Abstract:

BACKGROUND: The quadriceps strength of patients with osteoporosis and sarcopenia is significantly reduced, which can further reduce the function of the knee joint, affect the function of the lower limbs and even lead to a decrease in whole-body coordination. It is speculated that a reasonable quadriceps training program and personalized guidance are beneficial to the recovery of knee joint function in patients with osteoporosis and sarcopenia.

OBJECTIVE: To observe the effect of short-term moderate-intensity resistance rehabilitation training on the mass and function of the quadriceps and knee joint function in patients with osteoporosis and sarcopenia. 
METHODS: Using the integrated physical examination and rehabilitation model, 375 patients with osteoporosis and sarcopenia were screened at the Health Management Center of Shanghai Public Health Clinical Center. They underwent 12 weeks of combined/comprehensive exercise rehabilitation based on resistance exercise, including quadriceps resistance isotonic and isometric contraction training twice a week (3-5 sets each time, 10-15 minutes per set) and aerobic exercise/balance exercise two or three times a week (30 minutes each time). Assessments and data collection were performed before rehabilitation training, 12 weeks after rehabilitation training, and at follow-up 12 weeks after stopping rehabilitation training, mainly including knee joint range of motion and proprioception, quadriceps muscle strength, and cross-sectional area (magnetic resonance imaging results), pain, knee joint function (Hospital for Special Surgery score) and walking function (“up-and-go” time and 6 m pace test results) as well as the patient's psychological status assessment.  
RESULTS AND CONCLUSION: All 375 patients completed 12 weeks of rehabilitation training and 12 weeks of follow-up without any adverse events. (1) Compared with before training, the patients’ gait speed and knee range of motion increased significantly after 12 weeks of rehabilitation training (P < 0.01), the time of “stand-to-walk” decreased (P < 0.01), and the proprioception of the knee joint and the strength of the quadriceps femoris were significantly improved (P < 0.01); and at the follow-up visit 12 weeks after stopping training, the above indicators and functions of the patients were well maintained (P > 0.05). (2) Magnetic resonance imaging results showed that the effective cross-sectional area of the quadriceps femoris did not improve significantly after 12 weeks of rehabilitation training (P > 0.05); but the Hospital for Special Surgery score of knee joint function increased significantly (P < 0.01), and the visual analog pain scale score decreased significantly (P < 0.01), suggesting that this may be related to the improvement of quadriceps femoris quality by resistance rehabilitation training. (3) The results of the Hospital Anxiety and Depression Scale score showed that the anxiety and depression scores of the patients continued to decrease, both at 12 weeks of rehabilitation training and at 12 weeks after stopping training (P < 0.01). It is suggested that resistance rehabilitation training of the quadriceps can help patients with osteoporosis and sarcopenia to restore quadriceps muscle strength, increase range of motion, improve proprioception and joint stability, thereby enhancing knee joint function, reducing pain, improving depression and anxiety, and to a certain extent promoting the coordinated recovery of the musculoskeletal system.

Key words: sarcopenia, osteoporosis, resistance training, rehabilitation training, quadriceps, knee joint function, walking, muscle strength