β-alanine is an amino acid that, when combined with histidine, forms the dipeptide carnosine within skeletal muscle. Carnosine and β-alanine each have multiple purposes within the human body; this review focuses on their roles as ergogenic aids to exercise performance and suggests how to best quantify the former’s merits as a buffer. Carnosine normally makes a small contribution to a cell’s total buffer capacity; yet β-alanine supplementation raises intracellular carnosine concentrations that in turn improve a muscle’s ability to buffer protons. Numerous studies assessed the impact of oral β-alanine intake on muscle carnosine levels and exercise performance. β-alanine may best act as an ergogenic aid when metabolic acidosis is the primary factor for compromised exercise performance. Blood lactate kinetics, whereby the concentration of the metabolite is measured as it enters and leaves the vasculature over time, affords the best opportunity to assess the merits of β-alanine supplementation’s ergogenic effect. Optimal β-alanine dosages have not been determined for persons of different ages, genders and nutritional/health conditions. Doses as high as 6.4 g day−1, for ten weeks have been administered to healthy subjects. Paraesthesia is to date the only side effect from oral β-alanine ingestion. The severity and duration of paraesthesia episodes are dose-dependent. It may be unwise for persons with a history of paraesthesia to ingest β-alanine. As for any supplement, caution should be exercised with β-alanine supplementation.

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BACKGROUND: Few studies examined lactate, testosterone and cortisol changes from supramaximal exercise done by women. OBJECTIVE: Assess the impact of repetition type and exercise history/background on lactate, cortisol and testosterone changes from high-speed workouts done by women. METHODS: College-age women (11 competitive athletes, 18 novice athletes) performed two high-speed workouts on an Impulse resistive exercise machine. Each workout entailed two 60-second sets of either tonic or phasic repetitions. There were two hormonal (pre-and post-exercise) measurements per workout. Lactate was measured six times (pre-, and at zero-, five-, ten, 15and 20-minutes post-exercise). RESULTS: Mean force showed a main effect for workout (tonic > phasic). Lactate had a time main effect, as zero-, five-and ten-minutes post-exercise results were significantly higher than 15-and 20-minutes post-exercise values as well as pre-exercise data. Cortisol had a group main effect (competitive > novice). Testosterone results included a time effect trend (p = 0.12) for higher post-exercise values. CONCLUSIONS: Results warrant continued inquiry regarding 1): pre-and post-workout salivary hormonal assays, and 2): acute testosterone changes from high-speed supramaximal exercise done by female athletes.

In-flight resistive exercise workouts are performed on novel flywheel-based hardware. Designs of such workouts may be better served by measuring changes to lactate and testosterone values. To make workouts pertinent to μg they should utilize unique features of flywheel-based hardware, such as the option to exert eccentric torque. Our study compares changes to blood lactate and testosterone concentrations ([BLa-], [T]) from leg press workouts that differ by contractile mode and work volume, on a flywheel ergometer. Subjects performed three workouts; two entailed two sets of concentric-eccentric (CE2) or concentric-only (CO2) actions. A third involved four sets of concentric-only actions (CO4). Workouts entailed eight-repetition sets with 90-second rest periods. Total work (TW) was quantified per workout. [T] were assessed, both pre- and post-exercise. [BLa-] were measured pre- and at 0-, 5-, 10-, 15-, and 20-minutes post-exercise. TW was assessed with a one-way analysis of variance (ANOVA). [BLa-] and [T] were evaluated with two- and three-factor ANOVAs, respectively. Scheffe’s test was our post-hoc. TW data had an inter-workout (CE2, CO4 > CO2) difference. [BLa-] included a two-way interaction as CO4 workouts evoked higher post-exercise values. Results for [T] produced gender (men > women) and time (post > pre) main effects. Our results imply flywheel-based workouts with a large volume of concentric actions evoke no greater increase in [T] than workouts with only half the muscle shortening activity, despite attainment of higher TW and post-workout [BLa-].