Comparison Between The Effect Of Ballistic Stretching And Static Stretching On Maximal Voluntary Contraction

Abstract

Recent studies have shown that static stretching decreases maximal voluntary contraction (MVC) performance although static stretching can increase joint range of motion (ROM). It is suggested that the inhibited ?-motoneuron and/or reduced musculotendinous stiffness after static stretching consequently have a negative effect on contraction performances. Ballistic stretching as well as static stretching has also been used as a warm-up scheme to improve ROM. However, it is not clear whether ballistic stretching results in a decreased MVC. PURPOSE: The purpose of the present study was to compare the acute effect of ballistic stretching on MVC with that of static stretching. METHODS: Nine healthy young men completed three different conditions; control (CON; non-stretching), static stretching (SS), and ballistic stretching (BS). For the stretching conditions, the hamstrings of their dominant legs were stretched to the point where they were about to perceive discomfort. During SS condition, subjects held at the stretching position for 45-s. The BS was achieved by 45 bob-up and -down movements at a pace of 1 bob per sec. In both conditions, the stretching was repeated five times with a 15-sec rest between sets. Before and after each intervention, MVC of knee flexion and iEMG of biceps femoris muscle were recorded. The flexibility of the hamstrings (ROM) was also evaluated by Leighton flexometer in a spine position. RESULTS: A two-way repeated measures ANOVA showed a significant interaction between test (pre-and post-stretching) and condition (p< 0.05) in ROM and MVC. ROM increased after SS and BS by similar degrees [SS: 4.2 ± 4.6 °, BS: 5.1 ± 5.3 °] whereas control condition produced no changes in ROM. MVC was also decreased by SS and BS while control condition did not affect MVC [CON: pre; 101 ± 14 Nm, post; 98 ± 19 Nm, SS:pre; 108 ± 18 Nm, post; 94 ± 16 Nm, BS: pre; 105 ± 17 Nm, post; 99 ± 13 Nm]. The reduction in MVC was greater after SS than BS [SS: −12.0 ± 5.0 %, BS: −4.9 ± 4.8 %](p< 0.05). iEMG and iEMG/MVC were not altered by any conditions. CONCLUSIONS: Our findings indicate that the negative effect of BS on MVC is smaller than SS.