Arm cycling is commonly used in rehabilitation settings for individuals with motor impairments in an attempt to facilitate neural plasticity, potentially leading to enhanced motor function in the affected limb(s). Studies examining the neural control of arm cycling, however, typically cycle using a set cadence and power output. Given the importance of motor output intensity, typically represented by the amplitude of electromyographic (EMG) activity, on neural excitability, surprisingly little is known about how arm muscle activity is modulated using relative workloads. Thus, the objective of this study was to characterize arm muscle activity during arm cycling at different relative workloads. Participants (n = 11) first completed a 10-second maximal arm ergometry sprint to determine peak power output (PPO) followed by 11 randomized trials of 20-second arm cycling bouts ranging from 5–50% of PPO (5% increments) and a standard 25 W workload. All submaximal trials were completed at 60 rpm. Integrated EMG amplitude (iEMG) was assessed from the biceps brachii, brachioradialis, triceps brachii, flexor carpi radialis, extensor carpi radialis and anterior deltoid of the dominant arm. Arm cycling was separated into two phases, flexion and extension, relative to the elbow joint for all comparisons. As expected, iEMG amplitude increased during both phases of cycling for all muscles examined. With the exception of the triceps brachii and extensor carpi radialis, iEMG amplitudes differed between the flexion and extension phases. Finally, there was a linear relationship between iEMG amplitude and the %PPO for all muscles during both elbow flexion and extension.

中文翻译：

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在手臂循环的屈曲和伸展阶段肌肉活动的变化作为功率输出的影响是肌肉特定的

手臂循环通常用于有运动障碍的个体的康复环境中，以促进神经可塑性，可能导致受影响肢体的运动功能增强。然而，检查手臂骑行的神经控制的研究通常使用设定的节奏和功率输出进行循环。考虑到运动输出强度（通常由肌电图 (EMG) 活动的幅度表示）对神经兴奋性的重要性，令人惊讶的是，关于如何使用相对工作负荷调节手臂肌肉活动知之甚少。因此，本研究的目的是表征在不同相对工作负荷下进行手臂骑行期间的手臂肌肉活动。参与者 (n = 11) 首先完成了 10 秒最大手臂测力冲刺以确定峰值功率输出 (PPO)，然后进行 11 项随机试验，进行 20 秒手臂循环，范围为 PPO 的 5-50%（增量为 5%）和标准的 25 W 工作负载。所有次极量试验均在 60 rpm 下完成。从肱二头肌、肱桡肌、肱三头肌、桡侧腕屈肌、桡侧腕伸肌和优势臂的前三角肌评估综合 EMG 振幅 (iEMG)。对于所有比较，相对于肘关节，手臂循环分为两个阶段，屈曲和伸展。正如预期的那样，对于所有检查的肌肉，iEMG 振幅在骑自行车的两个阶段都增加了。除了肱三头肌和桡侧腕伸肌，iEMG 振幅在屈曲和伸展阶段之间不同。最后，