Effect of Sodium Bicarbonate Supplementation on Muscle Performance and Muscle Damage: A Double Blind, Randomized Crossover Study.

Sodium bicarbonate (NaHCO3) has been used as an ergogenic substance during high-intensity exercises. Therefore, the aim of the present study was to investigate the effects of NaHCO3 supplementation on external and internal load parameters during isokinetic exercise in trained subjects. Ten subjects were tested on two occasions: after ingesting 0.3 g.kg-1 of body mass of NaHCO3 or placebo. Maximum voluntary isometric contraction was performed before and after a dynamic protocol consisting of 10 series of 10 movements of flexion/extension of the knee extensors at 120° s-1 at an interval of 60 s between series. Outcomes considered were: peak torque (isokinetic dynamometry), blood lactate and creatine concentration (CK), analysis of perceptions of effort (OMNI scale), pain (visual analog scale) and recovery (scale raging 6 to 20). Performance was assessed using peak torque values. Muscle damage was assessed prior and 24 h post exercise. The subjective perceptions of effort, pain and recovery were assessed at different times and the internal load of the session was assessed 30 min post-effort. Although significant reductions in peak torque were noted both in isometric (NaHCO3:-29.11 ± 22.95%, Placebo: -23.51 ± 15.23%; p = 0.38) and isokinetic strength (NaHCO3:-23.0 ± 13.9%, Placebo:-19.6 ± 9.1%; p = 0.09), there was no effect of supplementation on performance (p > 0.05). The blood CK concentrations (NaHCO3: pre:225.3 ± 135.9 U/L, post: 418.4 ± 318.4 U/L; Placebo: pre:238 ± 94.03 U/L, post:486 ± 336.6 U/L) increased after protocol (p = 0.005), however, without differences between conditions. In conclusion, the NaHCO3 did not attribute benefits in performance or in parameters related to the internal load of exercise.

Effects of 12 Weeks of Tai Chi Intervention in Patients With Chronic Ankle Instability: A Randomized Controlled Trial.

CONTEXT: Tai Chi is a physical activity modality which is widely practiced over the world. The effectiveness of Tai Chi on postural control and balance has been described in older population, but until recently there are no studies that include patients with chronic ankle instability. OBJECTIVES: The aim of this study was to evaluate the effectiveness of 12 weeks of Tai Chi intervention on dynamic balance and self-reported instability in patients with chronic ankle instability. STUDY DESIGN: A randomized controlled trial was carried out. SETTING: University physical therapy facility. PARTICIPANTS: Fifty-two participants were allocated to an intervention group (n = 26) based on Tai Chi training or a control group (n = 26) who received no intervention. INTERVENTION: The participants completed 12 weeks of Tai Chi intervention (1 h session/2 times per week) or no intervention in the control group. MAIN OUTCOME MEASURES: Outcome measures included postural control and self-reported instability feeling assessed by the Star Excursion Balance Test and the Cumberland Ankle Instability Tool, respectively. RESULTS: There was observed significant improvement in all Star Excursion Balance Test reach distances (anterior [F = 6.26, P < .01]; posteromedial [F = 9.58, P < .01], and posterolateral [F = 8.42, P < .01]) in the Tai Chi group with no change in the control group (P < .01). The intervention group demonstrated significant improvement on self-reported instability feeling assessed by the Cumberland Ankle Instability Tool questionnaire (F = 21.36, P < .01). CONCLUSION: The obtained results suggested that 12 weeks of Tai Chi intervention have positive effects on postural control and self-reported instability feeling in patients with chronic ankle instability.

Repeated sprint ability is not enhanced by caffeine, arginine, and branched-chain amino acids in moderately trained soccer players.

The aim was to investigate the effect of a dietary supplementation on the repeated sprint ability (RSA) performance in recreationally trained team sports athletes. Twelve young men underwent a RSA exercise protocol in five trials, in which participants ingested carbohydrates (CHO) plus caffeine (Caf), CHO plus arginine (Arg), CHO plus branched-chain amino acids (BCAA), CHO plus Caf, Arg, and BCAA (ALL), and CHO only. Heart rate, oxygen saturation, hematic lactate, ratings of perceived exertion, average sprint time, total time, best sprint time, peak power, and average power were taken. Data revealed no significant effects neither on physiological nor performance parameters with any of the supplements.