopathy (HCM). All patients underwent a stress test. The PVC disappearedin 12% of athletes. MRI was performed in 10 athletes confirming the three cases of HCM and revealing a case of arrhythmogenic rightventricular dysplasia and a case of compression of the right ventricle by pectusexacavatum. CONCLUSION: After this assessment, five athletes were not allowed to practice sport. This study shows the necessity of a thorough cardiological assessment of athletes with ventricular arrhythmia in order to detect underlying heart disease and prevent sudden death in this young apparentlyhealthy population.

Benefits of a regular vs irregular rhythm-based training programme on physical fitness and motor skills in obese girls.

PURPOSE: The aim of the current study was to examine the impact of a physical exercise programme including rhythmic elements (regular and irregular tempos) on physiological variables, motor skills (MS), and jump performances in obese girls. METHODS: Thirty-six obese girls (age: 10.4 ± 0.9 years, body mass: 58.7 ± 4.0 kg, height: 1.37 ± 0.04 m, body mass index: 31.2 ± 2.1) participated in three weekly physical exercise sessions for 6 weeks, with each session consisting of basic fundamental locomotor movements. The participants were divided into two groups: a control group (CG) and an experimental group (EG). CG performed the exercise in a quiet setting (i.e., without rhythmic accompaniment), whereas regular and irregular rhythmic accompaniments were prescribed in EG. The physical exercise programme included three sessions per week for 6 weeks. Each session was composed of three parts: 15 min of warm-up, followed by 40 min of exercises based on basic locomotor movements (i.e., running, hopping, skipping, jumping, leaping, sliding, galloping, throwing, catching, kicking, dribbling, and striking) and then 5 min of stretching. Each exercise was demonstrated by the teacher. Before and after the intervention period, cardiovascular measures (i.e., resting blood pressures, recovery for heart rate and systolic blood pressure, and recovery rate-pressure product) were made and five MS (i.e., running, hopping, leaping, jumping and dribbling) were evaluated in two conditions (i.e., during exercise with regular and irregular tempos). Moreover, performances on vertical jump tests (squat and countermovement jump tests) were measured. RESULTS: EG exhibited greater improvement in MS with a regular tempo (and sometimes an irregular tempo), cardiovascular components, and jump performances. CONCLUSION: These findings demonstrate that physical exercise at various tempos is useful for improving physical fitness, developing MS, and thus probably preventing obesity complications.

Morning-evening difference of team-handball-related short-term maximal physical performances in female team handball players.

This study investigated the two different time-of-day effect on team-handball-related short-term maximal physical performances. At two different time-of-day, fifteen young female team handball players performed different physical tests: HandGrip (HG) test, Ball-Throwing Velocity (BTV) test, Modified Agility T-test (MAT) and Repeated Shuttle-Sprint and Jump Ability (RSSJA) test. Rating of perceived exertion (RPE) scale was determined following the termination of the last test. Measurements were performed at two separate testing sessions (i.e., in the morning (7:00-8:30 h) and in the early evening (17:00-18:30 h)) in a randomised and counter-balanced setting on non-consecutive days. The results showed that HG (P = 0.0013), BTV (P = 0.0027) and MAT (P < 0.001) performances were better in the evening compared with the morning. During RSSJA, both best and mean sprint times were shorter in the evening compared to the morning (P < 0.001). Moreover, during the latter test, mean jump performance was higher in the evening compared to the morning (P = 0.026). However, there was no morning-evening difference in the best jump performance during RSSJA. Likewise, jump performance decrement was not affected by the time-of-day of testing. On the other hand, RPE fluctuated, with morning nadirs and afternoon/early evening highest values. The findings suggest that in female team handball players, team-handball-related short-term maximal physical performances were better in the afternoon than in the morning.

Effects of Psyching-Up on Sprint Performance.

Hammoudi-Nassib, S, Nassib, S, Chtara, M, Briki, W, Chaouachi, A, Tod, D, and Chamari, K. Effects of psyching-up on sprint performance. J Strength Cond Res 31(8): 2066-2074, 2017-The present research aimed at examining whether the psyching up (PU) strategies improve performance in 30-m sprinting. Sixteen male sprinters (age, 20.6 ± 1.3 years; body mass, 77.5 ± 7.1 kg; height, 180.8 ± 5.6 cm) participated in this study. Before each experimental session, the Hooper index was used to monitor the subject's feeling for the quality of sleep of the previous night, perceived quantity of stress, delayed onset muscle soreness, and fatigue. After completing general and specific warm-up, participants had to rate their degree of self-confidence. Then, they were asked to follow 1 of these 4 conditions: Imagery (experimental PU condition), Preparatory arousal (experimental PU condition), Attention placebo (control condition), and Distraction (control condition) during the final 30 seconds of the rest period right before performing a 30-m sprint. Participants separately and randomly performed all conditions. Results showed that although the imagery and preparatory arousal strategies contributed to increase the performance in the short-distance sprints (from 0 to 10 m), the imagery strategy contributed to increase the performance in the 30-m sprints. These findings support the general view that the PU strategies could improve athletic performance.

Within Session Sequence of Balance and Plyometric Exercises Does Not Affect Training Adaptations with Youth Soccer Athletes.

The integration of balance and plyometric training has been shown to provide significant improvements in sprint, jump, agility, and other performance measures in young athletes. It is not known if a specific within session balance and plyometric exercise sequence provides more effective training adaptations. The objective of the present study was to investigate the effects of using a sequence of alternating pairs of exercises versus a block (series) of all balance exercises followed by a block of plyometric exercises on components of physical fitness such as muscle strength, power, speed, agility, and balance. Twenty-six male adolescent soccer players (13.9 ± 0.3 years) participated in an 8-week training program that either alternated individual balance (e.g., exercises on unstable surfaces) and plyometric (e.g., jumps, hops, rebounds) exercises or performed a block of balance exercises prior to a block of plyometric exercises within each training session. Pre- and post-training measures included proxies of strength, power, agility, sprint, and balance such as countermovement jumps, isometric back and knee extension strength, standing long jump, 10 and 30-m sprints, agility, standing stork, and Y-balance tests. Both groups exhibited significant, generally large magnitude (effect sizes) training improvements for all measures with mean performance increases of approximately >30%. There were no significant differences between the training groups over time. The results demonstrate the effectiveness of combining balance and plyometric exercises within a training session on components of physical fitness with young adolescents. The improved performance outcomes were not significantly influenced by the within session exercise sequence.

Associations Between Balance and Muscle Strength, Power Performance in Male Youth Athletes of Different Maturity Status.

Balance, strength and power relationships may contain important information at various maturational stages to determine training priorities. PURPOSE: The objective was to examine maturity-specific relationships of static/dynamic balance with strength and power measures in young male athletes. METHODS: Soccer players (N = 130) aged 10-16 were assessed with the Stork and Y balance (YBT) tests. Strength/power measures included back extensor muscle strength, standing long jump (SLJ), countermovement jump (CMJ), and 3-hop jump tests. Associations between balance with strength/power variables were calculated according to peak-height-velocity (PHV). RESULTS: There were significant medium-large sized correlations between all balance measures with back extensor strength (r = .486-.791) and large associations with power (r = .511-.827). These correlation coefficients were significantly different between pre-PHV and circa PHV as well as pre-PHV and post-PHV with larger associations in the more mature groups. Irrespective of maturity-status, SLJ was the best strength/power predictor with the highest proportion of variance (12-47%) for balance (i.e., Stork eyes opened) and the YBT was the best balance predictor with the highest proportion of variance (43-78%) for all strength/power variables. CONCLUSION: The associations between balance and muscle strength/power measures in youth athletes that increase with maturity may imply transfer effects from balance to strength/power training and vice versa in youth athletes.

Effect of leg dominance on change of direction ability amongst young elite soccer players.

Young soccer players often use one particular dominant leg (DL) to perform dynamic movements which require strength, resulting in leg asymmetry. The aim of this study was to compare, in young soccer players, the effect of using DL and non-dominant leg (NDL) on time performance of two change of direction (COD) manoeuvres in several angles of COD. Seventy-three young male soccer players (mean ± SD, age: 16.1 ± 1.8 year) participated in this study. Players performed 10-m sprints, either in a straight line or with a COD (5 m straight ahead and a turn of 45°, 90°, 135° and 180° to the opposite side of the DL or NDL). Testing for COD speed was conducted over two different manoeuvres: (1) sidestepping and (2) bypass. Maximal isometric voluntary contraction of the knee extensors/flexors and hip abductors/adductors was also measured using a handheld dynamometer. For sidestepping, COD performance with use of the DL was significantly better compared to the NDL (P < 0.05) in all angles of COD. However, bypass COD performance through use of the DL was better compared to the NDL only when turning at 135°. Additionally, strength of the knee extensors/flexors and hip abductors of the DL was significantly (P < 0.05) greater than the NDL. The use of the DL allows better COD performance than the NDL when sidestepping manoeuvre is used. However, the DL allows better COD performance than the NDL only at 135° with the use of the bypass manoeuvre. Furthermore, the greater strength of the DL compared to the NDL may contribute to COD performance difference between legs.