Application of Convolutional Neural Network in Identifying Different Levels of Isokinetic Exercise Efforts / 法医学杂志

Objective To develop a convolutional neural network （CNN） that can identify isokinetic knee exercises moment of force-time diagrams under different levels of efforts. Methods The 200 healthy young volunteers performed concentric isokinetic right knee flexion-extension reciprocating exercises with maximal effort as well as half the effort at angular velocities of 30°/s and 60°/s twice, respectively, with an interval of 45 min. The moment of force-time diagrams were collected. The 200 subjects were randomly divided into the training set （140 subjects） and the testing set （60 subjects）. The moment of force-time diagrams from subjects in the training set were used to train CNN model, and then the fully trained model was used to predict types of curves from the testing set. Random sampling of subjects along with subsequent development of models were performed 3 times. Results Under the circumstances of isokinetic knee exercises with maximal effort and half the effort, 2 400 moment of force-time diagrams were produced, respectively. Classification accuracy rates of the CNN models after the 3 trainings were 91.11%, 90.49% and 92.08%, respectively, and the average accuracy rate was 91.23%. Conclusion The CNN models developed in this study have a good effect on differentiating isokinetic moment of force-time diagrams of maximal effort exercises from those made with half the effort, which can contribute to identifying levels of efforts exerted by subjects during isokinetic knee exercises.

Effects of Kinesio Taping on Muscle Strength of Knees in Female Students / 中国康复理论与实践

Objective To investigate the effects of Kinesio taping on function of knees in girls. Methods 20 female students were tested the peak torque of centripedal and eccentric contraction of knee flexion and extension with Biodex isokinetic testing at 60°/s angular veloci-ty, with Kinesio taping, placebo taping and without taping. Their amplitude root of mean square (RMS) of surface electromyography of vas-tus medialis (VM), rectus femoris (RM) and vastus lateralis (VL) were also recorded. Results For centripedal isokinetic contraction, the rela-tive extensors peak torque was the most as Kinesio taping (P0.05). Standardized RMS of VM and VL were the least as Kinesio taping (P0.05). For eccentric isokinetic contraction, the relative extensor peak torque of both extensors and flexors were the most as Kinesio taping (P0.05). Conclusion Kinesio taping may enhance the strength of centripedal, eccentric contractions of quadriceps and eccentric contractions of hamstring, and increase the muscle fibers recruitment of VM and VL.

Effects of Kinesio Taping on Muscle Strength of Knees in Female Students / 中国康复理论与实践

@#Objective To investigate the effects of Kinesio taping on function of knees in girls. Methods 20 female students were tested the peak torque of centripedal and eccentric contraction of knee flexion and extension with Biodex isokinetic testing at 60°/s angular velocity, with Kinesio taping, placebo taping and without taping. Their amplitude root of mean square (RMS) of surface electromyography of vastus medialis (VM), rectus femoris (RM) and vastus lateralis (VL) were also recorded. Results For centripedal isokinetic contraction, the relative extensors peak torque was the most as Kinesio taping (P<0.01). There was no significant difference in relative flexor peak torque (P> 0.05). Standardized RMS of VM and VL were the least as Kinesio taping (P<0.01), but not significantly different of RF among all the conditions (P>0.05). For eccentric isokinetic contraction, the relative extensor peak torque of both extensors and flexors were the most as Kinesio taping (P<0.01), while the Standardized RMS of VM and VL were the least (P<0.01), but no significant difference was observed in RF (P> 0.05). Conclusion Kinesio taping may enhance the strength of centripedal, eccentric contractions of quadriceps and eccentric contractions of hamstring, and increase the muscle fibers recruitment of VM and VL.

Efeitos de diferentes intervalos de recuperação na performance muscular em crianças / Effects of different rest intervals on muscular performance in children

O propósito do presente estudo foi verificar os efeitos de diferentes intervalos de recuperação (IRs) entre séries de exercícios resistidos em crianças nas variáveis de pico de torque (PT) e trabalho total (TT). Participaram do estudo 18 meninos (11,1 ± 0,52 anos, 32,9 ± 3,32 kg e 142,6 ± 4,78 cm, classificados nos estágios de Tanner 1 e 2). Foi utilizado um protocolo de três séries de dez repetições de exercícios isocinéticos em dois IRs (de um e dois minutos) nas velocidades de 60º/s e 180º/s. Não foram encontradas diferenças significativas (P> 0,05) no PT, TT entre os IRs de um e dois minutos nas velocidades de 60º/s e 180º/s. Conclui-se que as crianças necessitam de curtos períodos de recuperação (um minuto) para a manutenção da performance muscular, indicando assim uma alta capacidade de resistência à fadiga em exercícios resistidos de alta intensidade e com diferentes velocidades de execução.

The purpose of this study was to compare the effect of two different rest intervals between sets of isokinetic knee extension exercise on peak torque (PT), and Total Work (TW) in children. 18 boys (11.1 ± 0.52 yrs, 32.9 ± 3.32 kg and 142.6 ± 4.78 cm, Tanner stage 1 and 2) performed 3 sets of 10 unilateral isokinetic knee extension repetitions at 60°/s and 180°/s. The rest intervals between sets were 1 and 2 minutes. There was no significant decline in PT and TW when 1 and 2 min rest intervals were used at 60°/s and 180°/s. The present study indicated that children need only 1min to recover muscle performance, indicating high resistance to muscle fatigue during high intensity resistance exercise and different movement velocities.

Isokinetic muscle assessment after treatment of pectoralis major muscle rupture using surgical or non-surgical procedures

INTRODUCTION: Rupture of the pectoralis major muscle appears to be increasing in athletes. However, the optimal treatment strategy has not yet been established. OBJECTIVES: To compare the isokinetic shoulder performance after surgical treatment to that after non-surgical treatment for pectoralis major muscle rupture. METHODS: We assessed 33 pectoralis major muscle ruptures (18 treated non-surgically and 15 treated surgically). Horizontal abduction and adduction as well as external and internal rotation at 60 and 120 degrees/s were tested in both upper limbs. Peak torque, total work, contralateral deficiency, and the peak torque agonist-to-antagonist ratio were measured. RESULTS: Contralateral muscular deficiency did not differ between the surgical and non-surgical treatment modalities. However, the surgical group presented twice the number of athletes with clinically acceptable contralateral deficiency (<20 percent) for internal rotators compared to the non-surgical group. The peak torque ratio between the external and internal rotator muscles revealed a similar deficit of the external rotation in both groups and on both sides (surgical, 61.60 percent and 57.80 percent and non-surgical, 62.06 percent and 54.06 percent, for the dominant and non-dominant sides, respectively). The peak torque ratio revealed that the horizontal adduction muscles on the injured side showed similar weakness in both groups (surgical, 86.27 percent; non-surgical, 98.61 percent). CONCLUSIONS: This study included the largest single series of athletes reported to date for this type of injury. A comparative analysis of muscular strength and balance showed no differences between the treatment modalities for pectoralis major muscle rupture. However, the number of significant clinical deficiencies was lower in the surgical group than in the non-surgical group, and both treatment modalities require greater attention to the rehabilitation process, especially for the recovery of muscle strength and balance.

Evaluation of Elbow Stretch Reflex Using a Portable Hand-driven Isokinetic System in Normal Adults

OBJECTIVE: To evaluate normal healthy persons without spasticity to observe normal findings of the elbow stretch reflex using a newly developed, portable, hand-driven spasticity-measuring system. METHOD: Thirty normal persons without any disease involving the central or peripheral nervous system were enrolled in this study. The portable hand-driven isokinetic system is able to measure the joint angle, angular velocity, electromyographic (EMG) signals, and torque during elbow passive extension-flexion. One set of 10 passive elbow extension and flexion movements was performed for data acquisition at each angular velocity, including 60, 90, 120, 150 and 180 degrees per second (degrees/sec). Electromyographic data were collected from the biceps brachii and the triceps brachii. Torque data were collected from sensors around the wrist. RESULTS: We were able to detect EMG activity and torque in all subjects by using the new portable hand-driven isokinetic system. EMG activity and torque increased with incremental increase of angular velocities. The joint angle of maximal EMG activity according to different angular velocities did not show any significant difference (116degrees-127degrees in elbow extension and 37degrees-66degrees in elbow flexion). The joint angles of maximal torque according to different angular velocities were not significantly different either. CONCLUSION: Using the portable hand-driven isokinetic system on the elbows of normal subjects, we were able to obtain expected results. By considering our normal findings of the elbow stretch reflex using this system, we propose that the various aspects of spasticity-related data can be measured successfully.

The Effects of Isokinetic Strengthening of Trunk Muscles on Balance in Hemiplegic Patients

OBJECTIVE: To identify the effects of isokinetic strengthening of trunk muscles on balance in hemiplegic patients after stroke. METHOD: All participants were ambulatory hemiplegic patients, injured at least 6 months prior to study. The patients (n=16) were randomly divided into two groups. The control group received neurodevelopmental treatments and gait training 3 times a week. In addition to the same treatments provided for the control group, the experimental group received trunk isokinetic strengthening exercises using isokinetic dynamometer 3 times a week. Trunk muscle peak torque and balance in the experimental group were compared with those in control group at baseline and 4 weeks after treatments. RESULTS: There were no significant differences in age, lesion of hemiplegia, time after stroke onset, trunk muscle strength and Berg balance score before treatments between two groups. In the experimental group, peak torques of trunk extensor increased significantly at 60degrees/sec and 90degrees/sec at 4 weeks (p<0.05), but there were no significant improvements in peak torques of trunk flexor at all degree and extensor peak torques at 120degrees/sec. Both the extensor and flexors showed no significant changes in the control groups. In the experimental group, a mean percent change in peak torque involving the trunk extensor was significantly increased at 60degrees/sec. In the experimental group, Berg balance scores, 10 m gait velocity, sit to stand and gait 3 m and return, and 10 seconds stair up and down were improved (p<0.05). No significant improvements were noted in the control group. CONCLUSION: Isokinetic strengthening of trunk muscles can improve balance in hemiplegic patients.

THE CHANGE OF AUTONOMIC NERVOUS ACTIVITY AFTER ISOKINETIC EXERCISE / 体力科学

The purpose of this study was to investigate the fluctuation of the recovery period of autonomic nervous activity (ANA) after isokinetic exercise. Sixteen male subjects participated in this study after they turned in their consent forms.The subjects performed isokinetic knee extension-flexion exercise using BIODEX. We obtained the electro-cardiogram during the entire experiment. We calculated their heart rate (HR) and power spectral of R-R interval (LF is low frequency component, and HF is high frequency component. Both indexes were converted to a logarithm transformation as to lnHF and lnLF.) from pre-exercise period (PRE) and post-exercise period (POST).Some researchers reported that ΔlnHF of POST was lower and ΔLF/HF of POST was higher than those of PRE immediately after aerobic exercise; however, this study's results were in complete contrast.In conclusion, we found that the recovery periods after aerobic and isokinetic exercises of ANA are entirely different.

Isokinetic Evaluation of Shoulder Joint Strength in College Handball Players and General College Students

OBJECTIVE: To obtain the comparison data of the shoulder strength between handball players of college and general college students. METHOD: Fifteen subjects from each group, college handball players and general college students groups were tested. Peak torque, peak torque ratio of internal rotator to external rotator, peak torque to body weight ratio and average work during isokinetic exercise were studied. RESULTS: All of the parameters tested in handball players of college were greater than those of general college students. The peak torque in handball players was greater than that of general college students at 60o/sec, 180o/sec, which was statistically significant (p<0.05). The peak torque ratio of internal rotator to external rotator in dominant side of handball players was greater than the college group (p<0.05). The peak torque to body weight ratio at 60o/sec did not show significant differences between handball players of college and general college students. The average power at 60o/sec did not show significant differences between the two groups. CONCLUSION: The values of peak torque ratio of internal rotator to external rotator of the shoulder joint in dominant side of handball players were greater than those of the general college students. So it was suggested this result have to be considered in selecting handball players and exercise prescription.

The Validation of Musculoskeletal Model During Isokinetic Exercise at Knee Joint: An Experimental and Simulation Study / 대한정형외과연구학회지

PURPOSE: This study validated the musculoskeletal model of the human lower extremity by comparative study between calculated muscle parameters through simulation using modified hill-type model and measured muscle parameters through isokinetic exercise. The relationship between muscle forces and moments participated in motion was quantified from the results of simulation. MATERIALS AND METHODS: For simulation of isokinetic motion, a three-dimensional anatomical knee model was constructed using gait analysis. The EMG-force model was used to determine muscle activation level exciting muscles. The modified Hill-type model was used to calculate individual muscle force and moment in dynamic analysis. This method was validated by comparing analytical data with experimental data. RESULTS: The results showed that there was a significant correlation between calculated torques from simulation and measured torque from isokinetic motion experiments (R=0.97). We also found that muscle forces and moments during knee flexion and extension have nonlinearly proportional or inversely proportional relationship, since lower extremity muscles were simultaneously involved in flexion/extension motion and inner/outer rotation. CONCLUSION: We concluded that the simulation by using musculoskeletal model may be a useful mean to predict and recover musculoskeletal-related diseases, and analyze complicated experiment such as clash condition.

Isokinetic Muscle Strength and Clinical Evaluation of the Knee Following Arthroscopic Menisectomy / 대한정형외과학회잡지

PURPOSE: Postoperative strength of knee flexor and extensor, and functional evaluation after arthroscopic menisectomy of the knee was evaluated objectively at the time of returning to daily life. MATERIALS AND METHODS: The 31 knees (29 patients) had meniscal injuries without associated ligament injury. The muscle strength was tested with Cybex 340 isokinetic dynamometer preoperatively and at 2, 4, 6, 10 weeks postoperatively. Clinical evaluation by Lysholm scoring system was also done simultaneously. The statistical analysis was evaluated by repeated measures of ANOVA. RESULTS: Muscle strength of extensor (quadriceps) was abruptly decreased to about 45% torque of the preoperative level at postop 2 weeks, but slowly increased to about 90% torque at 10 weeks in 90 degree/sec and 180 degree/sec exercise. The flexor strength was also a little bit decreased at post-op 2 weeks, slowly increased to about 120%-150% torque of preoperative level in 90 degree/sec and 180 degree/sec exercise at post-op 10 weeks. The clinical evaluation by Lysholm scale showed 45 points at postop 2 weeks and slowly improved to 80 points at post-op 10 weeks. CONCLUSIONS: Muscle weakness of knee extensor and flexor remained in isokinetic test at post-op 4-6 weeks. The recovery rate for weakness of hamstrings was faster than quadriceps. The rehabilitation of quadriceps should be accentuated in the prevention of knee injury due to muscle weakness.

Evaluation of Muscle Strength Using Isokinetic Testing and Functional Result after Total Knee Arthroplasty / 대한정형외과학회잡지

PURPOSE: Objective measurements of knee of flexor and extensor strength using isokinetic equipment and function after total knee arthroplasty (TKA) were evaluated until postoperative 12 months. MATERIALS AND METHODS: The control group constituted of 15 persons who were of same age and weight without knee problems. Most of the patients (70%) were operated on both knees simultaneously. The patient group consisted of constituted with 20 patients (34 cases). Isokinetic testing (Cybex) of knee flexor and extensor strength of knee and functional evaluation by HSS score was performed preoperatively and at 3, 6, 12 months postoperatively. RESULTS: The peak torque of the knee extensor and flexor muscle in the patient group was decreased by 17-41% compared to the control group. Especially, the peak torque of extensor was more decreased than flexor muscles. At postoperative 12 months, the peak-torque values of hamstring and quadriceps were able to attain the same strength levels of the preoperative knee. According to the grade of the Hospital for Special Surgery knee rating scales by Insall, 28 cases (82 %) in the patient group could obtain good result at postoperative one year. CONCLUSIONS: Exercises to increase the strength of extensor should be emphasized in the rehabilitation programs after TKA

Torque Curves and Heart Rate Responses to Isometric, Eccentric and Concentric Isokinetic Exercises of the Knee and Elbow Joints

OBJECTIVE: To investigate the torque curves and heart rate responses to isometric, eccentric and concentric isokinetic exercises with a maximal voluntary contraction of the right knee and elbow joints in 30 healthy men(26.6+/-2.2 years). METHOD: Subjected performed the eccentric and concentric isokinetic exercises with 10 repetitions at 60o/sec, while performing the isometric exercises at a joint angle of 60 degrees for the same period of time with Cybex 6000. Peak torque, angle of peak torque, and total work were measured and the flexor-to-extensor ratios of peak torque were calculated. Heart rates were recorded simultaneously at rest and immediately after the exercise, and the time required to return to the resting heart rate level was also recorded for each exercise session. RESULTS: Peak torque and total work for the eccentric exercise were significantly higher than those for the concentric exercise(p<0.01) of the knee and elbow joints. Eccentric peak torques for flexors and extensors of the knee joint occurred at a significantly longer muscle length than the concentric peak torques(p<0.01). Flexor-to-extensor ratios of a peak torque of the knee joint between the eccentric and concentric isokinetic exercises did not show a significant difference. Torques at a joint angle of 60 degrees were highest in the eccentric isokinetic exercise, followed in the order by isometric, and then concentric isokinetic exercises of the knee joint(p<0.01), and concentric torque at a joint angle of 60 degrees was significantly lower than those of the eccentric and isometric exercises of the elbow joint. The increase in heart rate and the time of returning to the resting heart rate level were independent of the size of the contracting muscle mass and the types of exercise. The increment ratio for the heart rate was 70.4+/-23.6%. CONCLUSION: In conclusion, the response of heart rate to the exercise is not influenced by the contracting muscle mass or the types of exercise in a short duration of maximal voluntary contraction, implying that special precautionary measures are not required for the isometric, eccentric and concentric isokinetic exercises.

Effects of Muscle Fatigue on Knee Proprioception

OBJECTIVE: To determine whether muscle fatigue affects knee joint proprioception. METHOD: Thirty healthy subjects (18 male and 12 female) with an average age of 22.1 years were selected for this study. Angular errors were measured to test propriocetive function in the knee joint. In a sitting position, the subject's dominant leg was passively positioned to the 45degrees knee flexion stimulus point for 2~4 second, while the subject concentrated on this position, the leg was passively returned to the 90o flexion position, afterward the subject was asked to duplicate the stimulus point actively. The difference, in degrees between the stimulus point and the reproduced point is an angular error. All subjects were blindfolded and underwent proprioception measurement before and after the muscle fatigue. Isokinetic exercises performed at 180 degree/sec on the Cybex Orthotron II(Cybex, a division of Lumex, Inc. USA) were used to induce the muscle fatigue. All subjects performed an isokinetic exercise with their dominant leg. Exercise was continued until 50% of the initial peak torque was reached. When the subjects were fatigued to less than 50% of the initial peak torque, the isokinetic exercises were discontinued. Then we immediately retested the proprioception using the same method. RESULTS: The mean and standard deviation of the angular error increased from 2.79+/-1.17degrees to 6.40+/-3.42degrees after muscle fatigue. CONCLUSION: The proprioception significantly decreased after the muscle fatigue(p<0.001). This result suggests that the muscle fatigue must be considered when an injured professional athlete a patient with fatigable disease is set in a rehabilitation program. Further studies are required to determine the physiological mechanisms of the role of muscle fatigue for the decreasing proprioception.

THE EXAMINATION OF TRAINING CONDITIONS CONCEWRNING INCREASE IN THIGH MUSCLE USING ISOKINETIC EXERCISE / 体力科学

The effect of isokinetic training was investigated for the strength development in the thigh muscles under various training conditions. Thirty one males from healthy high-school students served as subjects of this study. Training was performed using a Cybex II machine with two kinds of repeated load conditions (number of repetitions, cf. Table 1 & Fig. 1) at to different rotational speeds (30 degrees and 180 degrees per second) . The training was done three times per week for nine weeks. The effects of training were evaluated on the basis of the amount of increase in the strength during knee flexion and extension.<BR>The results were summarized as follows :<BR>1) The effect of training became apparent most swiftly under the rotational speed of 180 degrees per second and light load of repetitions, respectively.<BR>2) The largest increase in the muscluar strength was observed for the group with training speed of 180 degrees per second and hevey load of repetitions, respectively.<BR>3) The strength increased periodically every four or five week for all conditions.