RESUMEN
PURPOSE: To examine the skeletal muscle and performance responses across two different exercise training modalities which are highly applied in soccer training. METHODS: Using an RCT design, 39 well-trained male soccer players were randomized into either a speed endurance training (SET; n = 21) or a small-sided game group (SSG; n = 18). Over 4 weeks, thrice weekly, SET performed 6-10 × 30-s all-out runs with 3-min recovery, while SSG completed 2 × 7-9-min small-sided games with 2-min recovery. Muscle biopsies were obtained from m. vastus lateralis pre and post intervention and were subsequently analysed for metabolic enzyme activity and muscle protein expression. Moreover, the Yo-Yo Intermittent Recovery level 2 test (Yo-Yo IR2) was performed. RESULTS: Muscle CS maximal activity increased (P < 0.05) by 18% in SET only, demonstrating larger (P < 0.05) improvement than SSG, while HAD activity increased (P < 0.05) by 24% in both groups. Na+-K+ ATPase α1 subunit protein expression increased (P < 0.05) in SET and SSG (19 and 37%, respectively), while MCT4 protein expression rose (P < 0.05) by 30 and 61% in SET and SSG, respectively. SOD2 protein expression increased (P < 0.05) by 28 and 37% in SET and SSG, respectively, while GLUT-4 protein expression increased (P < 0.05) by 40% in SSG only. Finally, SET displayed 39% greater improvement (P < 0.05) in Yo-Yo IR2 performance than SSG. CONCLUSION: Speed endurance training improved muscle oxidative capacity and exercise performance more pronouncedly than small-sided game training, but comparable responses were in muscle ion transporters and antioxidative capacity in well-trained male soccer players.
Asunto(s)
Adaptación Fisiológica , Entrenamiento de Intervalos de Alta Intensidad/métodos , Músculo Esquelético/fisiología , Resistencia Física , Fútbol/fisiología , Entrenamiento de Intervalos de Alta Intensidad/efectos adversos , Humanos , Masculino , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Adulto JovenRESUMEN
PURPOSE: If ß-alanine supplementation counteracts muscular fatigue development or improves athletic performance was investigated. METHODS: Elite kayak rowers (10 men and 7 women) were supplemented with either 80 mg·kg body mass·d of ß-alanine or placebo for 8 wk. Muscular fatigue development was investigated by applying a 2-min elbow flexor maximal voluntary contraction (MVC). EMG was recorded continuously, and voluntary activation was determined 30, 60, 90, and 115 s into the 2-min MVC. In addition, performance was evaluated as 1000-m and 5 × 250-m kayak ergometer rowing. RESULTS: Force reduction during the 2-min MVC was similar before and after supplementation with ß-alanine (30.9% ± 10.3% vs 36.0% ± 14.1%) and placebo (35.5% ± 7.7% vs 35.1% ± 8.0%). No time effect was apparent in voluntary activation during the 2-min MVC. In addition, there was no detectable effect of ß-alanine supplementation on 1000-m kayak ergometer performance (ß-alanine: 0.26% ± 0.02% vs placebo: -0.18% ± 0.02%) or accumulated 5 × 250-m time (ß-alanine: -1.0% ± 0.3% vs placebo: -1.0% ± 0.2%). In 5 × 250 m, mean power output was reduced to a similar extent from first to fifth interval before and after supplementation with ß-alanine (23% ± 11% vs 22% ± 10%) and placebo (26% ± 13% vs 20% ± 5%). CONCLUSIONS: Two-minute MVC characteristics are unaffected by ß-alanine supplementation in elite kayakers, and likewise, both a 1000-m kayak ergometer time trial lasting 4-5 min and a 5 × 250-m repeated sprint ability were unaltered by supplementation.
Asunto(s)
Rendimiento Atlético , Suplementos Dietéticos , Músculo Esquelético/efectos de los fármacos , Fenómenos Fisiológicos en la Nutrición Deportiva , Deportes Acuáticos/fisiología , beta-Alanina/administración & dosificación , Adulto , Ergometría , Femenino , Humanos , Masculino , Fatiga Muscular , Músculo Esquelético/fisiología , Sustancias para Mejorar el Rendimiento/administración & dosificación , Adulto JovenRESUMEN
It was evaluated whether upper-body compared to lower-body musculature exhibits a different phenotype in relation to capacity for handling reactive oxygen species (ROS), H+, La-, Na+, K+ and also whether it differs in adaptive potential to exercise training. Eighty-three sedentary premenopausal women aged 45 ± 6 years (mean ± SD) were randomized into a high-intensity intermittent swimming group (HIS, n = 21), a moderate-intensity swimming group (MOS, n = 21), a soccer group (SOC, n = 21), or a control group (CON, n = 20). Intervention groups completed three weekly training sessions for 15 weeks, and pre- and postintervention biopsies were obtained from deltoideus and vastus lateralis muscle. Before training, monocarboxylate transporter 4 (MCT4), Na+/K+ pump α2, and superoxide dismutase 2 (SOD2) expressions were lower (P < 0.05) in m deltoideus than in m vastus lateralis, whereas deltoid had higher (P < 0.05) Na+/H+ exchanger 1 (NHE1) expression. As a result of training, Na+/K+ pump α2 isoform expression was elevated only in deltoideus muscle, while upregulation (P < 0.05) of the α1 and ß1 subunits, phospholemman (FXYD1), NHE1, and superoxide dismutase 1 expression occurred exclusively in vastus lateralis muscle. The increased (P < 0.05) expression of MCT4 and SOD2 in deltoid muscle after HIS and vastus lateralis muscle after SOC were similar. In conclusion, arm musculature displays lower basal ROS, La-, K+ handling capability but higher Na+-dependent H+ extrusion capacity than leg musculature. Training-induced changes in the ion-transporting and antioxidant proteins clearly differed between muscle groups.