• Journal of the Korean Society of Physical Medicine
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• v.8 no.4
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• pp.647-653
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• 2013

PURPOSE: The purpose of this study was to compare the lower extremities muscle activation between squatting exercise with gym ball and wall for improving muscle strengthening in lower extremities. METHODS: Participants were 21 university students (males 10, females 11) who didn't have any problem with orthopedic surgery. Participants performed squatting exercise with gym ball and wall. Squatting exercise with gym ball were performed using by gym ball behind back, and the gym ball were fixed in back and wall. We asked participants to push back the gym ball slightly to prevent fall of ball. Wall squatting exercise, we ask participants to contact their back in wall slightly in order to prevent trunk flexion during performed squatting exercise. Each squatting exercise had performed until knee joint were flexed at 60 degree, and maintained five seconds. We collected data from E.M.G of Biceps femoris, Gastrocnemius, Vastus medialis and lateralis, Tibialis anterior of lower extremity in isometric phase of knee joint angle 60 degree of each squatting exercise. We analysed data using by ANOVA and independent t-test of SPSS PC ver.20.0 in order to compare the muscle activation between squatting exercise with gym ball and wall. RESULT: All of lower extremities muscle activation showed more higher value in squatting exercise with gym ball than squatting exercise with wall, especially there was significantly difference of muscle activation in vastus medialis, tibialis anterior between squatting exercise with gymball and with wall. CONCLUSION: On comprehensively considering the results of the present study, we suggested that squatting exercise with gym ball was more effective method improving lower extremity muscle strengthening.

• Journal of Korean Physical Therapy Science
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• v.22 no.1
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• pp.43-48
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• 2015

Background : The purpose of this study was find out more effective method for improving muscle strengthening in lower extremities according squatting exercise method among knee joint angle 45, 60, 90 degree and between gym ball behind back and wall. Methods : Participants were 21 university students(males 10, females 11) who didn't have any problem with orthopedic surgery. We divided participants to two groups with gym ball group and wall group. Gym ball group were performance squatting exercise with gym ball behind back. Each group had performance squatting exercise according knee joint angle 45, 60, 90 degree. We collected data from E.M.G of Biceps femoris, Gastrocnemius, Vastus medialis and lateralis, Tibialis anterior in lower extremity according knee joint angle 45, 60, 90 degree of each groups. We analyzed data using by ANOVA and ANCOVA of SPSS PC ver. 12.0 in order to determine more effective method according various squatting exercise. Results : Each groups show significantly difference value of biceps femoris, vastus lateralis and medialis, tibialis anterior, gastrocnemius lateralis and medialis among knee joint angle 45, 60, 90 degree. But there was no significantly difference value between gym ball group and wall group according knee joint angle. Conclusions : We suggested that squatting exercise with gym ball was more effective method improving lower extremity muscle strengthening, and changing knee joint angle was more effective compared than continued knee joint angle.

• The Journal of Korean Physical Therapy
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• v.24 no.3
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• pp.216-222
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• 2012

Purpose: Weight-bearing exercise is a type of physical exercise that is widely performed for rehabilitation after acquiring nervous-system diseases or sports-related injuries. It is one of the most commonly prescribed rehabilitation programs for strengthing of the lower extremities. Weight-bearing exercise is important for the conduct of such activity of daily living (ADLs) as walking, and up and down the stairs. The purpose of this study was to investigate the muscle activities during one-leg standing and one-leg squatting, the two most representative weight-bearing exercises. Methods: A total of 43 elderly (60~70 years old) males who could perform weight-bearing exercises were included in the study. During the one-leg standing and one-leg squatting, the electromyographic (EMG) signals were quantified as maximum voluntary isometric contraction (%MVIC) using surface EMG, and then the muscle activities of the lower extremities during the two exercises were compared. For statistical analysis, an independent sample t-test and one-way ANOVA were performed. Results: The results of the study are as follows: (1) in the one-leg standing, the activity of the gluteus medius was the greatest among the vastus medialis, vastus lateralis, bicep femoris, (2) in the one-leg squatting, the activity of the vastus medialis was the greatest; and (3) the activity was greater in the one-leg squatting than in the single-leg standing exercise. Conclusion: The one-leg standing and squatting exercises are suitable for strengthening the muscles for the prevention of and recovery from lower-extremity injury, and for functional ADL in elderly people. In addition, dynamic exercise was shown to be more effective than static exercise for strengthening the muscles.

• Journal of International Academy of Physical Therapy Research
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• v.9 no.1
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• pp.1435-1441
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• 2018

The main focus of this study was to investigate effects of lumbar central posteroanterior (PA) mobilization on isometric knee extension (IKE) ability and patellar tendon reflex amplitude (PTRA) in healthy university students. University students aged 19-26 (male; 10, female; 10) without any neurological disorders participated voluntarily and excluded the subjects with abnormal reflexes. The participation had an average body mass of $64.25{\pm}13.52kg$, an average height of $1.66{\pm}0.08m$, and an average Body Mass Index (BMI) of $23.07{\pm}3.21$. Every student was randomly assigned to be received squatting exercise and PA mobilization sequentially with 5 days of wash out period. IKE and PTRA were not significantly different between the two groups after the intervention. All the outcome measures were arranged into two data groups; PA mobilization and squatting exercise data group. In the PA mobilization data group, IKE and PTRA significantly increased after the intervention, however, these aspects were decreased in the squatting exercise group. These findings suggest that IKE and PTRA increase immediately after PA mobilization, therefore PA mobilization could be a valuable topic for controlled clinical trials.

• International Journal of CAD/CAM
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• v.12 no.1
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• pp.1-8
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• 2012

This study analyzes the characteristics of two different kinds of squat exercise through physical experiments and a computer simulation, i.e. one with a free weight and the other with a Smith machine are studied. This study also proposes a new design for the Smith machine, which has both the advantages of each type based on the results of the analysis. The muscle force and level of stimulation of the lower extremities during squatting were calculated by running an inverse dynamics analysis program on a musculoskeletal model together with the measured motion data. The calculated results were verified by comparing with the measured EMG data. The analysis showed that squatting using free weight is more effective than squatting using the Smith machine. Meanwhile, in order to design an improved Smith machine, which is the final goal of this study, the trajectory of the barbell of the subjects during free weight squatting was measured on the sagittal plane. The measurement showed that the average slope of the trajectory of the barbell is tilted backward by $10.7^{\circ}$. Based on this measurement, this study proposes a tilted design for an improved Smith machine.

• Physical Therapy Korea
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• v.23 no.4
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• pp.9-15
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• 2016

Background: Squatting is one of the best functional exercises to strengthen the quadriceps muscle in independent gait and activities of daily living. Although the use of a gym ball during squat exercise is the most common way of strengthening the vastus medialis oblique (VMO) muscle, published data on this subject are limited. Objects: The purpose of this study was to compare the sequential muscle activation of the VMO and vastus lateralis (VL) muscles during squat exercise using a gym ball at different knee flexion angles. Methods: Forty healthy adults were randomly divided into experimental (squat exercise using a gym ball) and control (squat exercise alone) groups, in which squats were performed at $45^{\circ}$ and $90^{\circ}$ knee flexion. Electromyographic (EMG) activity data were collected over 10 seconds under the 2 angles of knee flexion ($45^{\circ}$ and $90^{\circ}$). Results: There was significant group and time interaction effect for VMO and VL muscle activation at $45^{\circ}$ knee flexion. This was similarly demonstrated at $90^{\circ}$ knee flexion. No significant group main effect and time main effect for VMO and VL muscle activation were noted at $45^{\circ}$ knee flexion, respectively. In contrast, there was significant group main effect and time main effect for VMO and VL muscle activation at $90^{\circ}$ knee flexion. These significant differences were demonstrated through two-way analysis of variance over repeated measurements, suggesting that the EMG activity of the VMO muscle during squatting with a gym ball showed remarkable improvement compared to that of the VL muscle. Conclusion: This research suggests that squat exercise using a gym ball may be more beneficial in improving the activity of VMO than of the VL muscle at both $45^{\circ}$ and $90^{\circ}$ of knee flexion, respectively. We highly recommend squat exercises with a gym ball for selective strengthening of the VMO muscle in knee rehabilitation.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.2
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• pp.1-8
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• 2021

PURPOSE: This study examined the effects of changes in the head direction (forward, upward 10° and downward 10°) on the quadriceps, center of pressure (COP), and foot pressure during squat exercises. The aim was to determine if the head direction could better activate the quadriceps muscle and provide a safer and stable squat posture during squat exercise. METHODS: Fifteen healthy college students were asked to stand on a Zebris, and three electrodes for sEMG were attached to their vastus medialis oblique (VMO), vastus lateralis (VL), and rectus femoris (RF) muscles. The participants then performed squatting exercises under three head directions (forward, upward 10°, and downward 10°). Surface electrodes were then used to record the EMG data during exercise. The Zebris FDM-SX was used to measure the foot pressure and COP of the participants. RESULTS: In squat exercise, the upward head direction group showed significantly higher VL activation than the downward head direction group (p < .05). The upward head direction group showed a significant backward change in the deviation of the COP than the downward and forward groups (p < .05). The upward head direction group showed a significant decrease in forefoot pressure than the downward and forward groups (p < .05) and an increase in the hindfoot pressure compared to the downward and forward groups (p < .05). CONCLUSION: The head direction upward in squat exercise has a positive effect on the quadriceps.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.1
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• pp.23-31
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• 2021

PURPOSE: This study was conducted to identify the effects of altering foot position on quadriceps femoris including vastus medialis obliques (VMO), vastus lateralis (VL) and rectus femoris (RF) activation during wall squat exercises. METHODS: All subjects (n = 15) were selected and randomly performed three kinds of wall squats: 1) GWS (General Wall Squat), 2) WSS1/4 (Wall Squat Short 1/4), and 3) WSS1/2 (Wall Squat Short 1/2). Each subject completed all three kinds of wall squatting exercises at three different times and recorded the muscle activity data of vastus medialis obliques, vastus lateralis and rectus femoris. RESULTS: Compared with GWS exercise, VMO and RF muscle activity significantly increased under WSS1/2 exercise (p < .05), while only RF muscle activity significantly increased under WSS1/4 exercise (p < .05). CONCLUSION: The results of the present study indicate that moving the foot toward the wall during wall squats has a positive effect on quadriceps activation. The exercise of wall squat short can not only be used as the lower limb muscle strengthening training for normal people, but also as the recovery training for patellofemoral pain syndrome patients in the rehabilitation stage. Besides, Anterior cruciate ligament patients can also try this exercise according to the advice of doctors and therapists.

• The Journal of Korean Physical Therapy
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• v.18 no.2
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• pp.35-45
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• 2006

Purpose: This study was to investigate the effect of isometric exercise and active stretching on joint function in patient with osteoarthritis. Methods: 30(M=1, F=29) subjects with osteoarthritis were divided in three groups: control group, quadriceps isometric exercise group, and hamstring active stretching group. After 6 weeks treatment, ROM(range of motion) and LSS(lysholm scoring scale) were measured. Results: There was a significant increase in knee flexion, extension in post-treat of quadriceps isometric exercise group and hamstring active stretching group(p<0.05). There was a significant increase in LSS in post-treat of quadriceps isometric exercise group and hamstring active stretching group(p<0.05). Conclusion: This study shows that both the active stretching exercise and the quadriceps isometric exercise effectively promote the range of knee extensions for osteoarthritis patients. Also, as measuring the ROM of knee flexion and extension by exercise methods, there is significant increase from knee flexion and extension in both hamstring stretching exercise group and quadriceps isometric exercise group. The increase of the range of knee is more effective in the exercise of knee extension with hamstring stretching exercise groups. And it is found that there are some difference between the experimental group and controlled group in statistics. As it is concerned with the function of knee extension, supporting and squatting are more effective to promote the both knee extension and flexion in its range. Therefore, this shows that the hamstring stretching exercise is required in general with enforcing the quadriceps at a sickbed in the present.

• PNF and Movement
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• v.15 no.1
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• pp.27-33
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• 2017

Purpose: This study examined the effects of upper- and lower-limb coordinated exercise with proprioceptive neuromuscular facilitation (PNF) on stroke patients' recovery of their balancing and walking abilities. Methods: This study was conducted with 30 patients aged at least 60 years and diagnosed with stroke. The patients were randomly assigned to either a PNF upper- and lower-limb coordinated exercise group of 15 patients or an aero-step balance exercise group of 15 patients. To test the subjects' balancing and walking abilities, balancing ability tests and 10-m walking speed tests were conducted before and after the interventions. The patients performed their respective exercises for 30 minutes per session, three times per week for four weeks. The PNF exercise group performed six stages of exercise consisting of a combination of PNF patterns such as sprinting, skating, and striking. The six stages (right striking, right skating, right sprinting, left striking, left skating, and left sprinting) were performed continuously with a rest period of 1 min. after training for 4 min. The exercises for the aero-step balance group consisted of balancing in a two-leg standing position, weight shifting in a two-leg standing position, one-leg standing, squat exercises, marching in place, and squatting on an aero step. Results: The PNF exercise group showed significant improvements in their balancing ability evaluations compared to the aero-step balance group and also showed significant improvements in their 10-m walking speed tests. Conclusion: Based on the results of this study, PNF upper- and lower-limb coordinated exercise resulted in clinical improvements of stroke patients' balancing and walking abilities. Therefore, this type of exercise is recommended as a clinical intervention for the recovery of stroke patients' lower-limb function. Future studies should be conducted with longer intervention periods and more subjects to generalize the study results.