Acute Citrulline-Malate Supplementation Increases Total Work in Short Lower-Body Isokinetic Tasks for Recreationally Active Females During Menstruation.

ABSTRACT: Gills, JL, Spliker, B, Glenn, JM, Szymanski, D, Romer, B, Lu, H-C, and Gray, M. Acute citrulline-malate supplementation increases total work in short lower-body isokinetic tasks for recreationally active females during menstruation. J Strength Cond Res 37(6): 1225-1230, 2023-Citrulline-malate (CM) exhibits acute ergogenic benefits through nitric oxide production (NO) and augmentation of vasodilatory properties. Nitric oxide is upregulated by estrogen and may influence CM's ergogenic efficacy in women. Therefore, the objective of this study was to evaluate the acute effects of CM supplementation on lower-body isokinetic performance in recreationally active women. Nineteen women (23.5 ± 3.1 years; 164.8 ± 7.0 cm; 61.9 ± 27.4 kg; 28.8 ± 8.1% body fat) completed 2 randomized, double-blind, crossover trials consuming CM (8 g CM + 12 g dextrose) or placebo (12 g dextrose). For testing trials, subjects were in the menstruating portion of the follicular phase of their menstrual cycle. Subjects performed a 5-repetition isokinetic leg extension protocol (5RP) followed by a 50-repetition isokinetic leg extension protocol (50RP), 60 minutes after supplement consumption. Repeated measures analysis of variance analysis showed that CM significantly increased total work completed, relative total work, and total work during maximum repetition compared with placebo ( p < 0.05); but no significant performance differences existed between trials for peak torque production ( p = 0.14) for the 5RP. No significant differences were identified between trials for peak torque production ( p = 0.69 ) or total work ( p = 0.33) completed during the 50RP. CM increased total work completed during the 5RP, but provided no ergogenic benefit during the 50RP in recreationally active menstruating women. CM amplifies power-based resistance exercise performance in women during the follicular phase of the menstrual cycle, potentially because of depressed estrogen levels. Additional research is needed to identify timing efficacy of CM to increase sport performance during each phase of the menstrual cycle.

Acute citrulline-malate supplementation is ineffective during aerobic cycling and subsequent anaerobic performance in recreationally active males.

Citrulline-malate (CM) purportedly increases exercise performance through increased nitric oxide production. The effects of CM on muscular strength performance are well-documented; however, the benefits of CM on aerobic and anaerobic biking performance are not well researched. Therefore, the present investigation examined the acute CM supplementation effects on aerobic and anaerobic cycling performance in recreationally active males. Methods: 28 recreationally active males (20.9 ± 2.8 years) completed randomized, double-blind, crossover trials consuming CM (12g dextrose + 8g CM) or a placebo (12g dextrose). Participants performed an aerobic cycling protocol (time-to-exhaustion [TTE]), followed by a subsequent 30-second Wingate cycling test, 60-minutes after supplement consumption. Results: Dependent t-tests showed no significant differences (p > 0.05) for TTE (PLA: 315.4 s ± 137.7 s; CM: 314.1 s ± 107.1 s) and Total Work Completed (TWC) (PLA: 74.7 ± 34.1 kilojoules (kJ); CM: 74.1 ± 26.4 kJ) during the aerobic cycling protocol. Dependent t-tests also showed no significant differences (p > 0.05) for mean watts (PLA: 586.1 ± 87.7 Watts (W); CM: 588.0 ± 93.0 W), peak watts (PLA: 773.0 ± 136.7 W; CM: 786.7 ± 133.0 W), and fatigue index (PLA: 12.9 ± 6.4 FI; CM: 14.3 ± 7.2 FI) during the Wingate protocol. Repeated-measures ANOVA results indicated a significant effect between each 5 s interval (p < 0.001), but no differences were observed between trials (p > 0.05). Conclusion: Acute CM supplementation in recreationally active males provides no ergogenic benefit in aerobic cycling performance followed by an anaerobic cycling test.

Footwear Alters Lower Extremity Coordination Variability.

Footwear has been shown to have a significant effect on numerous kinematic and kinetic variables during walking and running. While footwear mass is an indisputably important influence on gait patterns, we suspected that the amount of outsole material on most footwear would likely diminish or delay the integration of tactile feedback in motor control strategies during gait. Thus, we designed this study to investigate the influence of footwear and augmented tactile feedback on lower extremity coordination patterns during walking. A secondary purpose of the study was to examine gender differences in response to altered footwear conditions. Forty-eight participants (24 male and 24 females) walked during four standardized footwear conditions (barefoot, shod, barefoot with augmented tactile feedback, and shod with augmented tactile feedback), and we collected three-dimensional kinematic data and calculated continuous relative phase values for two adjacent lower extremity joints to determine interjoint coordination patterns. We used deviation phase and the mean of the continuous relative phase to compare motor coordination patterns across conditions. We found significant footwear and gender effects for spatiotemporal variables but only significant footwear effects for motor coordination patterns. Females displayed a significantly higher cadence and shorter height-normalized stride length as compared to males. Participants displayed significantly greater thigh-shank coordination variability in the shod, as compared to the unshod, conditions. Thus, footwear results in a diminished or delayed tactile feedback that alters neuromuscular control strategies during walking.

Kinetic Analysis of Swimming Flip-Turn Push-Off Techniques.

The aims of the present study were to examine the influences of different push-off techniques on kinetic and kinematic parameters both in and out of the water. The two techniques were: (1) a push off that was characterized by rapid extension of knees and hips towards the wall, prior to contact (i.e., no countermovement), and, (2) where the swimmer glides into the wall, letting the wall flex the knees in an approximate countermovement or eccentric phase. Twenty trained male and female freestyle swimmers (age 26.1 ± 9.9 years, height 1.61 ± 0.04 m, and weight 65.6 ± 19.3 kg) participated. Data were analyzed by employing two (i.e., land and water) 3 (variables of interest) x 2 (push-off type) repeated measures ANOVAs with the alpha level set a priori at 05. Results indicated that there were significant main effects for peak perpendicular force (p < 0.001), perpendicular impulse (p = 0.018), and velocity at 2.5 m (p = 0.005) on land. However, no significant effects were found between techniques in the water trials. As many of the participants were master swimmers, it is possible that they were unable to approach the wall in the water at the requisite speed to elicit a benefit from the countermovement.