Makino Akitoshi, Yamaguchi Keiichi, Sumi Daichi, Ichikawa Masaru, Ohno Masumi, Nagano Akinori, Goto Kazushige
Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan.
Front Sports Act Living. 2023 Feb 17;4:1055302. doi: 10.3389/fspor.2022.1055302. eCollection 2022.
Physically active status is an important contributor to individual health. Walking is regarded as commonly accepted exercise for exercise promotion. Particularly, interval fast walking (FW), consisting of alternating between fast and slow walking speeds, has gained popularity from practical viewpoints. Although previous studies have determined the short- and long-term effects of FW programs on endurance capacity and cardiovascular variables, factors affecting these outcomes have not been clarified. In addition to physiological variables, understanding of mechanical variables and muscle activity during FW would be a help to understand characteristics of FW. In the present study, we compared the ground reaction force (GRF) and lower limb muscle activity between fast walking (FW) and running at equivalent speeds.
Eight healthy men performed slow walking (45% of the maximum walking speed; SW, 3.9 ± 0.2 km/h), FW (85% of the maximum walking speed, 7.4 ± 0.4 km/h), and running at equivalent speeds (Run) for 4 min each. GRF and average muscle activity (aEMG) were evaluated during the contact, braking, and propulsive phases. Muscle activities were determined for seven lower limb muscles: gluteus maximus (GM), biceps femoris (BF), rectus femoris (RF), vastus lateralis (VL), gastrocnemius medialis (MG), soleus (SOL), and tibialis anterior (TA).
The anteroposterior GRF was greater in FW than in Run during the propulsive phase (p < 0.001), whereas the impact load (peak and average vertical GRF) was lower in FW than in Run (p < 0.001). In the braking phase, lower leg muscle aEMGs were higher during Run than during SW and FW (p < 0.001). However, in the propulsive phase, soleus muscle activity was greater during FW than during Run (p < 0.001). aEMG of tibialis anterior was higher during FW than during SW and Run in the contact phase (p < 0.001). No significant difference between FW and Run was observed for HR and RPE.
These results suggest that the average muscle activities of lower limbs (e.g., gluteus maximus, rectus femoris, and soleus) during the contact phase were comparable between FW and running, however, the activity patterns of lower limb muscles differed between FW and running, even at equivalent speeds. During running, muscles were mainly activated in the braking phase related to impact. In contrast, during FW, soleus muscle activity during the propulsive phase was increased. Although cardiopulmonary response was not different between FW and running, exercise using FW might be useful for health promotion among individuals who cannot exercise at high-intensity.
身体活动状态是个体健康的重要影响因素。步行被视为促进锻炼的普遍认可的运动方式。特别是，间歇快走（FW），即快速和慢速步行速度交替进行，从实际角度来看越来越受欢迎。尽管先前的研究已经确定了FW计划对耐力和心血管变量的短期和长期影响，但影响这些结果的因素尚未明确。除了生理变量外，了解FW过程中的力学变量和肌肉活动将有助于理解FW的特征。在本研究中，我们比较了快走（FW）和相同速度跑步时的地面反作用力（GRF）和下肢肌肉活动。
八名健康男性分别进行慢速步行（最大步行速度的45%；SW，3.9±0.2千米/小时）、FW（最大步行速度的85%，7.4±0.4千米/小时）和相同速度跑步（Run），各持续4分钟。在接触、制动和推进阶段评估GRF和平均肌肉活动（aEMG）。测定了七块下肢肌肉的活动：臀大肌（GM）、股二头肌（BF）、股直肌（RF）、股外侧肌（VL）、腓肠肌内侧头（MG）、比目鱼肌（SOL）和胫骨前肌（TA）。
在推进阶段，FW的前后GRF大于Run（p<0.001），而FW的冲击负荷（峰值和平均垂直GRF）低于Run（p<0.001）。在制动阶段，Run期间小腿肌肉的aEMG高于SW和FW期间（p<0.001）。然而，在推进阶段，FW期间比目鱼肌的活动大于Run期间（p<0.001）。在接触阶段，FW期间胫骨前肌的aEMG高于SW和Run期间（p<0.001）。FW和Run在心率（HR）和主观用力程度（RPE）方面未观察到显著差异。
这些结果表明，在接触阶段，FW和跑步时下肢的平均肌肉活动（如臀大肌、股直肌和比目鱼肌）相当，然而，即使在相同速度下，FW和跑步时下肢肌肉的活动模式也有所不同。在跑步过程中，肌肉主要在与冲击相关的制动阶段被激活。相比之下，在FW过程中，推进阶段比目鱼肌的活动增加。尽管FW和跑步之间的心肺反应没有差异，但对于无法进行高强度运动的个体，使用FW进行锻炼可能有助于促进健康。
