Effect of Eccentric Exercises on Knee Function and Neuromuscular Control of Patellofemoral Pain Syndrome / 中国康复理论与实践

Objective:To investigate the effect of eccentric exercise training on knee function and neuromuscular control in patients with patellofemoral pain syndrome. Methods:From September, 2016 to September, 2019, 39 outpatients with patellofemoral pain syndrome visiting our hospital were randomly divided into control group (n = 19) and experimental group (n = 20). Both groups received routine rehabilitation, while the experimental group received eccentric training of quadriceps femoris in addition, for eight weeks. They were assessed with Visual Analogue Scale (VAS) of pain, Lysholm score, while the acceleration time was measured with Isokinetic Testing and Training System, and stability index with Dynamic Balance Tester. Results:The VAS score, acceleration time of all the muscles, and overall, anterior-posterior and medial-lateral stability indexes decreased (t > 2.521, P < 0.05), and the Lysholm score increased (|t| > 13.628, P < 0.001) in both groups after treatment, while the VAS score, acceleration time of all the muscles, overall and anterior-posterior stability indexes were less (|t| > 2.174, P < 0.05), and the Lysholm score was more (t = 11.947, P < 0.001) in the experimental group than in the control group. Conclusion:Eccentric exercise training of quadriceps femoris is effective on pain, knee function and neuromuscular control for patients with patellofemoral pain syndrome.

Efeito da massagem clássica na percepção subjetiva de dor, edema, amplitude articular e força máxima após dor muscular tardia induzida pelo exercício / Effect of classical massage on subjective perceived soreness, edema, range of motion and maximum strength after delayed onset muscle soreness induced by exercise

O treino de força com cargas elevadas tem induzido indivíduos a apresentarem sintomas de dano muscular que incluem a dor muscular tardia. Na tentativa de diminuir sintomas e desconforto da DOMS, estratégias têm sido utilizadas, entre elas, a massagem. O objetivo do presente estudo foi verificar os efeitos da massagem clássica na percepção subjetiva de dor (DOMS), circunferência do braço (CIR), amplitude de movimento (ADM) e força máxima (1RM) após protocolo para indução de DOMS. Para isso, 18 adultos jovens saudáveis do gênero masculino foram divididos em três grupos (G1 = massagem; G2 = protocolo; G3 = protocolo + massagem) equalizados pelo teste de uma força máxima de flexão de cotovelo no banco Scott. O protocolo de indução de DOMS consistiu de 30 ações excêntricas musculares supramáximas (seis séries de cinco repetições a 110 por cento de 1RM). A massagem foi realizada no grupo G3 imediatamente após o protocolo durante seis minutos. As variáveis dependentes (DOMS, CIR, ADM) foram avaliadas 24, 48, 72 e 96 horas após o protocolo, enquanto a força máxima, apenas após 48 e 96 horas. Os resultados indicaram aumento na DOMS e diminuição na ADM e 1RM, similar aos de outros estudos que utilizaram protocolos semelhantes. No entanto, não houve diferenças entre os grupos G2 e G3 em nenhuma das variáveis analisadas. Pode-se concluir que com esse design experimental o protocolo utilizado foi eficaz para provocar as alterações nas variáveis analisadas e a massagem não causou nenhum benefício na recuperação das funções musculares nem na percepção subjetiva de dor.

Heavy resistance training induces to symptoms of muscle damage which include delayed onset muscle soreness (DOMS). Some strategies (i.e. massage) have been used to attenuate these symptoms and to reduce discomfort associated with DOMS. This study aimed to investigate the effects of classical massage on DOMS perception, limb girth (CIR), range of motion (ADM) and maximum strength performance (1-RM) after a muscle damage protocol. Eighteen males were divided into three groups (G1= massage-only, G2= protocol-only, G3= protocol + massage) according to their 1-RM values. DOMS-inducing protocol consisted of 30 supramaximal eccentric contractions (6 sets of 5 repetitions at 110 percent 1RM). Immediately after the protocol, classical massage was performed in G3 for 6 minutes. DOMS, CIR, ADM were assessed 24, 48, 72 and 96 hours after the muscle damage protocol, and maximum strength was evaluated only after 48 and 96 hours. Results showed increase in DOMS and reduction in ADM and 1-RM values, in agreement with other studies using similar procedures. However, there was no difference between G2 and G3 in any of the assessed variables. It can be concluded that the muscle damage protocol used in this study was effective in causing alteration in the dependent variables observed. However, classical massage was not effective to minimize the symptoms associated to exercise induced muscle damage.

Effect of muscle contraction type and speed on tissue oxygen dynamics in the M. vastus medialis during repeated knee extension exercise / 体力科学

The purpose of this study was to analyze the relationship between activity pattern and temporal changes in the oxygen dynamics of human femoral medial vastus muscles. Oxygen dynamics were evaluated from the surface of the body by near-infrared spectroscopy (NIRS) . Arterial occlusion tests were performed in the femoral region at a cuff pressure of 300 mmHg. Exercise type and speed were controlled by CYBEX 6000. The exercise types examined were concentric contraction (CON) and eccentric contraction (ECC) . The 3 angular velocities of 90, 120 and 180 degrees were used as the exercise speeds. Exercise was performed continuously 60 times at maximum effort. The subjects were 7 healthy males with a mean age of 19.6±0.5 years. A transient decrease in oxygen concentration was observed during circulatory occlusion ; and rapid hyperemia occurred immediately after the removal of pressure. Oxygen concentration peaked above the control level and then returned to the initial level. In the CON exercise, the initial decrease in oxygen concentration was the largest at CON 90, and a gradual increase in oxygen concentration was clearly observed during exercise. In the recovery stage, after exercise at CON 90, 120 and 180, oxygen concentration exceeded the control level before exercise, then peaked and returned to the initial level. In the ECC exercise, an initial decrease in oxygen concentration was similar to that in the CON exercise, but a gradual increase in oxygen concentration was not observed during the exercise ; nor did oxygen concentration exceed the control level in the recovery stage after the exercise.<BR>These results indicate that an increase in oxygen level after the removal of arterial occlusion, during and after the CON exercise was much higher than the control level before the exercise, sug-gesting the involvement of reactive hyperemia and exercise hyperemia.

Quantitative Analysis of Isotonic Exercise Using Virtual Reality Motion Analysis System(VRMAS)

Isotonic exercise occurs when the tension or torque generated by a muscle is constant throughout the movement. In practice it is very difficult to maintain the tension constant. Evaluation of isotonic exercise should include the works of concentric and eccentric contraction and the changes in tension and torque during joint motion. However, optimal evaluation tools for isotonic exercise has yet to be developed. We authors, used virtual reality motion analysis system(VRMAS) which was codeveloped by us and EMG system(Cardwell Excel). Healthy male adult subjects(n=10) were recruited from hospital personnel. After dominant upper arm and trunk of each subject was fixed with velcro, he was instructed to repeat flexion and extension of his dominant elbow grasping dumbell (9 kg) in hand with maximal velocity as possible as can until the point of exhaustion. We measured the elbow angle, the angular velocity, torque, power, total work and the work of concentric and eccentric contraction during exercise. The results were as follows: there were four distinct elbow flexor muscle contractions during flexion and extension of the elbow with the first and the second contractions during concentric contraction and the third and the fourth contractions during eccentric contraction. Between the peaks of contraction, motion was maintained due to the momentum that was generated. Of the ten subjects, seven had higher concentric work than eccentric work with the eccentric work being higher in the remaining three. But there was no statistic significance between the works of concentric contraction and eccentric contraction(p>0.05). The biggest work was observed in the fourth contraction, while the third contraction showed the least work(p<.05). In conclusion, there were four distinct muscle contractions during elbow isotonic exercise and the works of each muscle contraction were different. This result is contrary to the definition of isotonic exercise. This study also shows that the VRMAS could be a very useful evaluation tool for several types of isotonic exercise.