• The Journal of Korean Physical Therapy
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• v.34 no.2
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• pp.63-67
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• 2022

Purpose: The purpose of this study was to investigate the effect of assistance tools such as gym balls, wedges, and straps on lower extremity muscle activity and the increase in the range of motion made possible by the use of these tools. The subjects were divided into two groups: a group capable of deep-squatting (PS) and the second finding it impossible or having difficulty in performing such squats (IS). Methods: Twenty-three subjects participated in this study. Surface electromyography was used to measure the muscle activation of the rectus femoris (RF), vastus medialis (VM), and tibialis anterior (TA) muscles during deep squats, normal squats (NS), gym ball squats (GS), wedge squats (WS), and strap squats (SS). A motion analysis system was used to measure the range of motion of the knee joint during each of these exercises. Results: There was a significant difference in the RF muscle activity between the possible squat (PS) and the impossible squat (IS) groups in the GS, and there were significant differences in the RF and TA muscle activity between the groups in the WS. Both the PS group and the IS group showed a significant difference in the TA muscle activity depending on the tool used. There were also significant differences in the range of motion of the knee joints between the intervention methods using NS and those using the tools. Conclusion: In both groups, the muscle activity of the TA muscles was lower when GS, WS, and SS were performed compared to NS. In addition, compared to NS, the range of motion of the knee joint increased when the three tools were used. This study shows that the activity of the RF, VM, and TA muscles decreased and the range of motion of the knee joint increased during deep squats for both the PS and IS groups when tools were used.

• Journal of Korean Physical Therapy Science
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• v.31 no.3
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• pp.89-99
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• 2024

Background: Squats are well-known for their effectiveness in strengthening the quadriceps femoris muscle. Flexibility and stability of the ankle joint are critical factors in performing squats correctly. Ankle instability can lead to injuries owing to compensatory actions. The role of the soleus muscle in maintaining ankle balance is crucial to minimize the risk of injury. Moreover, squats on unstable surfaces have gained attention for their potential to enhance balance and stability, which in turn helps prevent injuries. Therefore, this study aims to investigate the correlation between the soleus and quadriceps femoris muscles during squat exercises on various support surfaces. Design: Simple regression analysis Methods: Participants performed three different types of squats. Prior to commencing the exercises, we conducted electromyography (EMG) measurements to assess the activity of both the soleus and quadriceps femoris muscles. The order of the exercise execution was randomized. The squats were performed in a Full Squat format, and a one-minute rest was provided between each exercise type. Results: Our analysis of the results revealed significant differences in the activation levels of the soleus and quadriceps femoris across different squat types (p<.05). The regression analysis revealed an inverse relationship between the activity levels of the soleus and quadriceps femoris. Specifically, the quadriceps femoris exhibited the highest activation during squats using a wedge, while its activation was lowest during squats using the TOGU. In contrast, the soleus muscle demonstrated its highest activation during squats using the TOGU. Conclusion: Compared to traditional floor squats, the disparities in soleus and quadriceps femoris muscle activation observed during Wedge or TOGU squats can be attributed to the influence of ankle stability and balance. As the surface instability increased during squats, the soleus muscle's activity increased while the activation of the quadriceps femoris muscle decreased. These findings suggest that heightened soleus activation on unstable surfaces can significantly impact the activation of the quadriceps femoris muscle during squat exercises.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.4
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• pp.291-297
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• 2014

The purpose of this study was to investigate the change of the electromyographic activity in vastus medialis oblique (VMO) and vastus lateralis (VL), also vastus medialis oblique/vastus lateralis ratios after wearing wedged flated or 5cm heel shoes. The subjects were 30 healthy women who randomly assigned to two group, divided by flated or 5cm heel group. They were asked to perform squat exercise in two postures using medial and lateral wedged shoes. In two groups, EMG activity of VMO and VL was significant difference between the flated heel and 5cm heel (p<.01). This study showed that 5cm heel could selectively more active VMO than flated heel. It should be considered the heel height as the parameter when the patient with lower extremity problem undergo rehabilitation exercise or design of orthoses for the selective muscle activity of knee pain or knee instability.