Serum brain-derived neurotrophic factor (BDNF) and self-paced time-trial performance in older untrained men.

PURPOSE: This study examined the effect of 12 weeks of concurrent aerobic and resistance training on brain derived neurotrophic factor (BDNF) levels, neuromuscular performance and cerebral oxygenation on self-paced cycling exercise in previously untrained older men. METHODS: Eight untrained healthy males aged 53-64 years performed a familiarisation and a pre-training self-paced cycling time trial before 12 weeks of exercise training which combined aerobic and resistance exercise. The self-paced cycling time trial comprised a 30 s maximal effort sprint for every 4.5 min of lower intensity pace for a total of 25 min. Upon completion of 12 weeks of training, a comparison of the pre-training trial analysed for serum BDNF, neuromuscular performance, and cerebral oxygenation was undertaken. RESULTS: Serum BDNF decreased significantly from 10.02 ± 4.63 to 6.96 ± 3.56 ng/ml after 12 weeks of training. There was also attenuated physiological strain for a comparable self-paced cycling performance. Despite positive physiological responses during the time trial pacing strategy was not altered compared with pre training. CONCLUSION: BDNF decreases following 12 weeks of concurrent training and might reflect neuroplasticity for this type of training stimulus. Exercise training in previously sedentary older men can result in a multitude of physical benefits, which may also confer a neuroprotective effect. However, specific training is required to improve pacing strategies in previously untrained older males. CLINICAL TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry number ACTRN12622001477718.

Weight-Cutting Implications for Competition Outcomes in Mixed Martial Arts Cage Fighting.

ABSTRACT: Brechney, GC, Chia, E, and Moreland, AT. Weight-cutting implications for competition outcomes in mixed martial arts cage fighting. J Strength Cond Res 35(12): 3420-3424, 2021-Weight cutting is common among amateur and professional mixed martial arts (MMA) competitors because of the belief that it provides an advantage in combat sports. This study aimed to identify whether fight outcome (win vs. loss vs. type of loss) was influenced by magnitudes of body mass (BM) lost through weight cutting and BM regained before the fight after official weigh-in in amateur and professional MMA athletes with previous weight-cutting experience. Body mass data were collected using self-report from 75 MMA athletes (59 amateur and 16 professional) before commencing weight-cutting practices 7 days before weigh-in, by the regulating body at their official weigh-in 24 hours before the fight and through direct measurement immediately before competition. Data were analyzed according to win; loss by technical knockout or knockout (KO); loss by submission; or loss by the judge's decision. Athletes who lost their fight cut significantly more BM (10.6%) compared with athletes who won (8.6%) (p = 0.04, d = 0.48, 95% confidence interval [CI] = 0.02-0.93), but there were no differences between types of loss. There were no significant differences in recovered BM between athletes who won (6.8%) vs. lost (7.4%), or type of loss. Furthermore, there was a significant relationship between greater magnitudes of BM cut and greater likelihood of losing the fight (B = -0.12, P = 0.048), odd ratio 0.89 (95% CI: 0.79-1.00). This study provides the first line of evidence that excessive weight cutting may be detrimental to fight outcome in MMA.

The effects of acute versus chronic training status on pacing strategies of older men in a hot, humid environment.

The combined effects of age and training on the regulation of exercise performance may be confounded by the additional challenge of thermoregulation. Thus, the objective of this study was to compare the pacing strategy of older men who have recently completed 12 weeks of exercise training (acute) to men who have been regularly (>3 times/week) training for at least 6 months (chronic) in a hot, humid environment and to observe disparity, if any, between acute and chronic exercise training on thermoregulation. Eleven chronically trained men (OT) completed a familiarisation trial before returning after 7-10 days to repeat the protocol. Similarly, eight untrained men (OU-PRE) were familiarised and repeated the protocol before completing 12 weeks of exercise training. Post-training, the eight acutely trained men (OU-POST) returned to the laboratory for a third trial. All trials were conducted on a cycle ergometer at the same time of the day in a climate controlled chamber with a mean dry bulb temperature and relative humidity of 32.0°C and 68%, respectively. OT consumed more water than OU-POST and OU-PRE (P<0.01) whilst no differences were observed in the OU with training. Voluntary activation of the knee extensors decreased by 11.3% (P<0.05) in the OU-PRE after the cycling time trial. However, the decrease in voluntary activation observed in the OU-POST and OT after the cycling time trial were not significant. The OT maintained a higher power output compared with the OU-POST and OU-PRE except for the last sprint, whilst no significant differences in power output were observed between the OU-PRE and OU-POST. The rate of rise in core temperature was significantly higher in the OT compared with OU-POST (P<0.001) and OU-PRE (P<0.001). With more experience in training, the OT used an alternative hydration strategy compared with the OU-POST and OU-PRE to mitigate the effects of possible exercise hyperthermia, ultimately attaining a higher, but non-critical core temperature at the end of the cycling time trial. Twelve weeks of exercise training may not manifest in improved exercise performance per se, but could translate to improved performance of activities of daily and independent living.