The acute effects of plyometric and sled towing stimuli with and without caffeine ingestion on vertical jump performance in professional soccer players

Abstract Background Post-activation potentiation (PAP) is the phenomenon by which muscular performance is enhanced in response to a conditioning stimulus. PAP has typically been evidenced via improved counter movement jump (CMJ) performance. This study examined the effects of PAP, with and without prior caffeine ingestion, on CMJ performance. Methods Twelve male professional soccer players (23 ± 5 years) performed two trials of plyometric exercises and sled towing 60 min after placebo or caffeine ingestion (5 mg.kg− 1) in a randomized, counterbalanced and double-blinded design. CMJ performance was assessed at baseline and 1, 3 and 5 min after the conditioning stimulus (T1, T3 and T5, respectively). Results Two way ANOVA main effects indicated a significant difference in jump height after the PAP protocol (F[3, 11] = 14.99, P  0.05) compared to placebo. Conclusions The results of this study suggest that acute plyometric and sled towing stimuli enhances jump performance and that this potentiation is augmented by caffeine ingestion in male soccer players

Bodyweight squats can induce post-activation performance enhancement on jumping performance: a brief report

Post-activation potentiation enhancement (PAPE) refers to increased force generation following a muscular conditioning pre-activity that acutely enhances subsequent strength and power performance. Athlete apprehension to use heavy weights (i.e. >80%1RM) immediately before a competition or inability to use weights before the performance (e.g. due to regulations) prevent materialising the benefits of PAPE. Therefore, this study examined whether PAPE can be induced with bodyweight squats. Sixteen healthy, team sports players (male: 10, female: 6, mean ± SD: age 22.2 ± 3.0 years, height 1.67 ± 0.08 m, body mass 70.2 ± 8.2 kg) performed three sets of ten repetitions of bodyweight squats with 30 seconds recovery between each set. A countermovement jump was performed 5 minutes before, 2 and 4 minutes after the squat sets and jump height was calculated. The results showed existence of PAPE with the jump height increasing at both 2 (30.8 ± 5.6 cm, p = 0.045, g = 0.21) and 4 (30.8 ± 6.1 cm, p = 0.037, g = 0.20) minutes, compared to baseline (29.5 ± 6.4 cm). This is the first study to use bodyweight squats rather than loaded squats. Our findings indicate that three sets of ten repetitions of squats using bodyweight only can be a sufficient stimulus to induce PAPE

Acute effects of intra-complex rest following back squats on vertical jump performance during complex training

Post-activation performance enhancement and complex-contrast sets are prevalent in sports science research. Typical complex-contrast sets consist of heavy back squats, an intra-contrast rest period (ICRP) and vertical jumps (countermovement jumps [CMJ], or squat jumps [SJ]). Propulsive impulse (Jprop) is considered the leading indicator of jump performance. However, studies evaluating jump performance during complex-contrast sets use jump height as the primary performance measure, limiting insight into ICRP's effect on jump performance. We assessed the effect of a three-repetition maximum (3RM) back squat and six ICRPs on vertical jump Jprop and associated force-time components. Fourteen participants completed 12 experimental conditions, assigned equally to four testing sessions. Independent variables, in a 6x2 randomised, counterbalanced design, were ICRP (0, 60, 120, 180, 240, 300 s; ICRP0, ICRP60, ICRP120, ICRP180, ICRP240, ICRP300, respectively) and vertical jump (CMJ and SJ). Conditions consisted of baseline vertical jumps, followed by three back squat repetitions at 100% 3RM, an ICRP and experimental jumps. Symmetrised percentage changes between experimental and baseline jumps were assessed using repeated measures ANOVA and pairwise effect sizes. Results showed significant effects (p ≤ 0.05) on CMJ average rate of force development (RFD) between ICRP0 and ICRP120 and ICRP0 and ICRP300. Pairwise comparisons showed medium and large effect sizes for and increases in CMJ RFD (g = 0.83-2.69) while SJ RFD decreased (g = 0.81-2.57). Small effect sizes were found for Jprop, peak force and mean force. Results suggest limited change in Jprop (g = 0.01-0.58) but back squats may potentiate RFD via the stretch-shortening cycle