Effect of circulatory system response to motor control in one-sided contractions

The purpose of this study was to clarify the effect one-sided skeletal muscle contraction has on the circulatory system, spinal α-motoneuron excitability, and somatosensory-system-evoked potential.

Nine healthy males maintained tension at 10, 20, and 30% of maximal voluntary contraction in static gripping in right hand. Heart rate, ln high frequency (HF), blood pressure (BP), F-wave, and somatosensory-evoked potential (SEP) were recorded during gripping task. BP, F-wave and SEP were recorded from left hand (contralateral side from contracting side).

There were significant main effects of contractions strength on heart rate (0%: 68.2 ± 6.8 bpm, 10%: 67.6 ± 7.4 bpm, 20%: 69.7 ± 8.5 bpm, 30%: 73.7 ± 9.3 bpm, F_3.24=9.18, P < 0.01), systolic BP (0%: 127.7 ± 15 mmHg, 10%: 136.2 ± 13.5 mmHg, 20%: 136.2 ± 13.5 mmHg, 30%: 140.0 ± 17.1 mmHg, F_3.24=23.93, P < 0.01), diastolic BP (0%: 69.3 ± 8.5 mmHg, 10%: 76.9 ± 11.1 mmHg, 20%: 79.9 ± 12.5 mmHg, 30%: 86.2 ± 14 mmHg, F_3.24=17.09, P < 0.01), and F-wave appearance rate (0%: 29.7 ± 15.6%, 10%: 39.3 ± 20.5%, 20%: 47.5 ± 22.9%, 30%: 55.2 ± 21.8%, F_3.24=14.04, P < 0.01). For the ln HF (0%: 5.9 ± 0.6, 10%: 6.3 ± 0.9, 20%: 6.3 ± 1.3, 30%: 6.0 ± 1.0, F_3.24=2.43, P = 0.08), F-wave latency (0%: 29.6 ± 1.7 ms, 10%: 26.9 ± 2.1 ms, 20%: 26.5 ± 3.6 ms, 30%: 26.9 ± 2.3 ms, F_3.24=0.11, P = 0.96), F-wave amplitude (0%: 2.0 ± 0.9%, 10%: 2.2 ± 0.9%, 20%: 2.3 ± 0.7%, 30%: 2.8 ± 1.1%, F_3.24=2.80, P = 0.06), and N20 amplitude (0%: 3.9 ± 1.7 µV, 10%: 3.7 ± 1.7 µV, 20%: 3.9 ± 1.7 µV, 30%: 3.9 ± 1.8 µV, F_3.24=0.61, P = 0.62), between the conditions. We conclude that regulation of the circulatory system and motor system has a limited effect on sensory input.