Changes in Muscle Activation and Force Generation Patterns During Cycling Movements Because of Low-Intensity Squat Training With Slow Movement and Tonic Force Generation

Abstract

Our previous studies showed that relatively low-load (approximately 50-60% 1 repetition maximum [1RM]) resistance training with slow movement and tonic force generation (LST) significantly increased muscle size and strength. However, LST is a very specific movement that differs from natural movements associated with sport activities and activities of daily life, and therefore, it might have some unfavorable effects on dynamic sport movement. We investigated the effects of LST on muscle activity and force generation patterns during cycling movement as a representative dynamic sports movement. Twenty-four healthy young men who were not in the habit of bicycle riding and did not have a history of regular resistance training were randomly assigned to the LST (approximately 60% 1RM load, 3-second lifting, and 3-second lowering movement without a relaxing phase: n = 8), a high-intensity exercise at normal speed (HM) group (85% 1RM load, 1-second lifting, 1-second lowering, and 1-second relaxed movement: n = 8), or sedentary control (CON, n = 8) group. Subjects in the training groups performed vertical squats by the assigned method. Exercise sessions consisted of 3 sets and were performed twice a week for 13 weeks. Pre- and posttraining muscle activation and force generation patterns during the cycling movements were evaluated by the coefficient of variation (CV) of the rectified electromyographic (EMG) wave from the vastus lateralis and CV of pedaling force. Both the CV of the rectified EMG and of pedaling force decreased significantly in the LST group (-21 and -18%, p < 0.05, respectively), whereas there were no significant changes in either the HN or the CON group. This decrease in CV in the LST group could mean that muscle activity and force generation during cycling movement have become more tonic. This result following LST may have an unfavorable effect on cycling movement and other dynamic sports movements.

Low-load Slow Movement Squat Training Increases Muscle Size and Strength but Not Power

“…important neuromuscular function in various physical activities and also contributes to reducing the incidence of falling or slipping, especially in elderly populations [2]. Tanimoto et al [26] also observed that a 13-week LST program in the leg muscles changed muscle activation and force generation patterns during dynamic (cycling) movements to be more tonic. This suggests that LST may have unfavorable effects on dynamic power production, since more instantaneous (i. e., less tonic) muscle activation is important for achieving high power [1], especially during dynamic explosive movements.…”

Effect of resistance training using bodyweight in the elderly: Comparison of resistance exercise movement between slow and normal speed movement

“…Conversely, the LST protocol has an unfavorable effect on dynamic sports movements . Thus, this type of exercise might be ineffective for improving motor function in the activities of daily life of the elderly, such as walking and climbing stairs.…”

“…Conversely, the LST protocol has an unfavorable effect on dynamic sports movements. 21 Thus, this type of exercise might be ineffective for improving motor function in the activities of daily life of the elderly, such as walking and climbing stairs. For comprehensive improvement of physical function, the LST protocol should be combined with exercises that specialize in improving the nervous system, such as plyometric exercise, which improves muscle power and physical performance.…”

Comprehensive geriatric intervention in community‐dwelling older adults: a cluster‐randomized controlled trial

“…Tanimoto et al . reported that the slow movement protocol had a detrimental effect on dynamic sports movements . Therefore, several quickly performed exercises were included in this CGIP .…”

“…Tanimoto et al reported that the slow movement protocol had a detrimental effect on dynamic sports movements. 53 Therefore, several quickly performed exercises were included in this CGIP. 27 The post-intervention questionnaire also showed that the CS group conducted the quick leg raise and quick squats significantly more than the HB group (P < 0.01: unpresented data) when performing the programme in daily life.…”