Abstract：
BACKGROUND: Neuromuscular function is considered as a determinant factor of endurance performance during adulthood. However, whether endurance training triggers further neuromuscular adaptations exceeding those of growth and maturation alone over the rapid adolescent growth period is yet to be determined.
OBJECTIVE: The present study investigated the concurrent role of growth, maturation, and endurance training on neuromuscular function through a 9-month training period in adolescent triathletes.
METHODS: Thirty-eight 13- to 15-year-old males (23 triathletes [~6 h/week endurance training] and 15 untrained [<2 h/week endurance activity]) were evaluated before and after a 9-month triathlon training season. Maximal oxygen uptake (V̇O2max) and power at V̇O2max were assessed during incremental cycling. Knee extensor maximal voluntary isometric contraction torque (MVCISO) was measured and the voluntary activation level (VAL) was determined using the twitch interpolation technique. Knee extensor doublet peak torque (T100Hz) and normalized vastus lateralis (VL) electromyographic activity (EMG/M-wave) were also determined. VL and rectus femoris (RF) muscle architecture was assessed using ultrasonography.
RESULTS: Absolute V̇O2max increased similarly in both groups but power at V̇O2max only significantly increased in triathletes (+13.8%). MVCISO (+14.4%), VL (+4.4%), and RF (+15.8%) muscle thicknesses and RF pennation angle (+22.1%) increased over the 9-month period in both groups similarly (p < 0.01), although no changes were observed in T100Hz, VAL, or VL EMG/M-wave. No changes were detected in any neuromuscular variables, except for coactivation.
CONCLUSIONS: Endurance training did not induce detectible, additional neuromuscular adaptations. However, the training-specific cycling power improvement in triathletes may reflect continued skill enhancement over the training period.
OBJECTIVE: The present study investigated the concurrent role of growth, maturation, and endurance training on neuromuscular function through a 9-month training period in adolescent triathletes.
METHODS: Thirty-eight 13- to 15-year-old males (23 triathletes [~6 h/week endurance training] and 15 untrained [<2 h/week endurance activity]) were evaluated before and after a 9-month triathlon training season. Maximal oxygen uptake (V̇O2max) and power at V̇O2max were assessed during incremental cycling. Knee extensor maximal voluntary isometric contraction torque (MVCISO) was measured and the voluntary activation level (VAL) was determined using the twitch interpolation technique. Knee extensor doublet peak torque (T100Hz) and normalized vastus lateralis (VL) electromyographic activity (EMG/M-wave) were also determined. VL and rectus femoris (RF) muscle architecture was assessed using ultrasonography.
RESULTS: Absolute V̇O2max increased similarly in both groups but power at V̇O2max only significantly increased in triathletes (+13.8%). MVCISO (+14.4%), VL (+4.4%), and RF (+15.8%) muscle thicknesses and RF pennation angle (+22.1%) increased over the 9-month period in both groups similarly (p < 0.01), although no changes were observed in T100Hz, VAL, or VL EMG/M-wave. No changes were detected in any neuromuscular variables, except for coactivation.
CONCLUSIONS: Endurance training did not induce detectible, additional neuromuscular adaptations. However, the training-specific cycling power improvement in triathletes may reflect continued skill enhancement over the training period.
摘要：
背景：神经肌肉功能被认为是成年期耐力表现的决定因素。然而,在青少年快速生长期内，耐力训练是否会引发进一步的神经肌肉适应，而不仅仅是生长和成熟的神经肌肉适应，还有待确定。
目的：本研究调查了生长的并发作用，成熟,青少年铁人三项运动员通过9个月的训练期对神经肌肉功能进行耐力训练。
方法：在9个月的铁人三项训练季节之前和之后，对38名13至15岁的男性（23名铁人三项运动员[〜6小时/周耐力训练]和15名未经训练的[<2小时/周耐力活动]）进行了评估。在递增循环过程中，评估了最大摄氧量（VFDAO2max）和VFDAO2max的功率。测量膝关节伸肌最大自愿性等距收缩力矩（MVCISO），并使用抽搐插值技术确定自愿性激活水平（VAL）。还确定了膝盖伸肌双峰扭矩（T100Hz）和归一化的股外侧肌（VL）肌电图活动（EMG/M波）。使用超声检查评估VL和股直肌（RF）肌肉结构。
结果：两组中绝对V♪O2max的增加相似，但在铁人三项运动员中V♪O2max的功率仅显著增加（+13.8%）。MVCISO（+14.4%），VL（+4.4%），和RF（+15.8%）肌肉厚度和RF悬挂角度（+22.1%）在9个月期间在两组相似（p<0.01），尽管在T100Hz中没有观察到变化，VAL,或VLEMG/M波。没有检测到任何神经肌肉变量的变化，除了共激活。
结论：耐力训练没有引起可检测的，额外的神经肌肉适应。然而,铁人三项运动员训练中特定自行车力量的提高可能反映了训练期间技能的持续提高。
目的：本研究调查了生长的并发作用，成熟,青少年铁人三项运动员通过9个月的训练期对神经肌肉功能进行耐力训练。
方法：在9个月的铁人三项训练季节之前和之后，对38名13至15岁的男性（23名铁人三项运动员[〜6小时/周耐力训练]和15名未经训练的[<2小时/周耐力活动]）进行了评估。在递增循环过程中，评估了最大摄氧量（VFDAO2max）和VFDAO2max的功率。测量膝关节伸肌最大自愿性等距收缩力矩（MVCISO），并使用抽搐插值技术确定自愿性激活水平（VAL）。还确定了膝盖伸肌双峰扭矩（T100Hz）和归一化的股外侧肌（VL）肌电图活动（EMG/M波）。使用超声检查评估VL和股直肌（RF）肌肉结构。
结果：两组中绝对V♪O2max的增加相似，但在铁人三项运动员中V♪O2max的功率仅显著增加（+13.8%）。MVCISO（+14.4%），VL（+4.4%），和RF（+15.8%）肌肉厚度和RF悬挂角度（+22.1%）在9个月期间在两组相似（p<0.01），尽管在T100Hz中没有观察到变化，VAL,或VLEMG/M波。没有检测到任何神经肌肉变量的变化，除了共激活。
结论：耐力训练没有引起可检测的，额外的神经肌肉适应。然而,铁人三项运动员训练中特定自行车力量的提高可能反映了训练期间技能的持续提高。
