Hasil untuk "cond-mat.supr-con"

X. Ye, Cassandra Hale, Emma-Kate Brown et al.

ABSTRACT Ye, X, Hale, C, Brown, E, Clausi, E, Hudak, J, Marino, A, and Mezanko, T. Effects of percussion massage therapy on neuromuscular recovery from eccentric exercise-induced muscle damage. J Strength Cond Res XX(X): 000-000, 2025-The aim of this study was to examine the effects of percussion massage intervention on neuromuscular function and performance recovery from eccentric exercise-induced muscle damage. Twenty healthy and physically active volunteers underwent an elbow flexion eccentric exercise protocol (6 sets of 10 repetitions with 80% of the concentric one-repetition maximum) with their nondominant arms. The indirect markers of muscle damage (muscle soreness, elbow flexion range of motion, upper arm circumference, elbow flexion isometric strength along with voluntary activation percentage, and resting twitch) were measured before, immediately, and 24, 48, and 168 hours after the eccentric exercise. The subjects were randomly assigned to either (a) percussion massage group (Percussion, n = 10): received 5 minutes of percussion massage treatment at the end of the eccentric exercise visit, the end of 24 hours, and the end of 48 hours after the exercise, or (b) control group (CON, n = 10): did not receive any treatment. Separate 2-way (time × group) mixed factorial analysis of variance tests were used to examine the potential changes of muscle damage indirect markers across time between groups. Significant main effects for time were observed in all dependent variables (p < 0.05); however, no interactions or group differences were found in any of these variables. Therefore, our study suggests that using percussion massage does not accelerate recovery after high-intensity muscle damaging eccentric exercise.

T. Kvorning, Daniel S Karkov, Christian S Luno et al.

ABSTRACT Kvorning, T, Karkov, DS, Luno, CS, Dinesen, NM, Jørgensen, AN, Gejl, KD, Blazevich, AJ, and Aagaard, P. Morning-based resistance exercise improves afternoon jumping performance, stretch-shortening-cycle muscle power, and lower limb stiffness in top-level ice hockey players. J Strength Cond Res 40(1): e26-e31, 2026-Precompetition training (PCT) performed as nonexhaustive bouts of morning-based resistance exercise (e.g., resistance priming) may positively affect afternoon physical performance. Specifically, experimental evidence points toward improved force- and power-related performance. The present study aimed to examine the effect of a morning PCT session on afternoon mechanical muscle function, as reflected by changes in maximal isolated isometric knee extensor (KE) strength (maximal voluntary contraction), and KE rapid force capacity (rate of force development: RFD), countermovement jump (CMJ) kinematics and kinetics, and lower limb stiffness (LLS). Fifteen Danish elite ice hockey players from the U20 National Team (18-20 years) performed (a) a PCT test day consisting of a back squat-lift session of 4 sets of 3 repetitions, with a maximal intentional speed at 50, 65, 75, and 85% 1 repetition maximum, respectively, in the morning (9:00 hours) followed by CMJ and KE testing in the afternoon (15:00 hours), and (b) a control (CON) test day consisting of afternoon (15:00 hours) testing only. Results showed that enhanced stretch-shortening-cycle (SSC) muscle function was observed during CMJ testing after PCT compared with CON (p ≤ 0.05), as evidenced by increases (p < 0.05) in maximal jump height (+3.5% [0.5-6.5]), peak vertical ground reaction force in the descending phase (+5.1% [0.3-9.9]), take-off impulse in the ascending phase (+1.6% [0.2-3.1]), LLS (+23.1 [-4.3 to 50.6]), and mean ascending take-off power (+4.8% [1.7-7.9]). In contrast, PCT did not elicit changes in KE strength or RFD. In conclusion, morning-based PCT in the form of lower-body resistance exercise improves lower limb SSC muscle function later in the day in this cohort of high-level athletes.

Bryson F. Trask, Tony R. Montgomery, Coleman Honea et al.

Trask, BF, Montgomery, TR Jr, Honea, C, Remotigue, EB, Sears, KN, Hammer, SM, and Dinyer-McNeely, TK. Increasing eccentric proportion of repetitions leads to increased time to task failure. J Strength Cond Res 39(8): 837–844, 2025—This study examined the effect of altered concentric (CON) and eccentric (ECC) phases of a repetition on repetitions completed, performance fatigability, electromyographic (EMG) amplitude (AMP), and mean power frequency (MPF), and muscle oxygen saturation (SAT). Subjects ( n = 23) performed fatiguing, single-limb leg extension at 40% 1 repetition maximum at 3 cadences: 3sCON,1sECC (3C:1E), 1sCON, 3sECC (1C:3E), 2sCON, 2sECC (2C:2E). A 1-way (cadence: 1C:3E, 3C:1E, 2C:2E) repeated-measures ANOVA examined differences in repetitions completed and performance fatigability (%Δ pre–post exercise maximal voluntary isometric contraction force). Separate 2 (phase: CON, ECC) × 3 (cadence: 1C:3E, 3C:1E, 2C:2E) repeated-measures ANOVAs examined differences in %Δ for EMG AMP, EMG MPF, and SAT . Significance was set at p < 0.05. More repetitions were completed during 1C:3E (20 ± 3) than during 2C:2E (18 ± 3, p = 0.006) and 3C:1E (16 ± 3, p < 0.001). Performance fatigability was similar between cadences (3C:1E: −37 ± 11%, 1C:3E: −41 ± 9%, 2C:2E: −38 ± 11%, p = 0.414). The %Δ in EMG AMP was greater during CON (61.1 ± 28.4%) than during ECC (40.2 ± 34.2%, p < 0.001). The %Δ in EMG MPF was similar between phases ( p = 0.706) and cadences ( p = 0.494). %Δ in SAT was greater during CON (−12.0 ± 5.8%) than during ECC (−10.0 ± 5.1%, p < 0.001). Decreasing CON and increasing ECC proportion within a repetition extended the time to task failure. This adjustment allows practitioners to prolong exercise bouts without significantly altering acute neuromuscular or muscle oxygen SAT responses. These findings may be particularly useful in rehabilitation or athletic settings, because incorporating a higher proportion of ECC phase can enhance muscular endurance and improve resistance to fatigue during a single bout of exercise.

Courtney E. Wheelock, Elizabeth M. Lavoie, J. L. Pryor et al.

ABSTRACT Wheelock, CE, Lavoie, EM, Pryor, JL, Pryor, RR, Colburn, D, Johnson, BD, and Hostler, D. The effect of a single session of postexercise hot water immersion on same day aerobic performance and recovery status. J Strength Cond Res XX(X): 000-000, 2025-Postexercise hot water immersion (HWI) passively induces high thermal loads, but its acute effect on subsequent exercise is unknown. The purpose of this study was to evaluate aerobic performance and recovery status after a single HWI session. Twelve subjects (6 males; V̇o2peak: 44.9 ± 5.9 ml·kg-1·min-1) completed 3 randomized trials. Two trials were exercise with 30 minutes of HWI (39°C) followed by an identical exercise session 8 h (HWI-8; n = 12) or 24 h (HWI-24; n = 12) later. In the control (CON; n = 12), subjects rested after exercise and completed the second exercise session 8 h later. Movement economy (ME) was measured on a treadmill at 3 stages (6.0, 8.0, and 10.0 km·h-1) followed by a 15-minute running time trial (TT) for maximum distance. Plasma volume change (ΔPV) from baseline was calculated. Perceived recovery was measured before the second exercise session. Independent effects of HWI (HWI-8 vs. CON) and HWI recovery time (HWI-8 vs. HWI-24) were assessed. Significance was accepted at p ≤ 0.05. As expected, HWI induced a greater thermal load after exercise compared with CON (p < 0.001). Hot water immersion induced greater body mass loss and sweat rates, but did not affect ΔPV compared with CON. After 8 h of recovery, ME and TT distance during HWI-8 (2.4 ± 0.4 km) was similar to CON (2.5 ± 0.4 km; p = 0.10), though TT declined by 3.8 ± 5.8% after HWI during same day exercise. Hot water immersion-24 TT (2.6 ± 0.5 km; p < 0.01) and subjective recovery (p < 0.01) were greater than HWI-8, while ME was not different. This study saw no effect of a single 30-minute HWI on ME, TT performance, or ΔPV compared with control. Increased running performance and perceived recovery status were observed 24 h compared with 8 h after HWI.

Timothy D. Griest, Cameron M. McCarthy, Liliana I Rentería et al.

Abstract Griest, TD, McCarthy, CM, Rentería, LI, Paterson, KGP, Eurich, DF, Laskin, GR, and Ormsbee, MJ. Supramaximal walkouts protect against performance decrements experienced in repeated sets of back squats. J Strength Cond Res 39(6): 617–624, 2025—The purpose of this study was to determine whether performing supramaximal walkouts (SMW) enhances subsequent repeated back squat performance. Thirteen resistance-trained men (age: 23.2 ± 3.0 years, 1 repetition maximum [1RM] back squat: 2.1 ± 0.4 kg·bodymass−1) completed 2 trials in a randomized, counterbalanced, crossover design. Each trial began with 1 back squat at 92.5% 1RM (PRE). Five minutes post-PRE, subjects un-racked either 110% 1RM (SMW) or 30% 1RM (CON) for a 10-second hold. After 5 minutes rest, 3 sets of 1 back squat at 92.5% 1RM were completed with 5 minutes between each. Performance and muscle activation indicators were measured during each repetition. All data were analyzed through Friedman's 2-way ANOVA by ranks. Significance was set at p 0.219). In addition, rating of perceived exertion was elevated at POST2 following CON (p = 0.044), while there were no differences with SMW (p = 0.716). Peak power, peak velocity, and electromyography amplitude of the vastus lateralis and gluteus maximus were unaltered (p > 0.077). Performing an SMW at 110% 1RM before back squats may attenuate performance decrements resulting from repeated repetitions for 1 set and, therefore, could be used to maintain performance for 1 additional set during training.

Keisuke Shibata, Taichi Yamaguchi, Kota Shimamori et al.

Abstract Shibata, K, Yamaguchi, T, Shimamori, K, Yamazaki, Y, Takizawa, K, and Nosaka, K. One-repetition maximum and repetitions to failure at submaximal intensity in eccentric-only, concentric-only, and conventional arm curl, bench press, and back squat exercises. J Strength Cond Res 39(5): 515–522, 2025—The present study compared eccentric-only (ECC-only), concentric-only (CON-only), and eccentric-concentric (ECC-CON) arm curl (AC), bench press (BP), and back squat (BSQ) exercises for 1 repetition maximum (1RM) and repetitions to failure (RF) to delineate characteristics of ECC-only exercises. Twelve resistance-trained young men participated in 7 sessions. In session 1, 1RM of ECC-CON was determined for AC, BP, and BSQ. In session 2, ECC-CON 1RM for the 3 exercises were reassessed, and RF of ECC-CON at 80% of ECC-CON 1RM load was examined for the exercises. In sessions 3 and 4, RF of ECC-only and CON-only at 80% of ECC-CON 1RM load was determined. In session 5, ECC-only 1RM and CON-only 1RM were assessed for the exercises. In sessions 6 and 7, RF of ECC-only and CON-only at 80% of respective 1RM load was measured. The 1RM was greater (p < 0.01) for ECC-only (AC: 19.3 ± 3.6 kg, BP: 103.3 ± 18.2 kg, BSQ: 141.3 ± 17.5 kg) than for CON-only (AC: 14.6 ± 2.9 kg, BP: 82.3 ± 16.2 kg, BSQ: 113.8 ± 14.5 kg) and for ECC-CON (AC: 14.3 ± 3.2 kg, BP: 87.1 ± 16.2 kg, BSQ: 119.2 ± 16.1 kg) with a significant difference between CON-only and ECC-CON for BP only. The RF was greater (p < 0.01) in ECC-only than in CON-only and ECC-CON at 80% of ECC-CON 1RM and respective 80% 1RM load for all 3 exercises (e.g., BP at 80% of respective 1RM load, ECC-only: 14.5 ± 4.6, CON-only: 10.0 ± 3.3, ECC-CON: 10.3 ± 2.1 repetitions). These results suggest that greater loads can be handled in ECC-only with less fatigue than others, and this provides advantages for eccentric-only resistance exercises.

M. Hoshikawa

ABSTRACT Hoshikawa, M. Effects of nightly electronic device restriction and morning bright light on sleep, mood, and performance among elite athletes. J Strength Cond Res XX(X): 000-000, 2025-This study aimed to evaluate whether restriction of electronic device use before bedtime and morning bright-light exposure influences sleep, sleepiness, mood, and performance parameters among elite athletes. Twenty-five elite athletes (24 international level and 1 national level) were divided into 2 groups: with (INT; n = 12) and without (CON; n = 13) intervention. The INT turned off their electronic devices 30 minutes before bedtime and were exposed to morning bright light (approximately 10,000 lux) for 20 minutes after waking. Their nocturnal sleep parameters, Karolinska sleepiness scale, subjective sleep quality, fatigue, and heart rate immediately after waking were monitored every morning for 2 weeks. The Epworth sleepiness scale (ESS) score, Profile of Mood States (POMS) vigor and fatigue scores, reaction time, isometric grip strength, squat jump (SJ) height, rebound jump (RJ) height, RJ index, and heart rate during aerobic exercise were evaluated before and after the 2-week period. The RJ index was calculated as RJ height (m)/ground contact time (sec). For the INT, POMS vigor score (p < 0.001), reaction time (p = 0.016), RJ height (p = 0.001), and RJ index (p < 0.001) improved without any change in sleep parameters. The improvements in ESS score and SJ height seemed to be greater in the INT group, but the interactions did not reach a significant level (p < 0.10). No statistically significant interaction was observed in the exercise heart rate and isometric grip strength. Two weeks of 30 minutes nighttime electronic device restriction and 20 minutes morning bright-light exposure improved mood and some performance parameters among elite athletes. However, the intervention did not change athletes' sleep parameters.

Ryo Kataoka, J. Song, Yujiro Yamada et al.

Abstract Kataoka, R, Song, JS, Yamada, Y, Hammert, WB, Seffrin, A, Spitz, RW, Wong, V, Kang, A, and Loenneke, JP. The impact of different ischemic preconditioning pressures on pain sensitivity and resistance exercise performance. J Strength Cond Res 38(5): 864–872, 2024—To determine (a) the impact of ischemic preconditioning pressures (applied as a % of arterial occlusion pressure [AOP]) on pressure pain threshold (PPT) and resistance exercise performance and (b) whether changes in performance could be explained by changes in PPT. Subjects (n = 39) completed 4 protocols in a randomized order: (a) ischemic preconditioning (IPC) at 110% AOP (IPC 110%), (b) IPC at 150% AOP (IPC 150%), (c) IPC at 10% AOP (Sham), and (d) time-matched control (CON). Each protocol included 4 cycles of 5 minutes of occlusion followed by 5 minutes of reperfusion. Pressure pain threshold was taken before and after. Discomfort ratings were given at the end of each cycle. Every visit finished with 2 sets of 75-second maximal isokinetic unilateral elbow flexion or extension. Overall, IPC 110% and IPC 150% resulted in similar increases in PPT relative to CON [110%: difference of 0.36 (0.18, 0.54) kg·m−2; 150%: difference of 0.377 (0.15, 0.59) kg·m−2] and Sham. Both resulted in greater discomfort than Sham and CON, with IPC 150% inducing greater discomfort than IPC 110% (BF10: 14.74). There were no differences between the conditions for total work (BF10: 0.23), peak torque (BF10: 0.035), or average power (BF10: 0.159). We did not find evidence that PPT mediated performance. We did not detect changes in performance with 2 different relative pressures greater than AOP. Our mean applied pressures were lower than those used previously. There might be a minimal level of pressure (e.g., >150% of AOP) that is required to induce ergogenic effects of ischemic preconditioning.

D. Kolinger, P. Šťastný, A. Pisz et al.

Abstract Kolinger D, Stastny P, Pisz A, Krzysztofik M, Wilk M, Tsoukos A, and Bogdanis GC. High-intensity conditioning activity causes localized postactivation performance enhancement and nonlocalized performance reduction. J Strength Cond Res 38(1): e1–e7, 2024—This study aimed to examine whether a conditioning activity (CA) performed by the legs (barbell back squat) may cause postactivation performance enhancement (PAPE) on muscle groups other than leg extensors in isokinetic (eccentric [ECC] and concentric [CON]) and dynamic movement. Twelve male basketball players (age: 21.3 ± 3.2, body mass: 89.6 ± 14.1 kg, height: 187.4 ± 4.6 cm, and 1 repetition maximum (1RM) barbell back squat: 113 ± 21 kg) with previous resistance-training experience of at least 2 years, performed 3 sets of 3–4 repetitions of back-squats with submaximal load (60, 90, and 90% 1RM) as CA. Before and after the CA, they performed pretest and post-test in the form of countermovement jumps (CMJs) (localized) or explosive push-ups (EPUs) (nonlocalized) along with isokinetic flexion and extension at the knee (localized) or at the elbow (nonlocalized). The localized and nonlocalized protocols were divided into 2 days in a randomized order. The back squat as CA significantly increased peak torque (PT) (p 0.8) and medium (0.4–0.79) effect sizes and significantly decreased (p 0.05) between premeasures and postmeasures of take-off height. The effect of PAPE seems to be specific to the muscles most involved in the CA, and the CA inhibits PT of subsequent muscle ECC contractions in muscles not involved in the CA.

Stylianos S Vasileiou, Nikolaos D Asimakidis, Athanasios Dalamitros et al.

Abstract Vasileiou, SS, Asimakidis, ND, Dalamitros, AA, and Manou, V. Effects of an 8-week in-season explosive power training program on neuromuscular performance and lower limb asymmetries in young male soccer players. J Strength Cond Res 38(12): 2121–2128, 2024—This study analyzed the effects of incorporating 8 weeks of twice-weekly explosive power training on neuromuscular performance and lower-limb asymmetries applied to soccer. Thirty-five young male soccer players were randomly assigned to either the experimental group (EXP: n = 18; mean age: 13.7 ± 0.8 years; height: 166.9 ± 8.4 cm; body mass: 58.5 ± 12.8 kg) or the control group (CON: n = 17; mean age: 13.7 ± 0.9 years; height: 168.8 ± 9.1 cm; body mass: 58.0 ± 11.4 kg). Before (TP1) and after the training period (TP2) neuromuscular performance (countermovement jump [CMJ], 10 and 20 m sprint times [T10 and T20], change of direction ability [COD]) and lower-limb asymmetries (single-leg CMJ [SLCMJ]) were evaluated. The asymmetry index (AI) for COD and CMJ tests was also calculated. Significant differences (from TP1 to TP2) were revealed for all the tested parameters in the EXP group (1.50–4.9%, p < 0.00 to 0.12, effect size [ES] = −0.44 to 0.27). For the CON group, T10, T20 505 for nondominant limb and SLCMJ performances for both limbs were significantly improved (0.85 to 1.5%, p < 0.00 to 0.21, ES = −0.36 to 0.37). Finally, the AI remained relatively unchanged for both tests and groups (1.28–3.33%, p = 0.162–0.521). These results indicate that adding twice-weekly explosive power training for 8 weeks can improve neuromuscular performance and reduce lower-limb asymmetries to a greater degree than soccer training alone in young male soccer players.

Enrique Fraga-Germade, E. Carballeira, E. Iglesias-Soler

Abstract Fraga-Germade, E, Carballeira, E, and Iglesias-Soler, E. Effect of resistance training programs with equated power on older adults' functionality and strength: a randomized controlled trial. J Strength Cond Res 38(1): 153–163, 2024—This study aimed to compare the effect of 2 training programs of equated power but differing in load intensity on older adults' functionality, strength, performance, and body composition. Forty-four active (23 female) older adults (66.3 ± 4.5 years) were randomly assigned to low-load high-velocity (LL-HV), high-load low-velocity (HL-LV), and control (CON) groups. Low-load high-velocity and HL-LV performed, twice weekly for 5 weeks, a resistance training program at 95% of their individual peak power (PP) but with different load intensities for 3 exercises: chest press (CHP), leg press (LP), and seated row (SR). Before and after the intervention, body composition, functional performance, maximal voluntary isokinetic force (MVF), PP, and a relative load-power profile (L-PP) were evaluated for every exercise. PP similarly improved in the experimental groups for SR and LP (p < 0.05). Both groups increased their MVF for the 3 exercises (p < 0.05). Positive effects on L-PP were observed in LL-HV for SR (p = 0.009) and HL-LV for LP (p < 0.001). CON decreased its global power performance in SR (p = 0.009) and CHP (p = 0.031) compared with the baseline. Both experimental groups improved Timed Up and Go performance (p < 0.05), but only HL-LV increased 6-minute walking performance (pre: 514.3 ± 89.0 m, post: 552.6 ± 65.4 m; p < 0.05). In conclusion, adding short-term power training (i.e., 10 sessions throughout 5 weeks) with loads slightly above the optimal load to nonsupervised multicomponent training might improve active older adults' functional performance and cardiovascular endurance.

Peter W. Harrison, L. James, David G. Jenkins et al.

Abstract Harrison, PW, James, LP, Jenkins, DG, McGuigan, MR, Holmberg, PM, and Kelly, VG. The effects of low-load squat jump and maximal isometric priming exercise on muscular performance and perceptual state. J Strength Cond Res 38(1): 1–9, 2024—The aim of this study was to examine responses at 3 and 27 hours after low-load jump squat (LL) and maximal isometric half-squat (ISO) priming stimuli. Fifteen resistance-trained males performed LL (4 × 3 at 20% 1 repetition maximum [1RM]), ISO (4 × 3 seconds), and control (CON) activities (standardized warm-up) in a randomized and counterbalanced order. Countermovement jump (CMJ) and isometric midthigh pull tests were conducted to assess performance changes after priming and CON activities. No clear changes in CMJ measures were found after priming activities compared with CON. However, small effect size improvements were found after priming stimuli completed on the same day. A 2.9% decrease in concentric phase duration (CI = 0.3–5.9, p = 0.333, Cliff's delta = −0.156) and a 9.1% increase in RSImod (CI = 0.2–12.3, p = 0.151, Cliff's delta = −0.218) occurred at 3 hours after LL compared with CON. Braking phase duration (CI = 0.8–10.6, p = 0.333, Cliff's delta = −0.213) was 2.9% shorter at 3 hours after ISO compared with CON. No clear changes in isometric peak force occurred after priming activities compared with CON. Additionally, questionnaires were completed to assess perceptual state and perceived effectiveness of the priming stimulus to influence performance. An increase in the “effect of activity” was perceived at 3 hours after LL and ISO (p = 0.013–0.044, Cliff's delta = 0.578–0.6) and at 27 hours after ISO (p = 0.99, Cliff's delta = 0.173) compared with CON. An increase in “muscular heaviness” was also reported at 3 hours after ISO compared with CON (p = 0.199, Cliff's delta = 0.320). The collective findings suggest limited benefits over the day after LL and ISO priming stimuli. However, as there was substantial variation in individual responses, the relative nature of priming responses should be considered when prescribing similar strategies in practical environments.

Tony R. Montgomery, Alex A. Olmos, Kylie N. Sears et al.

Abstract Montgomery, TR Jr, Olmos, A, Sears, KN, Succi, PJ, Hammer, SM, Bergstrom, HC, Hill, EC, Trevino, MA, and Dinyer-McNeely, TK. Influence of blood flow restriction on neuromuscular function and fatigue during forearm flexion in men. J Strength Cond Res 38(7): e349–e358, 2024—To determine the effects of blood flow restriction (BFR) on the mean firing rate (MFR) and motor unit action potential amplitude (MUAPAMP) vs. recruitment threshold (RT) relationships during fatiguing isometric elbow flexions. Ten men (24.5 ± 4.0 years) performed isometric trapezoidal contractions at 50% maximum voluntary contraction to task failure with or without BFR, on 2 separate days. For BFR, a cuff was inflated to 60% of the pressure required for full brachial artery occlusion at rest. During both visits, surface electromyography was recorded from the biceps brachii of the dominant limb and the signal was decomposed. A paired-samples t test was used to determine the number of repetitions completed between BFR and CON. ANOVAs (repetition [first, last] × condition [BFR, CON]) were used to determine differences in MFR vs. RT and MUAPAMP vs. RT relationships. Subjects completed more repetitions during CON (12 ± 4) than BFR (9 ± 2; p = 0.012). There was no significant interaction (p > 0.05) between the slopes and y-intercepts during the repetition × condition interaction for MUAPAMP vs. MFR. However, there was a main effect of repetition for the slopes of the MUAPAMP vs. RT (p = 0.041) but not the y-intercept (p = 0.964). Post hoc analysis (collapsed across condition) indicated that the slopes of the MUAPAMP vs. RT during the first repetition was less than the last repetition (first: 0.022 ± 0.003 mv/%MVC; last: 0.028 ± 0.004 mv/%MVC; p = 0.041). Blood flow restriction resulted in the same amount of higher threshold MU recruitment in approximately 75% of the repetitions. Furthermore, there was no change in MFR for either condition, even when taken to task failure. Thus, BFR training may create similar MU responses with less total work completed than training without BFR.

V. G. Corrêa Neto, Danrley do Nascimento Silva, Alexandre Palma et al.

Abstract Corrêa Neto, VG, Silva, DdN, Palma, A, de Oliveira, F, Vingren, JL, Marchetti, PH, da Silva Novaes, J, and Monteiro, ER. Comparison between traditional and alternated resistance exercises on blood pressure, acute neuromuscular responses, and rating of perceived exertion in recreationally resistance-trained men. J Strength Cond Res 38(5): e211–e218, 2024—The purpose of this study was to compare the acute effects of traditional and alternated resistance exercises on acute neuromuscular responses (maximum repetition performance, fatigue index, and volume load), rating of perceived exertion (RPE), and blood pressure (BP) in resistance-trained men. Fifteen recreationally resistance-trained men (age: 26.40 ± 4.15 years; height: 173 ± 5 cm, and total body mass: 78.12 ± 13.06 kg) were recruited and performed all 3 experimental conditions in a randomized order: (a) control (CON), (b) traditional (TRT), and (c) alternated (ART). Both conditions (TRT and ART) consisted of 5 sets of bilateral bench press, articulated bench press, back squat, and Smith back squat exercises at 80% 1RM until concentric muscular failure. The total number of repetitions performed across sets in the bench press followed a similar pattern for TRT and ART, with significant reductions between sets 3, 4, and 5 compared with set 1 (p < 0.05). There was a significant difference for set 4 between conditions with a lower number of repetitions performed in the TRT. The volume load was significantly higher for ART when compared with TRT. TRT showed significant reductions in BP after 10-, 40-, and 60-minute postexercise and when compared with CON after 40- and 60-minute postexercise. However, the effect size illustrated large reductions in systolic BP during recovery in both methods. Thus, it is concluded that both methods reduced postexercise BP.

S. Ketelhut, K. Ketelhut, Sebastian R Ketelhut et al.

Abstract Ketelhut, S, Ketelhut, K, Ketelhut, SR, and Ketelhut, RG. Effects of school-based high-intensity interval training on hemodynamic parameters and heart rate variability: A randomized controlled trial. J Strength Cond Res 38(6): 1033–1040, 2024—The purpose of this study was to assess the effects of a child-specific school-based high-intensity interval training (HIIT) implemented into physical education (PE) classes on various hemodynamic parameters and heart rate variability indices. Forty-six students (age 11 ± 1 year) were randomized into an intervention (INT n = 22) and a control group (CON n = 24). During a 12-week period, the INT and CON groups participated in regular PE twice weekly (45–90 minutes). The INT group received HIIT during the first 20 minutes of the 2 PE classes. Systolic and diastolic blood pressure, total peripheral resistance, aortic pulse wave velocity (aPWV), heart rate, SD of normal to normal heartbeat intervals, the root mean square of successive differences between normal heartbeats (RMSSD), the proportion of differences between adjacent normal to normal heartbeat intervals of more than 50 ms, low-frequency power, high-frequency power, and the LF/HF ratio were assessed before and after the experimental period. A p value ≤0.05 was considered statistically significant. Forty students (20 INT; 20 CON) were included in the analysis. A significant time × group interaction was detected for aPWV (p = 0.05, η2 = 0.099), RMSSD (p = 0.010, η2 = 0.161), low-frequency power (p = 0.009, η2 = 0.165), high-frequency power (p < 0.001, η2 = 0.272), and the LF/HF ratio (p < 0.001, η2 = 0.354). The INT group revealed significant improvements for the respective parameters. School-based HIIT can induce improvements in cardiovascular parameters. These results highlight the potential of embedding HIIT within the school setting, offering a time-efficient exercise intervention.

Ciaran O' Connor, Martin Mc Intyre, E. Delahunt et al.

Abstract O' Connor, C, Mc Intyre, M, Delahunt, E, and Thorborg, K. Maximum isometric hip adduction squeeze and abduction press strength values in men’s rugby union players at select timepoints throughout a competitive season. J Strength Cond Res 39(4): e569–e580, 2025—The purpose of this research was to report hip adduction and abduction strength values in men's rugby union players at select timepoints throughout a competitive season and to examine if differences exist between time of season and hip-testing positions. This cross-sectional repeated measures study design consisted of 15 male rugby union players competing at senior club level. Maximum isometric hip adduction and abduction strength were measured using a ForceFrame in 3 testing positions at specific timepoints: start of preseason (T1), start of competitive season (T2), mid-season period 1 (T3), and mid-season period 2 (T4). At group level, hip adduction strength (N·kg−1) increased from T1 to T2 in all testing positions, with significant increases observed in the 0° hip-flexion short-lever position (p = 0.048), and 45° hip-flexion position (p = 0.032). No significant changes occurred in hip abduction strength (N·kg−1). Hip adduction:abduction strength ratio increased from T1 to T2, with a significant increase observed in the 0° hip-flexion short-lever position (p = 0.008). At individual level, large variations from baseline strength (N·kg−1) were observed between timepoints for hip adduction strength, abduction strength, and adduction:abduction strength ratio. In conclusion, the present study shows increases in hip adduction strength and hip adduction:abduction strength ratio from the start of preseason to the beginning of the competitive season, with no other significant changes in hip strength observed throughout the season. Individual and frequent hip strength monitoring throughout the season and a more individualized exercise prescription approach may be needed for rugby union players, in addition to a more generalized focus on improving adductor and abductor strength.

Sylvia Moeskops, Jon L. Oliver, John M Radnor et al.

Supplemental Digital Content is Available in the Text. Abstract Moeskops, S, Oliver, JL, Radnor, JM, Haff, GG, Myer, GD, Ramachandran, AK, Kember, LS, Pedley, JS, and Lloyd, RS. Effects of neuromuscular training on muscle architecture, isometric force production, and stretch-shortening cycle function in trained young female gymnasts. J Strength Cond Res 38(9): 1640–1650, 2024—This study evaluated the effects of a 10-month neuromuscular training (NMT) intervention on muscle architecture, isometric force production, and stretch-shortening cycle (SSC) function. Thirty-seven girls aged 6–12 years were placed into gymnastics + NMT (gNMT; n = 15), gymnastics only (GYM; n = 10), or maturity-matched control (CON; n = 12) groups. The gNMT group followed a 10-month NMT program in addition to gymnastics training, whereas the GYM group only participated in gymnastics training. Isometric midthigh pull (IMTP) and drop jump (DJ) kinetics were measured, in addition to muscle thickness, fascicle length, and pennation angle of the gastrocnemius medialis at baseline and at 4, 7, and 10 months. A 3 × 4 (group × time) repeated-measures ANCOVA (covariate, % predicted adult height) was used to evaluate within-group changes. Significance level was set at p < 0.05. Significant interaction effects were observed in muscle thickness, absolute (PFabs) and relative peak force (PFrel) in the IMTP and various DJ variables. The gNMT group demonstrated improvements in muscle thickness, IMTP PFabs and PFrel, and DJ kinetics, most commonly evidenced from 7 months onward. The GYM group's muscle thickness also significantly improved, accompanied by improvements in some DJ kinetics. The CON group did not experience any desirable changes. Overall, NMT elicited positive changes in muscle thickness, PFabs and PFrel, and SSC function to a greater extent than gymnastics training alone or growth and maturation. As most adaptations took 7 months, longer-term NMT programs should be implemented with youth female gymnasts.

Courtney E. Wheelock, J. Stooks, J. Schwob et al.

Abstract Wheelock, CE, Stooks, J, Schwob, J, Hess, HW, Pryor, RR, and Hostler, D. Partial and complete fluid replacement maintains exercise performance in a warm environment following prolonged cold-water immersion. J Strength Cond Res 38(2): 290–296, 2024—Special warfare operators may be exposed to prolonged immersion before beginning a land-based mission. This immersion will result in substantial hypohydration because of diuresis. This study tested the hypothesis that both partial and full postimmersion rehydration would maintain performance during exercise in the heat. Seven men (23 ± 2 years; V̇o2max: 50.8 ± 5.3 ml·kg−1·min−1) completed a control trial (CON) without prior immersion and 3 immersion (18.0°C) trials without rehydration (NO) or with partial (HALF) or full (FULL) rehydration. After immersion, subjects completed a 60-minute weighted ruck march (20.4 kg; 5.6 kph) and a 15-minute intermittent exercise protocol (iEPT) in a warm environment (30.0°C and 50.0% relative humidity). The primary outcome was distance (km) covered during the iEPT. A priori statistical significance was set to p ≤ 0.05. Immersion resulted in 2.3 ± 0.4% loss of body mass in all immersion trials (p < 0.01). Distance covered during the first 13-minute interval run portion of iEPT was reduced in the NO rehydration trial (1.59 ± 0.18 km) compared with all other conditions (CON: 1.88 ± 0.18 km, p = 0.03; HALF: 1.80 ± 0.18 km, p < 0.01; FULL: 1.86 ± 0.28 km, p = 0.01). During the final 2 minutes of the iEPT, distance in the NO rehydration trial (0.31 ± 0.07 km) was reduced compared with the FULL rehydration trial (0.37 ± 0.07 km; p < 0.01) but not compared with CON (0.35 ± 0.07 km; p = 0.09) or HALF (0.35 ± 0.07 km; p = 0.08). Both partial and full postimmersion fluid replacement maintained intermittent exercise performance and should be applied as rehydration strategies.

Gabriel Fontanetti, R. V. Barreto, R. C. Junior et al.

Abstract Fontanetti, G, Barreto, RV, Junior, RC, Marangoni, V, Denadai, BS, Greco, CC, and Lima, LCR. The use of the self-selected rest interval method is as effective for optimizing postactivation performance enhancement in elite athletes as employing the best fixed rest interval. J Strength Cond Res 39(1): 10–15, 2025—This study investigated whether the adoption of a self-selected recovery interval (SSI) is more effective than the use of a fixed recovery interval (FRI) to elicit postactivation performance enhancement (PAPE). Ten male professional volleyball athletes (20.6 ± 1.5 years; 92.8 ± 4.9 kg; 195 ± 8 cm) participated in 3 experimental sessions, in random order, following familiarization with countermovement jump (CMJ) exercises and determination of the load for 5-repetition maximum (5RM: 146 ± 27 kg) squat exercise. The 3 experimental sessions consisted of (a) control session (CON), with measurement of CMJ height 4 minutes before and 2, 4, 6, 8, and 10 minutes after subjects rested while sitting in a chair without performing any preactivation (PA) protocol; (b) session with FRI, with measurement of CMJ height 2, 4, 6, 8, and 10 minutes after performing a PA exercise consisting of 5 squats with 5RM load; and (c) session with SSI, with evaluation of CMJ height once after performing the PA adopting a SSI based on a readiness scale. No significant differences were found between CMJ height in the CON session. Countermovement jump height was higher (p < 0.05) than the baseline measurement at minutes 4, 6, and 8 post-PA in the FRI session, for the best CMJ performance during the FRI session, and after the PA in the SSI session. No significant differences were found between the heights of the best CMJ in the FRI session (49.2 ± 6.8 cm) and post-PA in the SSI session (49.6 ± 6.6 cm). Therefore, adopting FRI and SSI is equally effective in eliciting PAPE in elite athletes. Despite being as effective as adopting FRI to elicit PAPE, SSI is more intuitive and easily applicable in contexts where PAPE can be implemented.

Rodrigo Ramirez-Campillo, C. Álvarez, F. García-Pinillos et al.

Ramirez-Campillo, R, Álvarez, C, García-Pinillos, F, García-Ramos, A, Loturco, I, Chaabene, H, and Granacher, U. Effects of combined surfaces vs. single-surface plyometric training on soccer players' physical fitness. J Strength Cond Res XX(X): 000-000, 2018-The aim of this study was to compare the effects of a 8-week plyometric jump training (PJT) performed on different surfaces (grass, land-dirt, sand, wood, gym mat, and tartan-track) vs. a single-surface PJT (grass) on components of physical fitness (muscle power, speed, and change-of-direction speed [CODS] tasks) and sport-specific performance (i.e., maximal kicking velocity [MKV]) in male soccer players aged 11-14 years. Athletes were randomly assigned to a combined surfaces PJT (PJTc, n = 8), a single-surface PJT (PJTs, n = 8), or an active control (CON, n = 7). Although the PJT group trained on grass, the PJTc trained on 6 different surfaces and equally distributed the total jump volume according to the surface. Pre-post tests were conducted on grass. Significant main effects of time were observed for the countermovement jump, the standing-long-jump, the 20-cm drop jump, 30-m sprint time, CODS, and MKV (all p 0.05; d = 0.07-0.1). In conclusion, PJT is effective in improving physical fitness in young soccer players when conducted in combination with regular soccer training. Although general fitness testing and PJTs were performed on grass, larger physical fitness improvements were found after PJTc. Thus, PJTc is recommended, as it provides a better overload stimulus compared with more conventional training overload (e.g., increase in training volume or intensity). Future studies still have to address the underlying physiological adaptations after PJTc.