• Journal of the Korea Convergence Society
• /
• v.11 no.10
• /
• pp.355-361
• /
• 2020

The squat is an exercise that can effectively improve the muscle strength of the lower body, which can be performed in a variety of places without restrictions on places including homes. However, injuries due to incorrect motion or excessive angles are frequently occurring. In this study, we developed a single sensor-based squat angle measurement system that can inform the squat angle according to the correct motion during the squat exercise. The sensor module, including the acceleration sensor and the gyro sensor, is attached to the user's thigh. The squat angle was calculated using the complementary filter complementing the pros and cons of acceleration and gyro sensor. It was found that the calculated squat angle showed the proper correlation compared to the squat angle measured by a goniometer, and the influence of the coefficient of the complementary filter on the accuracy was evaluated.

• Journal of the Korean Society of Physical Medicine
• /
• v.7 no.1
• /
• pp.87-94
• /
• 2012

Purpose : The purpose of this study was to examine the feasibility and efficiency of balance training program through an interactive video game regimen in people with chronic stroke. Methods : Thirty patients with chronic hemiparetic stroke were recruited. Participants were randomly assigned to either a control group (n=15) or an experimental group (n=15). The control group received the general physical therapy including of strengthening and balance exercise five times a week whereas the experimental group received a program of balance exercise with video game play based on virtual reality as well as the same typical physical therapy. The experimental group received 6 sessions for four weeks. Each session was given 5 minutes. An interactive computer game exercise regimen lasted 30 minutes without rest periods. Outcome measures for weight transfer to paretic side, non-paretic side and sit-squat-speed, sit-squat-length, sit-to-standspeed and sit-to-stand-area for the control group (n=15) and experimental group (n=15) before and after treatment were obtained by using the biorescure. Results: Outcomes demonstrated significant improvement in the experimental group compared with the control group in weight transfer to paretic side, non-paretic side and sit-squat-speed, sit-squat-length, sit-to-stand-speed. No significant training effect was showed in sit-to-stand-area between pretraining and post-training. Conclusion : An interactive computer game exercise based on task oriented approach for balance in chronic stroke were feasible. In other words, This regimen resulted in a greater improvement in dynamic balance for people with chronic stroke.

• Journal of Convergence for Information Technology
• /
• v.10 no.7
• /
• pp.160-167
• /
• 2020

This study was conducted to investigate the effects of modified wall squat exercise after sacro-iliac joint mobilization on balance in normal adults. The total number of subjects was 34, and 17 were randomly placed in the experimental group(EG) and 15 in the control group (CG). The subjects in the EG have conducted the 3 sets of modified wall squat exercise after sacro-iliac joint mobilization per day, 3 times a week for 6 weeks and CG did not conducted the intervention. Comparing the EG's balance pre-test and post-test this study, there was a statistical significance in WDI, CD, AC and AD. In this study, it was confirmed that modified wall squat exercise after sacro-iliac joint mobilization affects balance in normal adults.

• Physical Therapy Rehabilitation Science
• /
• v.10 no.3
• /
• pp.367-373
• /
• 2021

Objective: Short foot exercise(SFE) is frequently used to increase the medial longitudinal arch of the foot, as well as the intrinsic foot muscles. This studyinvestigated the effects of SFE onmuscular activity and the onset of contraction of the quadriceps femoris muscle during squats in healthypeople. It also aimed to compare and analyze the results with those of the general squat method and propose a more efficient squat method. Design: Cross-sectional study. Methods: This study compared 20 adults (male=10, female=10) who statisfied the inclusion criteria for the muscle activity and onset of the muscle contraction of the quadriceps femoris using surface EMG under two conditions: general squats and SFE squats. Results: Separate analyses and comparisons of the outcomes of the SFE squat and the general squat, showed a significant increase in the muscle activities of the rectus femoris and vastus medial muscles in both males and females (p<0.05). The onset of muscle contraction was significantly delayed for the vastus lateralis relative to that for the vastus medialis (p<0.05). However, it delayed significantly in females, but not in males. Conclusions: The SFE squats induced selective muscular activities of the rectus femoris and vastus medialis muscels and affected the onset of contraction of the vastus medialis and lateralis muscles.

• Physical Therapy Rehabilitation Science
• /
• v.10 no.4
• /
• pp.487-492
• /
• 2021

Objective: This study aimed to identify the effects of assuming two types of posture (standing and kneeling) during squat exercise on lower body muscle activity. Design: Cross-sectional study Methods: Twenty-five healthy adults (18 men and 7 women) were instructed to perform the squat exercises while assuming two types of posture (standing and kneeling). EMG (Electromyography) data (% maximum voluntary isometric contraction) were recorded three times from the rectus femoris (RF), gluteus maximus (GMax), gluteus medius (GMed) and biceps femoris (BF) of participant's dominant side and the mean values were analyzed. Results: During the squat exercise with all postures, there was statistically significant difference on rectus femoris, gluteus maximus, gluteus medius, and biceps femoris muscle activity (p<0.05). The results showed that, there was significantly greater rectus femoris, gluteus medius, and biceps femoris muscle activity in standing posture than in kneeling position (p<0.05). However, the gluteus maximus muscle activity was significantly greater with kneeling posture compared to standing posture (p<0.05). Conclusions: With standing posture, it is showed that rectus femoris, gluteus medius, and biceps femoris muscle activity was greater than kneeling position. While the gluteus maximus muscle activity with standing posture was less than with kneeling posture. Therefore, it is considered that this study can be used as a selective indicator of exercise posture for strengthening specific muscle or weakness caused by paralysis.

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

• Korean Journal of Applied Biomechanics
• /
• v.17 no.2
• /
• pp.113-121
• /
• 2007

The purpose of this study was to determine the effect of three different plates($0^{\circ}$, $10^{\circ$}, $20^{\circ}$)under heels on the lower limb muscles and erector spinae during squat exercise. Ten high school korean traditional wrestling players(age: $18.5{\pm}0.7$, weight: $1972.2{\pm}128.5N$, height: $177.8{\pm}6.0cm$, weight of barbell: $1004.5{\pm}132.4N$) performed squat exercise using three different tilting plates under heels at a cadence of 40beats/sec with 80% one repetition maximum load. Surface electrodes were placed on the participants' left and right erector spinae, and rectus femoris, vastus medialis, vastus lateralis, tibialis anterior, biceps femoris, medial gastrocnemius, and lateral gastrocnemius in the right lower extremity. One S-VHS camcorder(Panasonic AG456, 60fields/s) was placed 10m to the side of the participant. To synchronize the video and EMG data, a synchronization unit was used for this study. Average and Peak IEMG values were determined for each participant. For each variable, a one-way analysis of variance was used to determine whether there were significant differences among three different tilting plates under heels. When a significant difference was found in plates type, post hoc analyses were performed using the Tukey procedure. A confidence level of p<.05 was used to determine statistical significance. As a result of this study, maximum nEMG values of the tibialis anterior in $0^{\circ}$ plates was significantly higher than the corresponding values for the other plates during the knee extension. This increased activation in the tibialis anterior muscle indicates an increase in displacement of center of gravity of body. It is very likely that additional muscle activation are needed to stop the forward and backward movement. The results also showed that muscular activities of quadriceps femoris and erector spinae were decreased with increasing angle of plates. This suggests that increasing angle of plate may help to sustain the balance and posture of squat exercise. It is considered that very few significant differences were found among three different plates($0^{\circ}$, $10^{\circ}$, $20^{\circ}$) since elite players with much experience in squat exercise, were chosen as a participant of this study. In order to obtain meaningful results regarding the tilting angle of heel plates in squat exercise, kinetic and 3D kinematic analysis will be needed in the future study.

• Journal of the Korea Convergence Society
• /
• v.8 no.9
• /
• pp.365-372
• /
• 2017

Squat exercise is one of the important free weight exercises that can safely and effectively expect the athletic performance by establishing the rationale. Therefore, it is necessary to study the side effects caused by incorrect exercise, scientific countermeasures and to develop a exercise estimation model. It is effective and accurate to use a variety of assistive devices to calibrate athletic posture. The issues of the structural analysis for designing a foot plate for squat exercise is to model the behavior by the dynamic behavior. It should be consider that the center of gravity of each segmented body is different when the maximum load is applied. It is applied to complete system design through simulation method with kinematic dynamic, ground reaction force and load analysis for the free weight exercise equipment, VR device, and safety foot plate. In this paper, the authors propose the design method for the vertical load distribution applied in the design of the foot plate used for the squat exercise mechanism, and based on these results, design make the more safe and reliable free weight exercise equipment system.

• Physical Therapy Korea
• /
• v.22 no.3
• /
• pp.71-80
• /
• 2015

Hip muscle activation and strengthening exercise programs are often used to prevent and treat various lower extremity injuries. Common exercise programs include squat exercises. The purposes of this study were to investigate gluteus medius (GMED) and tensor fasciae latae (TFL) muscle activity, and to assess the GMED/TFL ratio during squat exercises involving different isometric hip contraction conditions. Different types of isometric hip contraction were standard squat without hip contraction, squats with isometric hip adduction, and squats with isometric hip abduction. Twenty (10 males and 10 females) healthy subjects ($23.7{\pm}2.8$ years old) were recruited. Subjects performed the squat exercises with the back supported by a wall and knees flexed to $60^{\circ}$. Surface electromyography (EMG) was used to measure GMED and TFL activity. One-way repeated analysis of variance was used to compare GMED and TFL muscle activity and the GMED/TFL ratio. GMED and TFL EMG activity was significantly higher during squats with isometric hip adduction and abduction compared with the standard squat without hip contraction (p<.05). Between the isometric hip adduction and abduction contraction conditions, only the TFL EMG activity was significantly higher during squats with isometric hip adduction than isometric hip abduction (p<.05). The GMED/TFL ratio was significantly higher during squats with isometric hip adduction than isometric hip abduction (p<.05). Squats with isometric hip adduction and abduction improved GMED and TFL muscle activity. Furthermore, the GMED/TFL ratio was higher during isometric hip adduction than isometric hip abduction. Our data indicate that squat exercises involving isometric hip adduction enhance GMED muscle activity.

• Physical Therapy Rehabilitation Science
• /
• v.8 no.2
• /
• pp.86-92
• /
• 2019

Objective: The purpose of this study was to compare the effects of performing squats and kneeling squats on trunk and lower extremity muscle activity in persons with stroke. Design: Cross-sectional study. Methods: Ten persons with stroke (3 male and 7 female) were recruited. The subjects were instructed to randomly perform the 4 different squat conditions: squat with 30 degrees of knee flexion, squat with 60 degrees of knee flexion, squat with 90 degree of knee flexion, and the kneeling squat. During the squat performance, surface electromyograms (sEMG) was used to assess muscle activity of the erector spinae (ES), gluteus maximus (Gmax), gluteus medius (Gmed), and biceps femoris (BF) muscles. Results: Muscle activation of the ES and BF were significantly increased with the kneeling squats compared to the general squats with 30 degrees and 60 degrees of knee flexion (p<0.05), and muscle activation of the Gmax and Gmed were significantly increased with the kneeling squats compared to all other squat conditions (p<0.05). Conclusions: The results suggest that the kneeling squat is an effective exercise to strengthen the proximal muscles of the lower extremities. Rather than applying a difficult general squat to the stroke population, the kneeling squat may be applied as a safer method for training the proximal muscles.