Joseph I. Esformes

The physical demands of competitive match-play in elite soccer have increased continuously in recent years (Morgans et al. 2024) with high-speed running and sprint distance rising across recent Eng...

Houlton, LJ, Moody, JA, Bampouras, TM, and Esformes, JI. Acute effect of intracontrast rest redistribution within complex-contrast training set strategies on vertical jump propulsive force. J Strength Cond Res XX(X): 000–000, 2026—Complex-contrast training (CCT), whereby high-load conditioning activities (CA) and low load explosive activities are alternated set-by-set, enhances explosive performance through postactivation performance enhancement (PAPE). However, intracontrast rest periods (ICRP) typically required for PAPE to manifest are too lengthy in practice. This study, therefore, assessed the effect of rest redistribution (RR) of the ICRP on subsequent propulsive force application during countermovement jumps and squat jumps. Seventeen male subjects completed 5 interventions per jump type across 5 data collection sessions in a counterbalanced, cross-sectional design. Interventions consisted of 5 total contrast rest periods (TCRP; 60, 120, 180, 240, 300 seconds). Each TCRP was defined as the sum of ICRP and RR. Thus TCRPs were partitioned as 30, 90, 150, 210, 270 seconds ICRP respectively, and 30 seconds of redistributed rest, partitioned between CA repetitions. Within interventions, subjects performed a control condition consisting of 1 set of vertical jumps (BASELINE), the assigned ICRP, then a second set of jumps (PRE-BS). This was followed by an experimental condition consisting of a high-load CA (3-repetition maximum back squats), performed with 15 seconds between repetitions, followed by the ICRP, then a final set of jumps (POST-BS). Vertical jump propulsive impulse (J _PROP ) and related force–time components were assessed. Results showed no meaningful change in J _PROP , suggesting overall jump performance was unaffected. However, increases in propulsion time, with POST-BS being higher than PRE-BS ( g = 1.045, p < 0.001), and significant negative effects on rate of force development with POST-BS being lower than PRE-BS ( g = 0.703, p = 0.009), suggest the combination of CCT and RR may negatively affect vertical jump propulsion strategies and limit PAPE manifestation. Practitioners may use RR to maintain vertical jump J _PROP within CCT in time-limited scenarios, but should consider other CCT set configurations to enhance rate of force development.

This study aimed to evaluate the performance expression stability (PES) of sixteen alternative complex–contrast training (CCT) set strategies. Three separate cross-sectional studies (n = 14–17) evaluated the effects of different intra-contrast rest periods (ICRP; ≤300 s) and rest redistribution (RR) strategies (≤60 s) within CCT sets on the application of vertical jump propulsive force were examined using dual force platforms. To establish PES for propulsive force–time variables, repetitions one and two of the baseline set were analyzed using within-participant (coefficient of variation, CV; standard error of measurement; smallest worthwhile change; relative mean bias) and between-participant (intra-class correlation coefficient, ICC_3,1; Pearson’s correlation coefficient, r) stability metrics. Results showed that all CCT set strategies facilitate stable performance expression between participants and facilitated the detection of practically meaningful changes for propulsive impulse, peak force, mean force, and propulsion time (ICC_3,1 = 0.64–0.99, r = 0.80–0.99, CV = 1.12–9.98%), while rate of force development metrics demonstrated less consistent between- and within-participant stability (ICC_3,1 = 0.55–0.97, r = 0.46–0.96, CV = 7.52–27.66%). The findings indicate that alternative CCT set strategies facilitate the stable expression of propulsive force–time performance in vertical jumps, although individualized prescriptions are essential for optimizing rate of force development outcomes. Performance expression stability insights provide a practical tool for balancing the effectiveness and potential for performance enhancement of vertical jump propulsion across alternative CCT set strategies. Practitioners may use these results to improve the prescription and monitoring of CCT-based strength and power mesocycles.

Complex-contrast training (CCT) is an advanced training method that aims to augment explosive force application through post-activation performance enhancement (PAPE). However, the intra-contrast rest periods (ICRP) required to observe PAPE are typically 5-12 minutes, making CCT impractical for most training scenarios. This study, therefore, aimed to assess whether combining CCT sets with rest redistribution (RR) strategies could reduce the total contrast rest period (TCRP) required to observe PAPE in vertical jump metrics. 15 male subjects completed 10 experimental interventions across 5 data collection sessions in a counterbalanced cross-sectional design. Interventions consisted of 2 vertical jump variations (countermovement jump (CMJ) and squat jump (SJ)) and 5 TCRPs (TCRP; 60, 120, 180, 240, 300 s), partitioned as 0, 60, 120, 180, 240 s ICRP, respectively, and 60 s of RR. Within interventions, participants performed a control condition consisting of 1 set of vertical jumps (BASELINE), the assigned ICRP, then a second set of jumps (PRE-BS). This was followed by an experimental condition consisting of 3RM back squats with 30 s between repetitions, then the ICRP, and a final set of jumps (POST-BS). Vertical jump propulsive impulse (JPROP) and related force-time components were assessed. A 5x2x2 (TCRP*CONDITION*TIME) repeated measures ANOVA assessed differences in force-time variables. Results showed no significant interaction of TCRP*CONDITION*TIME for JPROP, indicating that, regardless of intervention, neither CMJ nor SJ JPROP was enhanced. However, RR led to significant increases in both peak and average CMJ rate of force development (RFD) and reduced propulsion time (tPROP) after TCRP180, TCRP240, and TCRP300, demonstrating a more explosive, but not higher, jump. For SJ, no meaningful changes in RFD or tPROP were observed. Thus, RR may preserve JPROP while augmenting explosive force application via enhanced eccentric-concentric coupling and stretch-shortening cycle efficiency, but PAPE remains insufficient to increase jump height in recreationally strong populations. Practically, RR may reduce the time required within CCT sets to observe PAPE through enhanced RFD. This combined approach may also be an effective tool for increasing training density by maintaining explosive capacity during power phases without impairing performance. However, longer rest may still be necessary when maximising impulse is the primary goal.

Background: Cluster sets (CSs) maintain velocity and power in compound movements by employing similar propulsion strategies or maintaining impulse through different mechanisms. This study aimed to explore the effect of four CS conditions on back squat (BS) propulsion and provide models for estimating changes in propulsion based on repetition and set number. Methods: Twenty male participants (age = 28.3 ± 3.1 years, stature = 1.74 ± 8.21 m, body mass = 84.80 ± 7.80 kg, BS 1RM = 140.90 ± 24.20 kg) completed four data collection sessions. Each session consisted of three sets of five repetitions at 80% 1RM BS with three minutes of unloaded inter-set rest, using varying intra-set rest intervals. Experimental conditions included 0 s (TRAD), 10 s (CS10), 20 s (CS20), and 30 s (CS30) inter-repetition rest, randomly assigned to sessions in a counterbalanced order. Ground reaction force data were collected on dual force platforms sampling at 1000 Hz, from which net propulsive impulse (J_PROP), mean force (MF), and propulsion time (t_PROP) were calculated. Conditions and sets were analysed using a 4 × 3 (CONDITION*SET) repeated-measures ANOVA to assess differences between conditions and sets, and linear mixed models (LMMs) were used to provide regression equations for each dependent variable in each condition. Results: The ANOVA revealed no significant interactions for any dependent variable. No main effects of CONDITION or SET were observed for J_PROP. The main effects of CONDITION showed that MF was significantly lower in TRAD than CS20 (g = 0.757) and CS30 (g = 0.749). t_PROP was significantly higher in TRAD than CS20 (g = 0.437) and CS30 (g = 0.569). The main effects of SET showed that MF was significantly lower in S2 (g = 0.691) and S3 (g = 1.087) compared to S1. t_PROP was significantly higher in S2 (g = 0.866) and S3 (g = 1.179) compared to S1. LMMs for CS20 and CS30 revealed no significant effect (p > 0.05) between repetition or set number and dependent variables. Conclusions: The results suggest that CS20 and CS30 maintain J_PROP by limiting MF and t_PROP attenuation. This is less rest than that suggested by the previous literature, which may influence programming decisions during strength and power mesocycles to maximise training time and training density. LMMs provide accurate estimates of BS propulsive force attenuation when separating repetitions by up to 30 s, which may help practitioners optimise training load for long-term adaptations.

This systematic review and meta-analysis was conducted to evaluate the effectiveness of the FIFA 11+ injury prevention programme, a neuromuscular training intervention involving muscular strength, proprioception, balance, and plyometric exercises, in reducing ankle injury incidence among football players. Included are randomised controlled trials (RCTs) involving players of any age, sex, or competition level, comparing the FIFA 11+ programme with standard warm-up routines. Studies were eligible if they had a minimum follow-up of five months and reported at least two of the following: number of ankle injuries, incidence rate, and exposure hours. Searches were conducted in PubMed, MEDLINE (via OVID), Scopus, and SPORTDiscus up to October 2024. Risk of bias was assessed using the revised Cochrane Risk of Bias tool (RoB 2), and a random-effects meta-analysis was conducted. Three RCTs, involving 3833 participants and 286,827 exposure hours, met the inclusion criteria. The pooled analysis showed that the FIFA 11+ programme significantly reduced ankle injury rates compared to control groups (rate ratio (RR) = 0.67, 95% confidence interval (CI): 0.46–0.96, p = 0.03, I² = 52%), reflecting a 33% lower risk. The certainty of the evidence was rated as moderate due to bias in two studies. In conclusion, the FIFA 11+ programme significantly reduces ankle injury incidence and supports implementation at all levels. However, further research is needed to examine long-term effects, optimal doses, and applicability across diverse football populations.

Purpose: The purpose of this study was to examine the effects of resistance training (RT) in physical education lessons on athletic motor skill competencies in secondary school children. Method: Seventy-eight males were randomized into experimental year groups or a control group. Experimental groups participated in RT during physical education lessons for a 6-week half-term. The control group continued with their games-based curriculum. Countermovement jump (CMJ) height, seated medicine ball throw (SMBT) distance, and RT skills battery scores were measured preintervention and postintervention. Results: All experimental groups significantly improved SMBT distance and RT skills quotient (P < .05). All intervention year groups also significantly improved CMJ height (P < .05), except for year 9. Although the control group did not show improvements in CMJ height and RT skills quotient, there was a significant improvement in SMBT distance (P < .05). The year 7 and 8 males exhibited greater improvements in CMJ height and SMBT distance (d = 0.21–0.79) than in year 9 (d = 0.00–0.40). Conclusion: Results of the study indicated that a 6-week half-term RT intervention in physical education lessons can improve athletic motor skill competencies (P < .05, d = 0.21–2.51) in male youths.

This study aimed to explore collegiate student-athletesˈ preferences of coaching leadership behaviours in strength and conditioning coaching and evaluate differences between the student-athletesˈ preferences of behaviours based on task variability. In total 145 National Collegiate Athletic Association student-athletes (closed sports athletes = 51, open sports athletes = 94) completed an electronic questionnaire involving the athletesˈ preference version of the Revised Leadership Scale for Strength and Conditioning. Results revealed that the most favoured behaviour was ˈtraining and instructionˈ, whilst the least favoured was ˈautocraticˈ. Similar results were observed for closed and open sports groups, though closed sports athletes preferred ˈtraining and instructionˈ. In contrast, open sports athletes preferred ˈsocial supportˈ. A marginal statistically significant difference (p = 0.048) indicated task-variability-based variations that might form a fruitful basis for future research. However, small effect sizes suggest that the magnitude of differences is not practically significant. This study provides insights on collegiate student-athletesˈ preferences of coaching leadership behaviours in delivery of strength and conditioning, contributing to the development and experiences of athletes. Both groups valued positive psychosocial behaviours such as training and instruction, positive feedback, situational considerations and social support. The findings offer implications for coaching and provide a foundation for further research into coaching leadership behaviours in strength and conditioning.

The study investigated athletes’ preferred coaching leadership behaviours in strength and conditioning coaching at a British University, integrating quantitative and qualitative data to evaluate the confirmation or divergence of results. Athletes' preferences were explored to offer novel perspectives in this area. A convergent mixed methods design with parallel databases was implemented, using quantitative data through an electronic questionnaire using the athletesˈ preference version of the Revised Leadership Scale for Strength and Conditioning and qualitative data through semi-structured interviews based on the constructs of that scale. A total of 49 male and female British university athletes completed the questionnaire, and 13 participated in follow-up interviews. The qualitative purposeful sample was a subset of the convenience quantitative sample. The mixed-methods findings are the meta-inferences drawn by comparing the matched quantitative and qualitative findings across six behavioural dimensions: autocratic, democratic, positive feedback, situational consideration, social support, and training and instruction behaviours. The survey results illustrate the preferences of behaviours, and the qualitative findings confirmed and further expanded the survey results. Athletes appreciate a mix of autocratic and democratic behaviours, valuing authority when necessary but predominantly collaboration, especially in goal-setting. Positive feedback and instructions are highly valued when genuine, contextually appropriate, and provided during significant efforts, such as when lifting heavy weights or learning new techniques. Athletes appreciate coaches who maintain professional boundaries whilst showing empathy, strong social interaction skills, and the capacity to consider situational factors to set achievable goals. An integrated mixed-methods analysis highlights how behaviours cannot be evaluated independently of context and that strength and conditioning coaches should exhibit adaptability and a genuine interest in developing personal connections. These findings offer a basis for further research to expand the investigation of coaching leadership behaviours in strength and conditioning coaching.

Background: Previous work has found that combining plyometric and resistance training in a single session can be effective in improving maximum strength (muscle contraction ability), vertical jumping, and sprint acceleration performance in young soccer players. However, the literature is scarce in relation to young rugby union players. Thus, the purposes of the present study were to examine the effects of a 6-week combined training (CT) programme that combined plyometric and resistance training in the same session on physical performance measures in adolescent male rugby union players and whether a 4-week period of plyometric training exclusion (Detraining) affects training adaptations. Methods: The participants (n = 15) completed a 6-week CT intervention and 4 weeks of plyometric detraining during the schoolboy rugby union in-season. A performance testing battery was conducted pre-intervention, post-intervention, and 4 weeks post-intervention. Results: A repeated measures ANOVA showed a significant effect for time on CMJ variables (mean power, mean force, and modified reactive strength index [RSI]), 3RM back squat strength, and 505 test time (p < 0.05). Pairwise comparisons revealed that CMJ variables (mean force, mean power, and peak power), 3RM back squat strength, and 505 test performance significantly increased from pre-intervention to post-intervention (p < 0.05). The 4-week plyometric detraining period significantly augmented CMJ variables (mean force, mean power, and modified RSI) and performance measures (standing broad jump [SBJ], 20 m sprint time, 505 test, and 3RM strength). Conclusions: The findings indicate that a 6-week CT programme can augment measures of lower-body power, maximal strength, and change of direction performance in adolescent male rugby union players, and a 4-week resistance training-only period (plyometric detraining) does not negatively affect performance adaptations.