Search results for "Post activation potentiation"

Postactivation potentiation can counteract declines in force and power that occur after stretching.

2016

Stretching can decrease a muscle's maximal force, whereas short but intense muscle contractions can increase it. We hypothesized that when combined, postactivation potentiation induced by reactive jumps would counteract stretch-induced decrements in drop jump (DJ) performance. Moreover, we measured changes in muscle twitch forces and ankle joint stiffness (KAnkle ) to examine underlying mechanisms. Twenty subjects completed three DJs and 10 electrically evoked muscle twitches of the triceps surae subsequent to four different conditioning activities and control. The conditioning activities were 10 hops, 20s of static stretching of the triceps surae muscle, 20s of stretching followed by 10 ho…

Acute neuromuscular responses to short and long roundhouse kick striking paces in professional Muay Thai fighters.

2019

International audience; BACKGROUND: Muay Thai fighters strongly rely on the use of the roundhouse kick due to its effectiveness (i.e. power) and implications on the final score. Therefore, different striking tempos at full power are used during training as a method to enhance kicking power. However, the neuromuscular responses are unknown. Thus, the goal of this study was to investigate neuromuscular responses to a single bout of shorter (every second = H1) and longer (every 3s = H3) kick striking time intervals, measured with the countermovement jump (CMJ).METHODS: Nine professional Muay Thai fighters participated in this randomized, cross-over trial. CMJs were measured on force plates bef…

Acute Effects of Loaded Half-Squat Jumps on Sprint Running Speed in Track and Field Athletes and Soccer Players

2016

The purpose of the study was to determine the acute responses to a jump squat protocol designed to induce postactivation potentiation on sprint running performance in experienced track and field athletes and soccer players. Twenty-five regional level athletes (12 track and field: ∼17 years; ∼177 cm; ∼73 kg and 13 soccer: ∼18 years; ∼175 cm; ∼72 kg) performed 2 test sessions assessing 40-m sprint running performance in a balanced, crossover design. Dual-beam light timing gates measured 0-20 and 20-40 m sprint times before and after either 9 minutes of sitting (control) or 2 sets of 6 repetition half-squat jump with the load eliciting maximum power (experimental) conditions. Sprint performanc…

2019

Post-activation potentiation (PAP) is a well-described phenomenon with a short half-life (~28 s) that enhances muscle force production at submaximal levels of calcium saturation (i.e., submaximal levels of muscle activation). It has been largely explained by an increased myosin light chain phosphorylation occurring in type II muscle fibers, and its effects have been quantified in humans by measuring muscle twitch force responses to a bout of muscular activity. However, enhancements in (sometimes maximal) voluntary force production detected several minutes after high-intensity muscle contractions are also observed, which are also most prominent in muscles with a high proportion of type II fi…

Unilateral Conditioning Contractions Enhance Power Output in Elite Short Track Speed Skaters

2018

AbstractThe objective of the present study was to assess the effect of unilateral lower-body-conditioning muscle contractions during multiple sets of fatiguing repeated jumps in elite athletes. Five elite short-track speed-skating athletes performed 9 sets of 6 maximal consecutive jumps on 2 separate occasions: with (COND) and without (CTRL) preliminary voluntary conditioning contractions (CC) 5 min before the beginning of the sets. The CC consisted of 2 consecutive 3 s maximal unilateral isometric squats against a fixed bar, resulting in a 6 s overall isometric contraction per leg. For each set, power output (PO) was measured using a linear position transducer and averaged over the 6 corre…

Postactivation potentiation in human knee extensors during dynamic passive movements.

2008

Purpose: Postactivation potentiation (PAP), i.e., the increase in twitch torque following a maximal voluntary conditioning contraction, has been shown to depend on muscle contractile conditions (e.g., muscle length). Few studies, however, have investigated the extent of twitch PAP under dynamic conditions in human subjects. Therefore, the aim of the present experiment was to test the twitch PAP during passive dynamic movements following isometric conditioning contractions on nine healthy men. Methods: Maximal twitches were evoked on the knee extensor muscles before and exactly 5 s after a 3-s conditioning maximal voluntary isometric contraction. PAP was determined at a constant joint angle …

The acute effects of different high-intensity conditioning activities on sprint performance differ between sprinters of different strength and power …

2021

The purpose of the present study was to examine the effect of different conditioning activities (CAs) on short-term increase in sprint performance. In twelve male sprinters (21.1+2.6 years, 100 m performance: 11.5+0.6 s) their body composition, half squat maximum strength, 100 m sprinting and countermovement jump performances were evaluated. The performance of a 50 m sprint (splits at 10 m, 30 m and 50 m) was evaluated before and 5, 10 and 15 min after four postactivation performance enhancement CAs on different occasions: [1] 3 sets x 4 s maximum isometric half squat (IHF), [2] 3 sets x 3 consecutive countermovement jumps (cCMJs), [3] 3 repetitions x 30 m overspeed sprinting (OVSP) and [4]…

Acute neuromuscular and hormonal responses during contrast loading: Effect of 11 weeks of contrast training

2009

The purpose of this study was to assess (1) acute neuromuscular and endocrine responses during a contrast loading protocol and (2) how these acute responses are possibly influenced by 11 weeks of contrast training. Contrast loading tests consisting of 4 sets of 80% 1 RM back squat and 4 sets of squat jump (SJ) were performed before and after training. Bilateral isometric leg extension (LE) assessed the impact of loading on isometric variables pre-, mid-, and post-loading. Potentiated SJ performance was observed in set 2 (4.6%, P<0.05), before training only. Greater indications of fatigue were observed in SJ, isometric force, and vastus lateralis (VL) activation after training (P<0.05). Trai…