• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.9
• /
• pp.753-760
• /
• 2016

This study was undertaken to develop a bed-type cycling system of lower limbs for rehabilitation. This system consists of two modes of cycling: active and passive. Different velocity and loads are provided for improving the muscle function recovery and increasing the muscular strength. To analyze the muscle activity pattern, we measured muscular activity of lower limbs in the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), medial gastrocnemius (MG), and soleus (SOL), while cycling in the supine position, and based on the pedaling direction. A total of 18 young and 23 elderly, healthy subjects participated in this study. Muscle activity of MG muscles was significantly different in the two age groups. This study could provide the reference data to develop cycling exercises for lower limbs during rehabilitation of the elderly patients.

• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.12
• /
• pp.1434-1440
• /
• 2011

In this paper, we assessed muscular activities of lower limbs and foot pressure for car and bus drivers according to operating three electronic pedals that we developed. To analyze drivers' physical exhaustion, muscular fatigue of lower limbs was evaluated. Eleven car drivers and six urban bus drivers were participated in this experiment. The virtual driving system was used for the real driving environment. The virtual driving system was comprised of a spring seat, a steering wheel, pedals (clutch, excel and brake pedals), a manual transmission and a virtual driving simulation. For the real vibration like situation on the road, six degree of freedom motion base system was used. Measured muscles were rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA) and gastrocnemius (Gn) muscles. For the quantitative muscular activities, integrated electromyography (IEMG) was analyzed. Muscular fatigues also were analyzed through the analysis of the median frequency. In addition, foot pressures were analyzed and compared through the peak and averaged pressure during the operating three developed electronic pedals. The experiments are conducted with total 17 drivers, 11 general public and 6 drivers. As a result of the analysis, electromyogram and fatigue analysis through intermediate frequency reduction for pedal-1 more efficient than other pedals. And foot pressure also was decreased. Consequently, we suggested the most efficient pedal and method to minimize the amount of cumulative fatigue.

• PNF and Movement
• /
• v.19 no.1
• /
• pp.79-86
• /
• 2021

Purpose: The purpose of this study was to investigate muscle activity according to knee flexion angle during single-limb-deadlift exercises. Methods: In total, 26 healthy volunteers participated. The single-limb-deadlift consisted of 0˚, 15˚, and 30˚ knee joint bending. The electromyography data were collected from the semitendinosus (SM), the biceps femoris (BF), the rectus femoris (RF), the vastus lateralis (VL), and the vastus medialis (VM). In addition, hamstrings and quadriceps (HQ) ratio was measured during the single-limb-deadlift using electromyography. Results: During the single-limb-deadlift, RF, VL, and VM were significantly higher at 30˚ bending angles compared to muscle activity of 0˚ and 15˚ knee-joint bending. The HQ ratio had significant differences in all three knee joint bending angles. In particular, the single-limb-deadlift carried out to a 30˚ knee-joint bend showed the closest value to 1. Conclusion: The most balanced coactivation ratios were observed during a single-limb-deadlift to a 30˚ knee-joint bend angle. A single-limb-deadlift at a knee-bend angle of less than 30˚ could be used as an exercise to prevent ACL injury. It could also be used for post-injury rehabilitation programs by increasing knee-joint stability.

• The Journal of Korean Physical Therapy
• /
• v.33 no.2
• /
• pp.53-61
• /
• 2021

Purpose: This study examined the impacts of action observational physical training related to stair walking on the stair walking ability and self-efficacy of chronic stroke patients. Methods: This study was conducted on 24 chronic stroke patients, who were assigned randomly to an action observational physical training group (12 persons) and a landscape observation physical training group (12 persons). To the action-observational physical training group, five videos related to stair walking were presented, and after observing them, physical training was carried out. The landscape observation physical training group observed the videos consisting of landscape, where there were no humans and animals, and then underwent physical training. This study measured the rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius to examine the muscle activity of the lower limb. A timed up and go and step test was performed to examine the balance ability, and a timed stair test was conducted to examine their stair walking ability. A self-efficacy scale was measured to examine the degree of their confidence of performing stair walking. The assessment was conducted three times in total: pre-, post-, and follow-up surveys. Results: As a result of this study, the action observational physical training group significant improvement after the intervention than in the landscape observation physical training group. Moreover, the follow-up study four weeks after the intervention showed significant improvements in the action observational physical training group (p<0.05). Conclusion: These results show that the action observational physical training had a positive impact on the stair walking ability and self-efficacy of chronic stroke patients.

• Journal of the Korean Society of Physical Medicine
• /
• v.13 no.4
• /
• pp.131-138
• /
• 2018

PURPOSE: This study was conducted to compare the muscle activity of the proximal muscles of the lower limb according to the distance between the front and rear foot during lunge and to determine the most effective foot position for activation of the proximal muscle in the limb. METHODS: A total of 49 young adults were enrolled in this study. All subjects performed lunge by positioning the big toe of the back foot and the heel of the front foot at intervals of 40%, 60%, and 80% of the subject's own leg length. Muscle activity of the vastus medialis oblique, rectus femoris (RF), vastus lateralis oblique (VLO), gluteus medius, biceps femoris, and semitendinosus (ST) was then measured during three intervals of lunge operation. Each operation was measured three times for 10 seconds each, after which the average value was calculated and analyzed. RESULTS: There were significant differences in muscle activities of RF, VLO, and ST among the three intervals of the foot (p<.05). Post hoc, comparisons revealed lunge at 40% intervals resulted in higher RF and VLO activity than at 60% and 80% intervals (p<.05). In the semitendinosus muscle, 80% leg length intervals showed higher muscle activity than 40% (p<.05). CONCLUSION: Strengthening of the proximal muscles of the lower extremities during lunge exercise is considered to be most effective when placing the fore- and rear foot at intervals corresponding to 40% of the leg length.

• Journal of the Korean Society of Physical Medicine
• /
• v.13 no.4
• /
• pp.139-148
• /
• 2018

PURPOSE: This study compared the effects of indoor and outdoor environmental changes on the activity of the major lower limb muscles and walking factors in people 40-50 years and those aged older than 70 years. METHODS: Ten middle-aged people in their forties (age:$44.2{\pm}2.7$, BMI:$21.8{\pm}1.8$) and 10 elderly aged more than 70 years (age:$76.4{\pm}5.9$, BMI:$22.2{\pm}1.9$) with a normal walking ability were included. The participants walked 100 m both indoors and outdoors at their own speed. Using a 3D motion analyzer and EMG, the walking speed, angle of the ankle and activity changes of the lower limb muscles were compared. RESULTS: Significant differences in walking speed and peak-plantar flexion angle were observed between the two groups (p<.05). The muscular activity of the gastrocnemius muscle (GCM) was significantly different outdoors in the swing phase between the two groups (p<.05). In the people aged in their forties, the muscular activity of the rectus femoris (RF) was significantly higher outdoors than indoors (p<.05). In the elderly, however, the muscular activity of the RF was lower outdoors than indoors (p<.05). When compared to those in there forties, the muscular activity of the outdoor RF significantly decreased in the elderly group (P<.05). The muscular activity of the biceps femoris (BF) in the elderly decreased significantly outdoors compared to indoors (p<.05). CONCLUSION: For the elderly, increasing the exposure to the new environments or focusing on the performance of repeated movements for gradual speed control and precise movements is required to maintain normal gaits and movements that are less affected by environmental changes.

• Journal of the Korean Society of Physical Medicine
• /
• v.14 no.3
• /
• pp.29-37
• /
• 2019

PURPOSE: Prone hip extension (PHE) has been used for assessment of lumbo-pelvic movement and strengthening exercise for weakness of the hip joint muscles in patients with chronic low back pain (CLBP). On the other hand, few studies have examined which are the best PHE exercises to activate the gluteus maximus (GM) selectively in physical therapy practice. To aim of this study compared the muscle activity of the GM, rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA) during these four different prone hip extensions, PHE, PHE with quadriceps activation (PHEQA), PHE with ankle dorsiflexion (PHEAD), and PHE with ankle plantarflexion (PHEAP), in subjects with CLBP. METHODS: Nineteen subjects with low back pain participated in this study. Subject performed four PHE exercises and surface electromyography (EMG) was used to evaluate the muscle activity. Data were analyzed by one-way repeated-measures analysis of variance (${\alpha}=.05/3=.017$) and a Bonferroni adjustment was performed if a significant difference was found. RESULTS: The muscle activities recorded by EMG showed significant among the four exercises. The muscle activity of the GM increased significantly during PHEQA than during PHEAP (P=.012). CONCLUSION: PHEQA is the most effective exercise for eliciting greater GM muscle activation among the four PHE exercises in subjects with CLBP.

• Physical Therapy Rehabilitation Science
• /
• v.8 no.2
• /
• pp.61-66
• /
• 2019

Objective: The purpose of this study was to investigate the effects of resistance applied in various directions on lower extremity muscle activity and balance during squat exercise performance. Design: Cross-sectional study. Methods: Forty-one adults (19 males and 22 females) agreed to the study purpose and procedures. All subjects randomly performed squat exercises with an intensity of overcoming 10% of body weight resistance pulled forward, backward and general squats with $60^{\circ}$ of knee joint flexion. Electromyography was used to measure muscle activity of the vastus medialis oblique (VMO), rectus femoris (RF), vastus lateralis oblique (VLO), biceps femoris (BF), and semitendinosus (ST) muscles. The Wii Balance Board was used to assess balance during the three-method squat operation. Each operation was measured three times for 10 seconds. Results: There were significant differences in muscle activities of the VMO, RF, VLO, ST and balance ability with the application of three directions of resistance (p<0.05). Post hoc comparisons revealed that squats performed with resistance pulled in the backward direction resulted in higher VMO, RF and VLO activity than with the resistance placed in a pulled forward direction (p<0.05). In the ST, resistance applied in the pulled forward direction showed greater muscle activity compared to the pulled backward direction (p<0.05). With balance, squats performed with resistance pulled in the forward direction showed greater muscle activity than with resistance applied in the pulled backward direction and during general squat performance (p<0.05). Conclusions: In this study, squat exercises performed with resistance applied in the direction of pulling backwards was found to be the most effective in improving quadriceps muscle strength and balance. It is effective to provide resistance that is placed in the forward when it is difficult to perform a general squat due to weakness of the quadriceps.

• PNF and Movement
• /
• v.17 no.2
• /
• pp.311-319
• /
• 2019

Purpose: This study was conducted to determine the structural change in knees caused by quadriceps angle and the muscle activity in lower limbs. Indirect intervention was provided by using taping for stability in the ankle joints, which affected patellofemoral pain. Methods: The subjects in this study were 20 patients with patellofemoral pain who visited ${\bigcirc}{\bigcirc}{\bigcirc} $ Hospital in Busan. The visual analogue scale measured the dynamic quadriceps angle and the degree of pain felt by the patients while walking down stairs, which was a known factor of patellofemoral pain. In addition, muscle activities in the rectus femoris, vastus lateralis, vastus medialis, tibialis anterior, peroneus longus, and biceps femoris, which affect the knees and ankles, were measured using surface electromyography. The muscle activities were converted into %RVC for this study. The data obtained in this study were analyzed with the Wilcoxon signed-rank test using the SPSS Ver. 25.0 statistical program. The significance level ${\alpha}$ was 0.05. Results: The study results showed that the pain and dynamic quadriceps angle were significantly reduced statistically when applying the calcaneus fixation taping (p<0.05). Muscle activity in the lower limbs was significantly decreased in the vastus medialis, vastus lateralis, and tibialis anterior (p<0.05). Conclusion: The summary of the study results verified that the calcaneus fixation taping reduced the pain and dynamic quadriceps angle by providing stability in the ankle joints. It also produced efficient movement due to the difference in lower-limb muscle activity.

• The Journal of Korean Physical Therapy
• /
• v.34 no.1
• /
• pp.38-44
• /
• 2022

Purpose: The purpose of this study was to investigate the effects of complex training on injury, flexibility, and muscle stiffness in high school male football players. Methods: A total of 60 football players were included in the study and were divided into three groups viz. the complex training group (CTG), 11+ training group (11+TG), and traditional training group (TTG). Injuries were recorded based on the prospective investigation method after starting the study, and the flexibility and muscle stiffness of the subjects were evaluated. Results: The research results showed that the injury rate per match was significantly lower in the CTG and 11+TG than the TTG. In the CTG, the flexibility of the hamstrings significantly increased and the stiffness of the rectus femoris (RF), biceps femoris (BF), and tensor fascia latae (TFL) muscles significantly decreased (p<0.05). In the 11+TG, the stiffness of the RF significantly decreased (p<0.05). In the TTG, the flexibility of the hamstrings significantly increased (p<0.05). Hamstring flexibility showed a significantly higher increase in the CTG and TTG compared to the 11+TG (p<0.05). Also, the stiffness of the RF and TFL muscles showed a significantly higher decrease in the CTG compared to the 11+TG and TTG (p<0.05). The stiffness of the BF muscles too showed a more significant decrease in the CTG compared to the TTG (p<0.05). Conclusion: The complex training method of the Fédération International de Football Association (FIFA) 11+ and self-myofascial release (SMFR) as a warm-up program, prevent injuries, enhance flexibility, and lower muscle stiffness of football players in high school. Thus, it is necessary to ensure the widespread use of the complex training program by instructors and players under the supervision of the Korea Football Association (KFA), given its reliability in preventing injuries and improving the performance of football players.