(2) COMPARISON OF MUSCLE ACTIVITY DURING JUDO/JIU-JITSU SPECIFIC PULL-UP AND NEUTRAL PULL-UP GRIPS

Judo and jiu-jitsu are grappling-based systems of combat traditionally performed in a heavy cotton jacket (kimono/gi). A kimono/gi wrapped around a pull-up bar can be used to conduct sport-specific grip endurance and strength tests. No studies have compared the electrical activity (EA) during pull-ups utilizing a neutral grip (NPUG) to those utilizing a judo/jiu-jitsu specific grip (JPUG).

Purpose: In order to assess the degree to which a JPUG challenges the hand flexor (HF) and biceps brachii (BB) musculature, this study investigated the EA of the HF and BB muscle groups while utilizing NPUG and JPUG. It was hypothesized that there would be higher HF muscle EA in JPUG compared to NPUG, but similar EA in the BB between grips.

Methods: Eighteen participants ((mean ± SE): age = 20.8 ± 0.3 yr, height = 175.9 ± 1.4 cm, body mass = 82.1 ± 3.1 kg, body fat = 12.7 ± 1.5 %, grip strength = 53.0 ± 2.2 kg, NPUG repetition maximum (RM) = 8.8 ± 0.8, JPUG RM = 8.5 ± 0.7) were randomly assigned to perform NPUG and JPUG 24 hr apart using a randomized within-subjects, cross-over design. Surface electromyography (sEMG) was measured on the HF and BB during maximal isometric voluntary contractions (MIVC) prior to each trial, followed by NPUG or JPUG repetitions (reps) to failure. For each participant, the average sEMG of the first five reps for NPUG and JPUG was calculated and divided by the MIVC recorded at the respective visit for the HF and BB to determine the relative activity (RA; %). Separate 2 × 5 (Grip × Rep) RMANOVAs were used to evaluate the effects of grip and rep on EA. Separate dependent t tests were used to evaluate RA of the HF and BB between grips. Significance was set at p</em> ≤ .05.

Results: For the HF, there was no interaction (p = .170). There was a main effect of rep (Rep 1 < Rep 2 < Rep 3 < Rep 4 < Rep 5, p < .0005) and grip (JPUG > NPUG, p = .025). For the BB, there was no interaction (p = .541). There was a main effect of rep (Rep 2 < Rep 3 < Rep 4 < Rep 5, p = .002), but no main effect of grip (p = .408). Results of the dependent sample t tests indicated no difference in the RA of the HF between NPUG (186.3 ± 24.1%) and JPUG (223.2 ± 34.6%) conditions (p = .19). In addition, there was no difference in the RA of the BB between NPUG (60.0 ± 7.2%) and JPUG (64.6 ± 9.3%) conditions, (p = .62).

Conclusion: The present study indicates that both the NPUG and JPUG exhibited predictable and anticipated increases in EA in the HF and BB musculature as reps advanced throughout a set (i.e., increased muscular activity as fatigue increased). Higher HF EA was observed while using JPUG when compared to NPUG. However, similar EA was observed in the BB between the two grips. PRACTICAL APPLICATION: The results of this study suggest that utilizing a kimono/gi to facilitate a sport-specific, judo/jiu-jitsu pull-up grip involving a mid-acromion width grip with hands in a neutral position results in higher EA in the HF compared to a neutral, mid-acromion grip pull-up performed on a standard pull-up bar. Attempts at improving sport-specific strength and endurance of the forearm musculature, arguably an important determinant in the outcome of a match, should therefore incorporate a judo/jiu-jitsu pull-up grip.

 

Acknowledgements: None