Abstract:

Muscular responses, rate of neuromuscular fatigue, and performance during seated row exercise may be affected by using a neutral wrist (NW) or a flexed wrist (FW) handle design. PURPOSE: To compare rate of fatigue differences between the Biceps Brachii (BB), Latissimus Dorsi (LD), and Flexor Carpi Radialis (FCR) across the two handle types during seated row exercise. A secondary purpose was to compare performance differences and rate of fatigue between genders. METHODS: A sample of 10 males (21.6 ± 1.30 yrs) and 10 females (22.1 ± 2.80 yrs) with prior resistance training experience (5.0 ± 2.5 yrs) completed a 1 repetition maximum (1-RM) seated row with both NW and FW handle types in a randomized order. This was followed by a maximal repetition set to failure using 85% 1-RM with both handle types in a randomized order. Electromyography of the BB, LD, and FCR were assessed during the maximal repetition set to failure at 85% 1-RM. Root mean square from the BB, LD, and FCR were determined for each repetition and slope coefficients were calculated for each maximal repetition set to determine rate of neuromuscular fatigue. Two-way mixed factorial ANOVAs were used to analyze gender and handle differences in 1-RM and number of repetitions to failure. Three-way mixed factorial ANOVA was used to analyze rate of fatigue between gender, muscle, and handle type. RESULTS: The 1-RM lifts were significantly greater (p< 0.001) with the FW handle (90.2 ± 30.5 kg) versus the NW handle (87.8 ± 30.4 kg). There were significant differences (p< 0.001) between genders for the 1-RM lifts across both handle types (males - FW: 117.3 ± 16.5 kg, NW: 114.5 ± 17.2 kg; females - FW: 63.2 ± 6.17 kg, NW: 61.1 ± 6.05 kg).  A significant handle×gender interaction (p=0.047) was noted for repetitions to failure at 85% 1-RM. Post hoc tests revealed that males completed the same number of repetitions with the NW (11.9±3.7 reps) and FW (11.2±2.4 reps) handles, while there was a trend (p=0.051) for females to complete more repetitions with the FW (12.7±3.7 reps) than NW (11.5±2.3 reps). There was no significant 3-way interaction (p=0.576) for the rate of fatigue. However, a trend (p=0.052) for a muscle×gender interaction was noted, and a significant main effect of muscle (p=0.014) was observed. Regardless of handle or gender, the LD (2.43±1.12 mV/rep) had a significantly (p=0.014) greater rate of fatigue than the BB (1.22±1.24mV/rep) or FCR (0.41±2.19 mV/rep). CONCLUSIONS: These findings showed significantly higher 1-RM with the FW handle type. Furthermore, females may be able to complete a greater number of repetitions to failure with the FW handle when compared to NW. Finally, neuromuscular fatigue was not affected by gender or handle types, but the LD had the greatest neuromuscular fatigue during the seated row. Possible mechanisms for the 1-RM differences may be related to actin and myosin overlap of the forearm flexors, ergonomic factors such as grip comfort and differences in handle contact surface area. PRACTICAL APPLICATIONS: Alterations in wrist positioning during seated row exercise was shown to result in significant increases in 1-RM for both genders and in repetitions to failure for females only. These findings are important from an equipment design, training, and performance perspective.  Using the WF handle allows for a greater amount of weight to be lifted, and may ultimately improve overall development of strength.