Trunk Muscle Activity During Seated Strength Exercise With Resistance Wheeled Training Equipment.

Objective: This study aimed to measure muscle activity during seated trunk strength training using resistance-wheeled training equipment at different resistance levels. Methods: The participants were 19 healthy males. Resistance-wheeled training equipment, such as the small vehicle used in this study, had a mechanical braking function that locked the wheels and unlocked the brakes while only pressing downward with a constant force. The subjects moved the equipment forward and backward on a desk with an unlocked brake status. The participants performed under 3 conditions; (1) unlocked with no force, (2) unlocked with low force, and (3) unlocked with high force. Results: Muscle activity increased significantly with increasing locked strength in the deltoid posterior, internal and external oblique, rectus abdominis, erector spinae thorax, and lumbar muscles. Some muscles reached over 50% of the maximum voluntary contraction when unlocked with a high force. Conclusion: The muscle activity measured during trunk training that exceeded 50% of the maximum voluntary activation level corresponds to be sufficiently high for strength training and the activity level required for muscle hypertrophy. We believe that this research equipment may be a useful seated trunk strength training device.