Effect of 15 days of betaine ingestion on concentric and eccentric force outputs
during isokinetic exercise. J Strength Cond Res 25(8): 2235-2241,
2011—The purpose of this study was to examine the efficacy of 15 days of betaine
supplementation on peak concentric (CON) and eccentric (ECC) force during
isokinetic exercise in active college-aged men. Eleven men volunteered for this
study (21.7 ± 5.1 years; height: 178.5 ± 6.4 cm; body mass: 79.8 ± 10.3 kg).
Subjects were randomly assigned to either a supplement (BET) or placebo (PL)
group. Supplementation occurred for 15 days. Subjects reported to the Human
Performance Laboratory on 5 occasions during this period, separated by 72 hours,
for a testing and exercise session on an isokinetic chest press device. After
each exercise protocol, subjects rated their fatigue and muscle soreness on a
15-cm visual analog scale. Subjects then consumed no daily BET for 4 weeks but
maintained familiarity with the exercise device once per week. After the washout
period, subjects resumed the BET protocol using the opposite drink and repeated
the same 15-day protocol. No differences were noted in maximum CON force output
between pre (335.9 ± 78.3 and 321.6 ± 63.6 N) and post (330.3 ± 74.8 and 330.2 ±
71.6 N) workouts in both BET and PL, respectively. In addition, no differences
were noted in maximum ECC force output between pre (352.0 ± 90.6 and 324.4 ±
85.2 N) and post (353.2 ± 98.2 and 366.9 ± 128.5 N) workouts in BET and PL,
respectively. No differences in subjective measures of soreness and fatigue were
seen, but a significant reduction in Δ fatigue was observed in BET compared to
PL. In conclusion, 15 days of betaine supplementation did not increase peak CON
or ECC force outputs during an isokinetic chest press but did appear to reduce
subjective measures of fatigue to the exercise protocol.
Hoffman, J.R., et al., Effect of 15 Days of Betaine Ingestion on Concentric and Eccentric Force Outputs During Isokinetic Exercise. The Journal of Strength & Conditioning Research, 2011. 25(8): p. 2235-2241.