Effekt av verbala instruktioner på muskelaktivitet vid bänkpressträning

[King Grub]

Recent research suggests that humans have some ability to selectively activate or relax some muscles during isometric or dynamic muscle actions without changing posture or position. This study sought to reveal whether trained athletes could isolate either the pectoral or triceps muscles, respectively, at different intensities when given verbal technique instruction. Eleven male Division III football players performed three sets of three of bench press at 50% 1-repetition max (RM) and 80% 1RM while EMG activity was recorded from the pectoralis major (PM), anterior deltoid (AD), and triceps brachii (TB). In the first set, subjects performed the exercise without instruction. In the second set subjects were given verbal instructions to use only chest muscles. In the third set, subjects were instructed to use only triceps muscles. Mean normalized root mean square EMG activity was calculated during three repetitions in each condition. Repeated measures ANOVA was used to detect differences from the pre-instruction condition, with significance set to p≤.017 as indicated by a Bonferroni correction for multiple comparisons. During the 50% max lift with verbal instructions to focus on chest muscles, PM EMG activity increased by 22% over pre-instruction activity (p=.005), while AD and TB activity were statistically unchanged. When subjects were instructed to focus on only the triceps muscles, PM returned to baseline activity while TB activity was increased by 26% (p=.005). When the lift was increased to 80% max, PM and AD activity were both increased with verbal instructions to use only chest muscles. TB activity was unchanged during the 80% lifts, regardless of instructions. In conclusion, verbal technique instruction is effective in shifting muscle activity during a basic lift, but may be less effective at higher intensities.

J Strength Cond Res. 2011 Nov 9. Effect of verbal instruction on muscle activity during the bench press exercise.

[King Grub]

Improved training quality has the potential to enhance training adaptations. Previous research suggests that receiving feedback improves single-effort maximal strength and power tasks, but whether quality of a training session with repeated efforts can be improved remains unclear. The purpose of this investigation was to determine the effects of verbal feedback on upper-body performance in a resistance training session consisting of multiple sets and repetitions in well-trained athletes. Nine elite rugby union athletes were assessed using the bench throw exercise on 4 separate occasions each separated by 7 days. Each athlete completed 2 sessions consisting of 3 sets of 4 repetitions of the bench throw with feedback provided after each repetition and 2 identical sessions where no feedback was provided after each repetition. When feedback was received, there was a small increase of 1.8% (90% confidence limits, ±2.7%) and 1.3% (±0.7%) in mean peak power and velocity when averaged over the 3 sets. When individual sets were compared, there was a tendency toward the improvements in mean peak power being greater in the second and third sets. These results indicate that providing verbal feedback produced acute improvements in upper-body power output of well-trained athletes. The benefits of feedback may be greatest in the latter sets of training and could improve training quality and result in greater long-term adaptation.

J Strength Cond Res. 2011 Nov 10. Acute effects of verbal feedback on upper-body performance in elite athletes.