Acute effect of different types of upper body maximal conditioning contractions on postactivation potentiation
University of Wales Institute Cardiff
MetadataDangos cofnod eitem llawn
The purpose of the current study was to validate the use of prior high resistance exercise (HRE) on subsequent muscular power exercises improvement. The study aims to examine the postactivation potentiation (PAP) effect produced by isometric (ISO), concentric (CON), eccentric (ECC) or concentric-eccentric dynamic (DYN) conditioning contractions in the bench press exercise upon subsequent neuromuscular activation, force, and power performance of the upper limbs during a ballistic bench throw exercise (BBT). Test variables measured were peak power output (PPO), peak force (F), peak distance (D), maximum rate of force development (max. RFD), maximum electromyography values (MEMG) and integrated average electromyography (AEMG). PAP is an increase in muscle isometric twitch and low frequency titanic force following a "conditioning" activity which has been shown to improve muscular performance in speed and power activities. The theory of PAP suggests that prior high resistance exercise (HRE) induces a high degree of neural stimulation that results in an increased number of motor unit recruitment and a higher-frequency rate coding for several minutes following HRE. If this principle is correct, the test interventions will provide maximal stimulus for neuromuscular adaptations, thus increasing power output, providing support for the theory of complex training. Complex training is a recently advanced power training method characterized by a dynamic heavy-load exercise proceeded by a biomechanically similar plyometric exercise. 10 male amateur rugby league players of age; 20.4 (±0.8) years, weight; 90.2 (±13.8) kg and stature; 176.95 (±8.1) cm, and with at least one years' resistance training history (2.19 ± 0.9 years), performed a BBT; pre (P1), and post (P2) a set of CON, ECC, ISO or DYN 3RM bench press‟ on each testing day. P1 and P2 were performed on a smith machine, using a ballistic measurement system (BMS) to determine to determine the test variables, and neuromuscular activation characteristics were measured in the pectoralis major (PM) and triceps brachii (TB) using electromyography (EMG). The EMG data was analysed for maximum EMG (MEMG) and average EMG (AEMG). A change in either measure was determined as a change in motor unit recruitment and/or firing rate. Results found a significant increase (p<0.05) in PPO during P2, following ISO preconditioning. No significance was found in PPO following CON, ECC or DYN interventions, F, D or max RFD for either of the preconditioning interventions. Moreover, no significance in MEMG or AEMG was found between P1 and P2 following any of the preconditioning contractions. However, a positive trend (p=0.052) was found in AEMG following ISO preconditioning. In conclusion; a 7 second ISO preconditioning contraction may offer a simple exercise that induces a potentiated neuromuscular environment conductive to enhanced performance during explosive dynamic powerful movements. The complex treatment did not enhance performance in BBT following CON, ECC and DYN interventions. However, neither was it found to have a detrimental effect on performance, and therefore may have organisational benefits in an athletes' high volume training programme. For reliable results regarding the effectiveness of complex training a longitudinal training study needs to be investigated against other power training methods.
Yn dangos eitemau sy’n perthyn drwy deitl, awdur, pwnc a chrynodeb.
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