Acute Intraocular Pressure Responses to Resistance Training in Combination With Blood Flow Restriction.

Objective: To determine the effect of blood flow restriction (BFR) applied to the legs at different pressures (40% and 60%) on intraocular pressure (IOP) during the execution of ten repetitions maximum (10RM) in the half-squat exercise. Methods: Quasi-experimental, prospective study with 17 healthy physically active subjects (9 males and 8 females; 24.1 ± 4.2 years). Two sessions were conducted. The 10RM load was determined in the first session. The second session consisted of 10RM under three BFR conditions (no-BFR, 40%-BFR, and 60%-BFR) that were applied in random order. IOP was measured before each condition, immediately after each repetition, and after 1 minute of passive recovery. A two-way repeated-measures ANOVA (restriction type [no-BFR, 40%-BFR, and 60%-BFR] x measurement point [basal, repetitions 1-10, and recovery]) was applied on the IOP measurements. Results: A significant main effect of the BFR condition (p = .022, ƞp2 = 0.21) was observed due to the significantly higher mean IOP values for the 60%-BFR (19.0 ± 0.7 mmHg) compared to the no-BFR (18.0 ± 0.8 mmHg; p = .048, dunb = 1.30). Non-significant differences with a large effect size were reached between 60%-BFR and 40%-BFR (18.1 ± 0.8 mmHg; p = .081, dunb = 1.16) and between no-BFR and 40%-BFR (p = .686, dunb = 0.18). IOP increased approximately 3-4 mmHg from baseline to the last repetition. Conclusions: Low-pressure BFR (40%-BFR) in combination with moderate-load (10RM load) resistance exercise could be an effective and safe strength training strategy while avoiding IOP peaks associated with heavy-load resistance exercises. These findings incorporate novel insights into the most effective exercise strategies in individuals who need to maintain stable IOP levels (e.g., glaucoma patients).

Effects of horse-riding squat exercise plus Governor Vessel-regulating Tuina therapy on static balance function in patients with stroke / 针灸推拿医学（英文版）

Objective:To observe the effect of horse-riding squat exercise plus Governor Vessel-regulating Tuina(Chinese therapeutic massage)therapy on static balance function in patients with stroke.Methods:A total of 176 stroke patients were enrolled as the study subjects and divided into four groups by the random number table method,namely horse-riding squat+Tuina group,horse-riding squat group,Tuina group,and control group,with 44 cases in each group.The control group was treated with rehabilitation balance training.The horse-riding squat+Tuina group,horse-riding squat group,and Tuina group were treated with additional horse-riding squat exercise plus Tuina,horse-riding squat exercise,and Tuina treatment,respectively.Four weeks of treatment was regarded as one treatment course.After 1 treatment course,the balance function of the four groups was compared.Results:After treatment,the ellipse area of motion and the length of motion in all four groups were reduced,and the intra-group differences were all statistically significant(P＜0.05).The difference in the ellipse area of motion before and after treatment in the horse-riding squat+Tuina group and the horse-riding squat group was larger than that in the control group,and the differences were statistically significant(P＜0.05).The difference in the ellipse area of motion before and after treatment in the horse-riding squat+Tuina group was larger than that in the Tuina group,and the difference was statistically significant(P＜0.05).The difference in the length of motion before and after treatment in the horse-riding squat+Tuina group,the horse-riding squat group,and the Tuina group was greater than that in the control group,and the differences were statistically significant(P＜0.05).There was no statistically significant difference in the pairwise comparison between the horse-riding squat+Tuina group,the horse-riding squat group,and the Tuina group(P＞0.05).Conclusion:Horse-riding squat exercise plus Governor Vessel-regulating Tuina therapy can effectively improve the static balance function in patients with stroke.Training the affected lower limb weight-bearing exercise,adjusting the center of gravity distribution,and promoting the mutual balance and coordination between muscle groups may be the mechanism of improving the static balance function.

Protocol-optimizing study of combining Tuina and horse-riding squat exercise for knee osteoarthritis / 针灸推拿医学（英文版）

Objective: To evaluate the efficacy of Tuina (Chinese therapeutic massage) manipulation plus horse-riding squat exercise in treating knee osteoarthritis (KOA) and optimize the combining protocol. Methods: Based on a 2×2 factorial design, 120 eligible KOA patients were randomized into a manipulation group (group A1B2), a manipulation plus horse-riding squat group (group A1B1), a sitting knee-adjustment group (group A2B2 group), and a sitting knee-adjustment plus horse-riding squat group (group A2B1), with 30 cases in each group. The intervention was conducted three times a week, lasting for four weeks. The Western Ontario and McMaster Universities osteoarthritis index (WOMAC) was taken as the major measure for efficacy evaluation (including three component scores, pain, stiffness, and daily function, and total score). Results: The three component scores (pain, stiffness, and daily function) and the total score of WOMAC showed significant differences after the intervention in the four groups (P<0.05). There were significant inter-group differences in the WOMAC stiffness score amongst the four groups after the intervention (P<0.05). In group A1B1, the step length, stride, walking speed, and knee joint flexion angle changed significantly after treatment (P<0.05). After the intervention, the step length changed significantly in group A1B2 (P<0.05), and the walking speed changed significantly in group A2B1 (P<0.05). There were no significant differences in the step length, stride, walking speed, or knee joint flexion angle among the four groups (P>0.05). The extensor peak torque at 180 °/s changed significantly in group A1B2 after treatment (P<0.05). Neither the intra-group nor the inter-group comparisons of the four groups revealed significant differences in the other isokinetic muscle strength parameters (P>0.05). The main effect of manipulation showed significant in affecting the WOMAC pain and total scores (P<0.05). The main effect of horse-riding squat exercise showed significant in affecting the WOMAC pain and stiffness scores (P<0.05). Conclusion: The four treatment protocols all can improve the symptoms of KOA, for instance, relieving pain and stiffness, and enhancing daily function. Group A2B1 produces the most eminent effect in relieving joint stiffness. The main effects of both manipulation and horse-riding squat exercise are significant in reducing pain. Besides, the main effect of horse-riding squat exercise is significant in relieving joint stiffness.

Muscle activities of lower extremity and erector spinae muscles according to ankle joint position during squat exercise.

OBJECTIVE: The purpose of this study was to investigate the most effective ankle joint position for squat exercise by comparing muscle activities of lower extremity and erector spinae muscles in different ankle joint positions. METHODS: Thirty-seven normal healthy adults in their 20s participated in this study. Muscle activities of dominant vastus medialis oblique, vastus lateralis, biceps femoris, and erect spinae were measured in three ankle joint positions; dorsiflexion, neutral, and plantar flexion. RESULTS: Muscle activities of the vastus medialis oblique, vastus lateralis, and erector spinae muscles were statistically different in the three ankle joint positions during squat exercise (p< 0.05). Vastus medialis oblique muscles showed higher muscle activity in ankle plantar flexion than in the dorsiflexion or neutral positions (plantar flexion > neutral position, +3.3% of maximal voluntary isometric contraction (MVIC); plantar flexion > dorsiflexion, +12.2% of MVIC, respectively). Vastus lateralis muscles showed 7.1% of MVIC greater muscle activity in the neutral position than in dorsiflexion, and erector spinae muscles showed higher muscle activity in dorsiflexion than in plantar flexion or in the neutral position (dorsiflexion > neutral position, +4.3% of MVIC; dorsiflexion > plantar flexion, +7.1% of MVIC, respectively). CONCLUSION: In squat exercises designed to strengthen the vastus medialis oblique, ankle joint plantar flexion is probably the most effective ankle training position, and the dorsiflexion position might be the most effective exercise for strengthening the erector spinae muscle.

Effects of Kinesio Taping with Squat Exercise on the Muscle Activity, Muscle Strength, Muscle Tension, and Dynamic Stability of Softball Players in the Lower Extremities: A Randomized Controlled Study.

BACKGROUND AND PURPOSE: Knee injuries are common among female softball players, and the stability of the lower extremities and the strength of the knee are essential factors for them. The purpose of this study was to investigate the effect of Kinesio taping with squat exercise (KTSE) on lower extremity muscle activity, muscle strength, muscle tone, and dynamic stability of softball players. METHODS: In this study, 40 softball players were randomly assigned to the KTSE group and sham taping with squat exercise (SKTSE) group. All subjects were tested three times a week for 6 weeks, i.e., for a total of 18 times. To evaluate the lower-extremity muscle activity, muscle strength, and muscle tone of the lower extremities, as well as dynamic stability, we used Noraxon Mini DTS, a digital muscular meter from JTech Medical, MyotonPRO, and the side hop test (a clinical evaluation method), respectively. These items were measured before the experiment and 6 weeks after the start of the experiment. RESULTS: Both groups showed significant differences in lower-extremity muscle activity, muscle strength, muscle tone, and dynamic stability (p < 0.05). After the experiment, significant effects on lower-extremity muscle activity, muscle strength, muscle tone, and dynamic stability were observed in the KTSE group compared with in the SKTSE group (p < 0.05). CONCLUSIONS: KTSE did not have a negative effect on all items of the functional performance test. KTSE improved lower-extremity muscle activity, muscle strength, muscle tone, and dynamic stability.

Lactacidemia in two different weight training models / Lactacidemia em dois modelos diferentes de treino de musculação

The knowledge of the physiological aspects in the execution of the training in the bodybuilding is important to improve the training; being the lactate concentration an important marker applied in several types of exercises. Some studies have evaluated lactacidemia and training models but did not use squatting in their protocols. The aim of the study was to analyze blood lactate concentration in free squat exercise training in two training models: strength and resistance.Experimental study with a sample of five men of 24 ± 4.6 years, physically active and practicing for at least one year, with no history of orthopedic and cardiovascular problems. The tests were performed in two days, in the strength session the volunteers performed 12 sets, 6 to 12 maximal repetitions and in the resistance session 12 series, 13 to 20 maximum repetitions. In both tests the interval was 1 minute and 30 seconds between sets and 2 minutes every 4 sets. Blood lactate was collected at rest, during and after the test.No significant differences were found in the lactate concentration during and after the tests in the strength training and the resistance training. However, the lactacidemia variation between the first and last collection presented a significantly higher result in strength training. We conclude that the models of strength and resistance training, in the free squat exercise, do not present significant differences in lactate concentration during and after the tests. The total lactacidemia variation was greater in strength training.

O conhecimento dos aspectos fisiológicos na execução do treino na musculação é importante para aprimorarmos os treinamentos; sendo a concentração de lactato um importante marcador aplicado em diversos tipos de exercícios. Alguns estudos já avaliaram lactacidemia e modelos de treinamento, porém não utilizaram o agachamento em seus protocolos. O objetivo do estudo foi analisar a concentração de lactato sanguíneo no treino do exercício agachamento livre em dois modelos de treinamento: força e resistência. Estudo experimental, com amostra de cinco homens de 24 ± 4.6 anos, fisicamente ativos e praticantes há pelo menos um ano, sem histórico de problemas ortopédicos e cardiovasculares. Os testes foram realizados em dois dias, na sessão de força os voluntários executaram 12 séries, 6 a 12 repetições máximas e na sessão de resistência 12 séries, 13 a 20 repetições máximas. Em ambos os testes o intervalo foi de 1 minuto e 30 segundos entre as séries e de 2 minutos a cada 4 séries. O lactato sanguíneo foi coletado no repouso, durante e no pós-teste. Não foram encontradas diferenças significativas na concentração de lactato durante e após os testes no treino de força e no treino de resistência. No entanto, a variação da lactacidemia entre a primeira e a última coleta apresentou resultado significativamente maior no treino de força. Concluímos que os modelos de treinamento de força e de resistência, no exercício agachamento livre, não apresentam diferenças significativas na concentração de lactato durante e após os testes. Sendo a variação total de lactacidemia maior no treinamento de força.

The Influence of the Menstrual Cycle on Muscle Strength and Power Performance.

This study aimed to investigate the fluctuations of muscle performance in the Smith machine half-squat exercise during three different phases of the menstrual cycle. Thirteen resistance-trained and eumenorrheic women volunteered to participate in the study (58.6 ± 7.8 kg, 31.1 ± 5.5 years). In a pre-experimental test, the half-squat one-repetition maximum (1RM) was measured. Body mass, tympanic temperature and urine concentration of the luteinizing hormone were estimated daily for ~30 days to determine the early follicular phase (EFP), the late follicular phase (LFP), and the mid-luteal phase (MLP) of the menstrual cycle. On the second day of each phase, performance of the Smith machine half-squats was assessed using 20, 40, 60 and 80% of one repetition maximum (1RM). In each load, force, velocity, and power output were measured during the concentric phase of the exercise by means of a rotatory encoder. The data were analyzed using one-way repeated measures ANOVA coupled with magnitude-based inferences. Overall, force, velocity and power output were very similar in all menstrual cycle phases with unclear differences in most of the pairwise comparisons and effect sizes >0.2. The results of this investigation suggest that eumenorrheic females have similar muscle strength and power performance in the Smith machine half-squat exercise during the EFP, LFP, and MLP phases of the menstrual cycle.

Effect of Visual Feedback Squat Motion on Core Muscles Thickness of Young People with Lower Back Pain

PURPOSE: This study examined the effect of visual feedback squat on the core muscle thickness of young adults experiencing back pain. METHODS: Thirty adult men and women who experienced back pain were assigned randomly to 15 members of the visual feedback squat group (VSG) and 15 of the normal squat group (NSG) to train three times a week for a total of eight weeks. The core muscle thickness was compared prior to the test for four weeks and eight weeks after the test by dividing it into warm-up exercise, main exercise, and 10 minutes finishing exercise. Before, and four weeks and eight weeks later, the thickness of the core muscle was compared using an ultrasonic imaging system. Repeated measured ANOVA was performed to compare the groups, and a Bonferroni test was performed as a post-hoc test to assess the significance of the timing of the measurements in each group according to the periods. An independent t-test was conducted to test the significance between the groups according to the measurement points. RESULTS: A significant change in the main effects of time and interactions of the time difference in muscle thickness of transvers abdominis were observed between the visual feedback squat and control groups according to the measurement point (p0.05). CONCLUSION: These findings suggest that visual feedback squat exercise is expected to have positive effects on the development of transverse abdominis in core muscles.

Effect of Squat Exercises on Lung Function in Elderly Women with Sarcopenia.

We explored whether a mechanically-assisted squat exercise improved muscle mass, muscle function, and pulmonary function in elderly women with or without sarcopenia. In total, 76 community-dwelling elderly subjects (>60 years of age) were screened. We ultimately included 30 subjects who completed more than 80% of the six-week course of mechanically-assisted squat exercises (three days per week, 30 min per day). We measured body composition, lung function, knee extensor strength, hand grip strength, and the 3-min walk distance (3MWD) before and after the exercise program. Subjects with sarcopenia had poor hand grip strength and knee extensor strength, and a slow walking speed. Their lung function parameters, including forced vital capacity (FVC), was lower than those of the controls. After six weeks of squat exercises, the hand grip strength, knee extensor strength, and 3MWD increased significantly in both groups. Appendicular skeletal muscle mass and leg lean mass were increased in subjects without sarcopenia. The FVC (L) increased significantly only in the sarcopenia group (p = 0.019). The mechanically-assisted squat exercise program increased muscle function and lung function, including FVC, in patients with sarcopenia. Muscle mass increased in subjects without sarcopenia.

How to squat? Effects of various stance widths, foot placement angles and level of experience on knee, hip and trunk motion and loading.

BACKGROUND: Squatting is a core exercise for many purposes. The tissue loading during squatting is crucial for positive adaptation and to avoid injury. This study aimed to evaluate the effect of narrow, hip and wide stance widths, foot position angles (0°, 21°, and 42°), strength exercise experience, and barbell load (0 and 50% body weight, experts only) during squatting. METHODS: Novice (N = 21) and experienced (N = 21) squatters performed 9 different variations of squats (3 stance widths, 3 foot placement angles). A 3D motion capture system (100 Hz) and two force plates (2000 Hz) were used to record mediolateral knee displacement (ΔD*), range of motion (RoM) at the hip and knee joints, and joint moments at the hip, knee, and lower back. RESULTS: Both stance width and foot placement angles affected the moments at the hip and knee joints in the frontal and sagittal planes. ΔD* varied with stance width, foot placement angles and between the subjects' level of experience with the squat exercise as follows: increasing foot angle led to an increased foot angle led to an increased ΔD*, while an increased stance width resulted in a decreased ΔD*; novice squatters showed a higher ΔD*, while additional weight triggered a decreased ΔD*. CONCLUSIONS: Suitable stance width and foot placement angles should be chosen according to the targeted joint moments. In order to avoid injury, special care should be taken in extreme positions (narrow stand-42° and wide stance-0°) where large knee and hips joint moments were observed.

A study on muscle activity and ratio of the knee extensor depending on the types of squat exercise.

[Purpose] For preventing the patellofemoral pain syndrome, this study aims to suggest a proper squat method, which presents selective muscle activity of Vastus Medialis Oblique and muscle activity ratios of Vastus Medialis Oblique/Vastus Lateralis by applying squat that is a representative weight bearing exercise method in various ways depending on the surface conditions and knee bending angles. [Subjects and Methods] An isometric squat that was accompanied by hip adduction, depending on the surface condition and the knee joint flexion angle, was performed by 24 healthy students. The muscle activity and the ratio of muscle activity were measured. [Results] In a comparison of muscle activity depending on the knee joint flexion angle on a weight-bearing surface, the vastus medialis oblique showed a significant difference at 15° and 60°. Meanwhile, in a comparison of the muscle activity ratio between the vastus medialis oblique and the vastus lateralis depending on the knee joint flexion angle on a weight-bearing surface, significant differences were observed at 15° and 60°. [Conclusion] An efficient squat exercise posture for preventing the patellofemoral pain syndrome is to increase the knee joint bending angle on a stable surface. But it would be efficient for patients with difficulties in bending the knee joint to keep a knee joint bending angle of 15 degrees or less on an unstable surface. It is considered that in future, diverse studies on selective Vastus Medialis Oblique strengthening exercise methods would be needed after applying them to patients with the patellofemoral pain syndrome.

Comparison of hamstring-to-quadriceps ratio between accelerating and decelerating sections during squat exercise.

[Purpose] The aim of this study was to compare hamstring-to-quadriceps ratio between the accelerating and decelerating sections for anterior cruciate ligament protection during squat exercise. [Subjects and Methods] Nine asymptomatic males were enrolled in this study. The hamstring (medial part) and quadriceps (rectus femoris) muscle activities during squat exercise were measured, and the squat exercises were classified into two sections (accelerating and decelerating) by using an accelerometer. [Results] The hamstring-to-quadriceps ratio was significantly higher in the decelerating section than in the accelerating section during the squat exercise. [Conclusion] Application of an increasing decelerating section strategy during the squat exercise can prevent damage in patients with a weakened anterior cruciate ligament due to sports activities.

Effect of 3 Different Applications of Kinesio Taping Denko® on Electromyographic Activity: Inhibition or Facilitation of the Quadriceps of Males During Squat Exercise.

Kinesio taping consists of a technique which uses the application of an elastic adhesive tape. It has become a widely used rehabilitation modality for the prevention and treatment of musculoskeletal disorders. The objective of this study was to verify the effect of the application of Kinesio Taping Denko® in three conditions (facilitation, inhibition, and placebo) on the electromyographic activity of the quadriceps and hamstrings muscles on facilitating or inhibiting the muscle function and on the perceived exertion during the barbell back squat exercise in healthy male subjects. METHODS: It was a randomized, single-blinded and controlled study in which 18 males (28.0 ± 6.7 years old; 85.8 ± 8.2 kg mass; 1.80 ± 0.07 m tall; 0.97 ± 0.04 m lower limb length) performed barbell back squat exercise with different conditions of Kinesio Taping Denko® applications: Facilitation, inhibition and placebo. Previous to the mentioned conditions, all individuals were assessed without applying kinesio Taping Denko® during the exercise. OMNI scale was used after each set for perceived exertion evaluation. No differences (p < 0.05) in the electromyographic activity of the biceps femoris, vastus lateralis and vastus medialis or OMNI scale were recorded under any conditions. The results show that the kinesio taping denko® may not alter the magnitude of the electromyography activity of vastus lateralis, vastus medialis, and biceps femoris during the squat exercise. Furthermore, the perceived exertion was not affected by the kinesio taping denko® application.

Activation of back and lower limb muscles during squat exercises with different trunk flexion.

[Purpose] The purpose of this study was to investigate the activation of back and lower limb muscles in subjects who were performing a squat exercise at different angles of trunk flexion. [Subjects and Methods] Twenty healthy subjects (age 21.1± 1.8 years, height 168.7 ± 8.2 cm, weight 66.1 ± 12.3 kg) volunteered. The activation of the erector spinae muscle, rectus femoris muscle, gluteus maximus muscle and biceps femoris muscle was observed while the subjects performed squat exercises with a trunk flexion of 0°, 15°, and 30°. [Results] The erector spinae muscle, gluteus maximus muscle, and biceps femoris muscle were activated more during the squat exercise with the trunk flexion at 30° than the exercise with the trunk flexion at 0°. The rectus femoris muscle showed a tendency to decrease as the truck flexion increased. [Conclusion] Squat exercise be executed while maintaining an erect trunk posture if one wishes to strengthen the quadriceps muscle while reducing the load on the lower back.

Effects of Traditional Versus Horizontal Inertial Flywheel Power Training on Common Sport-Related Tasks.

This study aimed to analyze the effects of power training using traditional vertical resistance exercises versus direction specific horizontal inertial flywheel training on performance in common sport-related tasks. Twenty-three healthy and physically active males (age: 22.29 ± 2.45 years) volunteered to participate in this study. Participants were allocated into either the traditional training (TT) group where the half squat exercise on a smith machine was applied or the horizontal flywheel training (HFT) group performing the front step exercise with an inertial flywheel. Training volume and intensity were matched between groups by repetitions (5-8 sets with 8 repetitions) and relative intensity (the load that maximized power (Pmax)) over the period of six weeks. Speed (10 m and 20 m), countermovement jump height (CMJH), 20 m change of direction ability (COD) and strength during a maximal voluntary isometric contraction (MVIC) were assessed before and after the training program. The differences between groups and by time were assessed using a two-way analysis of variance with repeated measures, followed by paired t-tests. A significant group by time interaction (p=0.004) was found in the TT group demonstrating a significantly higher CMJH. Within-group analysis revealed statistically significant improvements in a 10 m sprint (TT: -0.17 0.27 s vs. HFT: -0.11 0.10 s), CMJH (TT: 4.92 2.58 cm vs. HFT: 1.55 2.44 cm) and MVIC (TT: 62.87 79.71 N vs. HFT: 106.56 121.63 N) in both groups (p < 0.05). However, significant differences only occurred in the 20 m sprint time in the TT group (-0.04 0.12 s; p = 0.04). In conclusion, the results suggest that TT at the maximal peak power load is more effective than HFT for counter movement jump height while both TT and HFT elicited significant improvements in 10 m sprint performance while only TT significantly improved 20 m sprint performance.

Effects of the slow speed-targeting squat exercise on the vastus medialis oblique/vastus lateralis muscle ratio.

[Purpose] This study investigated the effects of the slow speed-targeting squat exercise on the vastus medialis oblique/vastus lateralis ratio. [Subjects] Ten asymptomatic men were recruited. [Methods] The EMG activities of the vastus medialis oblique and vastus lateralis muscles were recorded using surface electrodes. The subject performed the squat exercise under 3 different conditions. [Results] The vastus medialis oblique/vastus lateralis ratio in condition 2 (1.5 ± 0.7) was significantly higher than that in conditions 1 and 3 (1.0 ± 0.5, 1.1 ± 0.8, respectively) [Conclusion] Therefore, an effectively slow movement speed is recommended for selective strengthening of vastus medialis oblique using a slow speed-targeting device that provides biofeedback.

Impact of decline-board squat exercises and knee joint angles on the muscle activity of the lower limbs.

[Purpose] This study aims to investigate how squat exercises on a decline board and how the knee joint angles affect the muscle activity of the lower limbs. [Subjects] The subjects were 26 normal adults. [Methods] A Tumble Forms wedge device was used as the decline board, and the knee joint angles were measured with a goniometer. To examine the muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior of the lower limbs, a comparison analysis with electromyography was conducted. [Results] The muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior increased with increased knee joint angles, both for squat exercises on the decline board and on a flat floor. When the knee joint angle was 45°, 60°, and 90°, the muscle activity of the rectus femoris was significantly higher and that of the tibialis anterior was significantly lower during squat exercises on the decline board than on the flat floor. When the knee joint angle was 90°, the muscle activity of the gastrocnemius lateralis was significantly lower. [Conclusion] Squat exercises on a decline board are an effective intervention to increase the muscle activity of the rectus femoris with increased knee joint angles.

Effects of fast and slow squat exercises on the muscle activity of the paretic lower extremity in patients with chronic stroke.

[Purpose] The purpose of this study was to investigate the effects of the speed of squat exercises on paretic lower extremity muscle activity in patients with hemiplegia following a stroke. [Subjects and Methods] Ten stroke patients performed fast and slow squat exercises for 2 seconds and 8 seconds, respectively. The muscle activities of the paretic and non-paretic sides of the rectus femoris muscle, the biceps femoris muscle, and the tibialis anterior muscle were assessed and compared using surface electromyography. [Results] The paretic side of the rectus femoris muscle showed statistically significant differences in the fast squat exercise group, which demonstrated the highest muscle activity during the rapid return to the upright position. [Conclusion] The rectus femoris muscle showed the highest muscle activity during the return to the upright position during the fast squat exercise, which indicates that the rectus femoris muscle is highly active during the fast squat exercise.

Effects of lifting the non-paretic foot on muscle activity during the semi-squat exercise in hemiplegic patients.

[Purpose] This study compared the electromyographic activity of the quadriceps in hemiplegic patients during the downward, maintenance, and upward phases of squat exercises performed with the feet parallel and with the non-paretic foot lifted. [Subjects] A total of 17 hemiplegic patients (9 males and 8 females) volunteered for this study. [Methods] All subjects performed squat exercises with the knees flexed to 30° and with the feet parallel (shoulder-width apart) or with lifting of the non-paretic foot (normalized to 25% of the knee height). [Results] The activity of the rectus femoris, vastus medialis oblique, and vastus lateralis muscles was significantly higher during squat exercises performed with the non-paretic foot lifted than with the feet parallel to each other. The activity of all muscles during the maintenance phase of the exercises was greater than that during the downward and upward phases. [Conclusion] Lifting the non-paretic foot during squats may represent an effective exercise for motor function rehabilitation in hemiplegic patients.

The effects of squatting with visual feedback on the muscle activation of the vastus medialis oblique and the vastus lateralis in young adults with an increased quadriceps angle.

[Purpose] The purpose of this study was to identify the effects of performing squat exercises with visual feedback on the activation of the vastus medialis oblique (VMO) and vastus lateralis (VL) muscles in young adults with an increased quadriceps angle (Q-angle). [Subjects] This study used a motion analysis program (Dartfish, Switzerland) to select 20 young adults with an increased Q-angle, who were then divided into a squat group that received visual feedback (VSG, n=10) and a squat group that received no visual feedback (SG, n=10). [Methods] The intensity of exercises was increased every two weeks over a six-week exercise period in both groups. A visual marker was attached to the patella of the subjects in the VSG, and they then performed squat exercises with a maximum of 90° of knee flexion within a route marked on a mirror. The SG performed squat exercises with a maximum 90° of knee flexion without attaching a visual feedback device. [Results] Analysis of the muscle activation due to 90° squat exercises indicated that both groups had statistically significant increases in activation of the VL. The VSG exhibited statistically significant increases in activation of the VMO. [Conclusion] This study confirmed that squat exercises with visual feedback are effective in activation of the VMO and VL muscles. The findings are meaningful in terms of preventing the occurrence of patellofemoral pain.