The Acute Effect of Dynamic Neural Mobilization Exercise versus Static Stretching on Muscular Strength and Power in Martial Artists

Abstract

BACKGROUND: The effect of dynamic neural mobilisation exercise on muscular strength and power and jump power in martial artists is currently unknown. Stretching techniques are commonly used within exercise programmes, warm-ups, conditioning sessions, and cool-downs to achieve benefits and improve fitness. The benefits of stretching in some cases accompany consequences to strength and power, which may decrease subsequent physical performance, including competitive sport performance or even impact activities of daily living. Prolonged static stretching (>1 minute) causes stretch induced strength loss reducing performance of subsequent strength and power tasks, but it is not known whether neural mobilisation exercise also reduces strength and power. Biokineticists and others involved in exercise can make better decisions and plans to maximize benefits and minimize harms to their clients by knowing the effects of specific exercise techniques like static stretching and dynamic neural mobilisation exercise. OBJECTIVES: To determine the acute effect of static stretching on muscular strength, power and jump power in martial artists. To determine the acute effect of dynamic neural mobilisation exercise on strength, power and jump power in martial artists. To determine whether there is a difference between the acute effects of static stretching and dynamic neural mobilisation exercise on muscular strength, power and jump power in martial artists. METHODS: A randomised controlled trial measured the effects of static stretching and dynamic neural mobilisation exercise on 93 martial artists (75 male and 18 female, apparently healthy participants, aged 26.3 ± 4.5 years from Mixed Martial Arts, Jiu jitsu, Karate, Kung fu and Taekwondo). The sample was split into three equal groups (control, static stretching and dynamic neural mobilisation, n = 31) using randomisation software. Participants were randomised equally within gender and martial art to each group. At individual appointments, they received an information sheet, informed consent, biographic and screening questionnaire. Baseline testing included height, weight, BMI and three skinfolds. Warm-up was a five-minute stationary cycle (25 to 75 watts at 40 to 60% Heart Rate Reserve). Dominant then non-dominant leg isokinetics followed at 60, 180 and 300⁰.s-1 with familiarisation trials before each speed with inter- set (120 seconds) and inter-side rest (180 seconds). Counter Movement Jump (CMJ) immediately followed with three submaximal familiarisation trials and five maximal v attempts. A 15-minute recovery-period of sitting or slow, gentle walking followed, before the control or experimental conditions. The control was 10 minutes of sitting or slow, gentle walking. The static stretching group did 1-minute of dominant leg supine assisted hamstring static stretch with cervical extension and ankle plantar flexion at the point of “maximum tolerated stretch”, alternated with the non-dominant leg for 5 sets and 10 minutes total. The dynamic neural mobilisation exercise group did 1 minute of seated dominant leg alternating knee extension flexion with neck, thoracic spine and ankle maintained in flexion and till the point of “maximum tolerated stretch” alternated with the non-dominant leg for 5 sets and 10 minutes total. Post-test Isokinetics and CMJ and a stationary cycle cool-down followed. Data analysis used SPSS. Paired t-tests compared pre-, and post-test means. One-Way between- subjects ANOVAs and Bonferroni post hoc tests compared post-test means. Descriptive statistics were generated for all variables. Data was tested for normality and outliers and significance was accepted at 95% (p = 0.05). RESULTS: Ninety-three martial artists (age: 26.3 ± 4.5 years) were included in this study. Anthropometry: Body mass: 74.9 ± 14.4 kg, height: 173.5 ± 8.9 cm; body mass index: 24.8 ± 7.6 kg.m-2, body fat percent: 14 ± 7.6%, fat mass: 10.8 ± 7.1 kg and lean mass: 64 ± 11.6 kg. Muscle strength: No significant differences were identified between post-test means for control, static stretching, and dynamic neural mobilisation (DNME) with one-way between-subjects analysis of variances (ANOVA). Significant decreases and increases (p ≤ 0.05) were identified in the pre-post comparison with paired t-tests. In knee extension (dominant leg), significant changes were identified for absolute peak torque (aPT), peak torque / body weight (PT/BW) in all groups. The largest decreases were at 60⁰.s-1 (DNME and static stretching: ~∆ -10.6% and control group ~∆ -6.8%). In knee flexion (non-dominant) at 180⁰.s-1, for the control group there were significant increases in absolute peak torque (78.13 ± 22.27 to 81.58 ± 23.02 NM, p = 0.02) and peak torque / body weight (102.31 ± 21.23 to 106.43 ± 20.09 Nm.kg- 1, p = 0.03), however there were no changes in the static stretch of DNME groups. In knee extension (non-dominant leg) at 60⁰.s-1, static stretching significantly decreased aPT (189.12 ± 43.47 to 191.12 ± 40.56 Nm, p < 0.001) and PT/BW (295.76 ± 44.19 to 263.87 ± 39.78 Nm.kg-1) without changes in the control or DDME groups. Mean Power: In knee flexion (dominant leg), DNME significantly decreased mean power at 60, 180 and 300⁰.s-1, without changes in the static stretching or control group. In knee extension (non-dominant leg) and flexion (non-dominant leg), static stretching vi significantly increased mean power, without changes in the control or DNME group. Jump power: No significant changes in counter movement jump scores were identified in pre-post or post-post comparisons in any group. Conclusion: In pre-post comparison, 10 minutes of both static stretching and dynamic neural mobilisation led to significant (p ≤ 0.05) acute decreases in muscle strength and power for knee extension and flexion at 60, 180, 300⁰.s-1 in martial artists, even after prior physical exercise. Effects differed per leg and per speed and were in some cases accompanied by significant decreases in the control group. Only static stretching increased mean power in non-dominant leg knee flexion and extension at 300⁰.s-1. Increases in the control group at 180⁰.s-1 did not occur in static stretching or DNME groups. Jump power was unchanged. Between-subjects ANOVA identified no significant differences between post-test means for control and static stretching or dynamic neural mobilisation exercise, which could suggest small effect sizes or high sample variance. This study suggests that in pre-post comparison both static stretching and dynamic neural mobilisation similarly decreased performance, however post-post comparison identified no significant difference from control.