1.Definition The resistance load acting on the muscles is constant during training to produce joint movements, thereby improving dynamic muscle strength or muscle endurance. Isotonic muscle strength training includes centripetal training and centrifugal training. The muscle is actively shortened so that the two ends are close to each other for centripetal muscle training; the muscle is gradually lengthened during contraction so that the two ends are separated from each other for centrifugal muscle training. 2, indications and contraindications 1) Indications: muscle disuse atrophy caused by braking, reduced movement or other reasons, muscle atrophy caused by muscle lesions, muscle dysfunction caused by neuropathy, muscle weakness caused by joint disease or injury, muscle dysfunction, muscle strength training for healthy people or athletes. 2) Contraindications: joint instability, new fracture or fracture not completely healed, acute inflammation or infection (redness and swelling), severe pain and hematoma during joint activity or muscle extension, bone and joint tumor, poor general condition and unstable condition. 3.Equipment and appliances sandbags, dumbbells, elastic resistance devices, wall tensioners, pulley systems, isotonic moment arm components such as quadriceps trainers, variable resistance devices or special muscle trainers, etc. 4.Operation method and steps 1）Patients in appropriate position, therapist select good guidance position. Choose the appropriate resistance device, fix the position and resistance device, and ask the patient to complete the corresponding sports action. (2) Determine the goal of muscle strength training, select the appropriate exercise intensity: strengthen muscle strength for the purpose: progressive resistance training method as an example, first determine the maximum load of 10 repetitions of exercise, called 10RM value. Train with 1/2 exercise intensity of 10RM, repeat 10 times with 30 seconds interval; then repeat 10 times with 75% exercise intensity of 10RM with 30 seconds interval; then repeat 100% exercise intensity of 10RM as many times as possible, and after 2-3 weeks, adjust the amount of 10RM appropriately according to the patient’s condition; training frequency 1 time/day, 3-4 times a week for several weeks; develop muscle For the purpose of developing muscle endurance: use 50% of the amount of 10RM as the training intensity, each group of exercises 10-20 times, repeat 3 groups, each group interval 1 minute. Repetitive pulling exercises can also be performed with an elastic band of appropriate length and resistance factor. One end of the elastic band is fixed on the bed frame or other fixed object, and the elastic band is repeatedly pulled until muscle fatigue, 1 time/day, 3 to 5 days per week. 5, precautions 1) For patients with joint injury, osteoporosis or serious cardiovascular disorders, 10RM test and maximum resistance training are not recommended. 2) Pay attention to identify the amount of exercise control to enhance muscle strength or develop muscle endurance. When developing muscle endurance and increasing exercise load, light resistance exercises that extend exercise time and increase the number of exercises should be selected. 3) Strictly observe the cardiovascular response during isotonic muscle training, especially during centrifugal exercise. 4) Other considerations refer to “unarmed muscle training”.