Advance in Isokinetic Concept for Rehabilitation Medicine (review) / 中国康复理论与实践

The isokinetic muscle strength test and isokinetic training are considered to be one of the most important practical techniques for muscle assessment and training. This paper reviewed the specific applications of isokinetic concept in rehabilitation assessment and rehabilitation treatment in recent years, introduced the effects of isokinetic concept on neurological diseases, orthopaedic diseases and other diseases, briefly analyzed the related mechanism and summarized its advantages.

Unilateral and ipsilateral strength asymmetries in elite youth soccer players with respect to muscle group and limb dominance / Asimetría de fuerzas unilateral e ipsilateral en jugadores de fútbol de elite juveniles con respecto al grupo muscular y a la dominancia de miembros

The purpose of study was to identify the presence of strength asymmetries (SA) in young elite soccer players in relation to muscle group (knee extensors (KE) and flexors (KF)) and limb preference (dominant vs. non-dominant limb). Forty-one U16 national team soccer players (mean age 15.7±0.3 years, body height 177.9±6.6 cm, body weight 68.2±7.9 kg) participated in this study. Assessments were performed on a Cybex Humac Norm isokinetic dynamometer in concentric contraction. We noted the degree of SAs in the bilateral ratio of quadriceps and hamstrings and in the ipsilateral ratio of the dominant (DL) and non-dominant (NL) legs. Bilateral deficits of KFs were higher (9.02­12.61 %) than those of KFs (6.32­7.15 %). The percentage of SA (>10 %) in knee extensors was 19.5­31.7 %. The percentage of SA (>10 %) in knee flexors was 36.6­51.2 %. At the lowest velocity, there was asignificantly higher prevalence of SAs in KFs than in KEs (c2= 4.11, p<.05). The ipsilateral ratio was lowest at the lowest velocity regardless of limb dominance (DL: 58.95­63.27 %, NL: 56.58­60.11 %). At each velocity, the percentage of SA was higher for the non-dominant limb (12.2­24.4 %) than for the dominant one (4.9­14.6 %). Despite these differences, we did not find any significantly higher prevalence of SA in the non-dominant limb than in the dominant one (c2= .35­2.04, p>.05). The results of the study suggest that more than 73.2 % of players have at least one SA. More attention should be paid to knee flexors, where a higher percentage of strength asymmetries were observed; furthermore, a higher percentage of strength asymmetry was seen in the non-dominant lower limb.

El objetivo de este estudio fue identificar la presencia de asimetría de fuerzas (AF) en jóvenes jugadores de fútbol de élite en relación con el grupo de músculos extensores de la rodilla (ER) y flexores (FR) y la preferencia de los miembros (miembro dominante frente al miembro no dominante). Participaron en este estudio 41 jugadores sub-16 del equipo nacional de fútbol (edad media de 15,7±0,3 años; altura 177,9 ± 6,6 cm; peso corporal 68,2±7,9 kg). Las evaluaciones se llevaron a cabo en un dinamómetro isocinético Cybex Humac Norm en contracción concéntrica. Se registró el grado de AF en la relación bilateral de los músculos cuádriceps y los tendones y en la relación ipsilateral del miembro dominante (MD) y el miembro no dominante (MND). Los déficits bilaterales fueron más altos en FR (9,02 a 12,61 %) que en ER (6,32-7,15 %). El porcentaje de AF (> 10 %) en los músculos extensores de la rodilla fue de 19,5 a 31,7 %. El porcentaje de AF (> 10 %) en los músculos flexores de la rodilla fue de 36,6 a 51,2 %. A la velocidad más baja, había una mayor prevalencia de AF en FR que en ER (c2 = 4.11, p <0,05). La relación ipsilateral fue la más baja a la velocidad más baja, independientemente de la dominancia de los miembros (MD: 58,95 a 63,27 %, MND: 56, 58-60, 11 %). En cada velocidad, el porcentaje de AF fue mayor para el miembro no dominante (12,2 a 24,4 %) que para el miembro dominante (4,9 a 14,6 %). A pesar de estas diferencias, no hemos encontrado ningún prevalencia significativamente mayor de AF en el miembro no dominante en comparación al miembro dominante (c2 = 0,35 a 2,04, p> 0,05). Los resultados del estudio sugieren que más de 73,2 % de los jugadores tienen al menos una AF. Más se debe prestar atención a los músculos flexores de la rodilla, donde se observó un mayor porcentaje de asimetría de fuerzas. Por otra parte, un mayor porcentaje de asimetría de fuerzas se observó en el miembro inferior no dominante.

Differences in muscle strength after ACL reconstruction do not influence cardiorespiratory responses to isometabolic exercise

Objectives: To investigate whether the muscle strength decrease that follows anterior cruciate ligament (ACL) reconstruction would lead to different cardiorespiratory adjustments during dynamic exercise. Method: Eighteen active male subjects were submitted to isokinetic evaluation of knee flexor and extensor muscles four months after ACL surgery. Thigh circumference was also measured and an incremental unilateral cardiopulmonary exercise test was performed separately for both involved and uninvolved lower limbs in order to compare heart rate, oxygen consumption, minute ventilation, and ventilatory pattern (breath rate, tidal volume, inspiratory time, expiratory time, tidal volume/inspiratory time) at three different workloads (moderate, anaerobic threshold, and maximal). Results: There was a significant difference between isokinetic extensor peak torque measured in the involved (116.5±29.1 Nm) and uninvolved (220.8±40.4 Nm) limbs, p=0.000. Isokinetic flexor peak torque was also lower in the involved limb than in the uninvolved limb (107.8±15.4 and 132.5±26.3 Nm, p=0.004, respectively). Lower values were also found in involved thigh circumference as compared with uninvolved limb (46.9±4.3 and 48.5±3.9 cm, p=0.005, respectively). No differences were found between the lower limbs in any of the variables of the incremental cardiopulmonary tests at all exercise intensities. Conclusions: Our findings indicate that, four months after ACL surgery, there is a significant deficit in isokinetic strength in the involved limb, but these differences in muscle strength requirement do not produce differences in the cardiorespiratory adjustments to exercise. Based on the hypotheses from the literature which explain the differences in the physiological responses to exercise for different muscle masses, we can deduce that, after 4 months of a rehabilitation program after an ACL reconstruction, individuals probably ...

Isokinetic testing of flexor and extensor torque of knee joint in women handball players / 医用生物力学

Objective To discuss the characteristics of flexor and extensor torque of the knee joint by carrying out isokinetic testing on women handball players in Guangdong Province, and to provide some isokinetic test data for the strength and physical training research on handball players. Methods Flexor and extensor of knee joint in fourteen players from Guangdong provincial handball team were measured by CON-TREX isokinetic testing system. Relative peak torque, hamstring/quadriceps ratio, total work, average power and fatigue index were selected to study the isokinetic characteristics of the women handball players’ knee joint. Independent t tests were employed to compare the results between flexor and extensor. Results For women handball players, at the velocity of 60°/s (low speed test)and 240°/s(high speed test), the relative extensor peak torque value was significantly greater than that of the flexor（P＜0.01）; at the velocity of 240°/s, the hamstring/quadriceps ratio was about 76%; at the velocity of 60°/s,　the total work and average power of the extensor was greater than that of the flexor（P＜0.01）; at the velocity of 240°/s, the total work and average power of the extensor in left knee joint were greater than that of the flexor（P＜0.05）; the range of fatigue index was from 0 to 0.49. Conclusions The maximum strength and speediness strength of extensor was greater than that of the flexor; at the velocity of 240°/s, the hamstring/quadriceps ratio of the knee joint was relatively lower, which showed that the speediness strength of flexor in knee joint was relatively low; the speediness strength and the working capability of the extensor in knee joint was greater than that of the flexor; the fatigue index of extensor and flexor of knee joint was relatively low, which may indicate that the level of strength stamina of extensor and flexor in knee joint was relatively low.

The isometric concentric and eccentric strength of patients with knee osteoarthritis / 中华物理医学与康复杂志

Objective To evaluate the functional changes in the isometric,concentric and eccentric muscle strength of the knee extensors and flexors in patients with knee osteoarthritis,and to explore the relationship among these contractions.Methods A Biodex System-3 isokinetic test system was used to assess the isometric,concentric and eccentric strength of the knee extensors and flexors of the involved and uninvolved limbs of 54 patients suffering from osteoarthritis.Results The strength of the knee extensors and flexors of the involved limbs was significantly less than that of the uninvolved legs in the different contraction modes(P＜0.05).The difference was especially marked in concentric and eccentric contraction at low angular velocity.The hamstrings/quadriceps ratio and the dy- namic control ratio showed abnormalities in the muscle balance of the hamstrings and quadriceps.Conclusion Iso- kinetic testing should be applied and the hamstrings/quadriceps ratio and the dynamic control ratio should be analyzed in evaluating patients with knee osteoarthritis.

A clinic study of trunk muscle strength and lumbar curvature in young patients with low back pain / 中华物理医学与康复杂志

0. 05), TAE of flexors in patients were lower than those in the healthysubjects(P 0. 05 ). F/E in patients were greater than those in healthy subjects(P

Effects of intensified training on muscular strength of the ankle and cross-section surface area of Achilles tendon in soldiers / 解放军医学杂志

Objective The purpose of this study was to evaluate the effects of intensified training on muscular strength of soldiers' ankles and Achilles tendon, and to search for effective training methods through the kinetic study of the ankle joint and cross-sectional area (CSA) measurements of the Achilles tendon. Methods 30 recruits and 30 soldiers enlisted over one year were selected randomly. The recruits underwent an intensified training for eight weeks, and the enlisted soldiers underwent only routine training. The muscular strength of the ankle was tested by CYBEX-6000 isokinetic test system and the cross-sectional area (CSA) of the Achilles tendon was measured in the recruits and the enlisted soldiers before and after the intensified training. Results No difference of CSA of Achilles tendon was found among the recruits before and after the intensified training and the soldiers enlisted over one year (0.64?0.05cm~2、0.67?0.07cm~2、0.65?0.07cm~2) (P=0.698, F=0.361), while the CSA showed a positive correlation with body weight (r=0.446). The isokinetic test results indicated that the muscular strength of the ankle of the recruits was built up obviously after intensified training (P0.05). Conclusion The effects of 8-week intensified training were almost similar to one-year routine training. Enforced training seemed to be able to improve training outcomes in a shorter time. The results that no change in CSA of the Achilles tendon after intensified training indicated that the improvement in ankle muscular strength might be attributed to the moulding reconstruction of tendon function rather than by the enlargement of the tendon.

The change in trunk muscle performance in recruits with low back pain caused by military training and its prevention / 解放军医学杂志

To elucidate the change in trunk muscle performance in patients with low back pain caused by military training. The indices of trunk muscle strength (PT/BW, TAE, F/E, ER), the cross-sectional area of sacrospinalis, the amplitude and the duration of EMG, and the lumbar curvature were measured in recruits with low back pain after military training (n=40)and healthy subjects(n=40).All of the indices were compared between two groups. It was found that except PT/BW and ER of flexors and cross-sectional area of sacrospinalis, there were significant differences between other indices of the patients compared with healthy subjects(P

The effect of 8 weeks intensified and step-by-step training on changes in muscular function of knee flexors and extensors of male recruits to the army / 解放军医学杂志

Objective To evaluate the influence of intensified and step-by-step training on the strength of the knee flexors and extensors in Chinese army male recruits. Methods At the beginning and end of their 8-week endurance training, 160 recruits received isokinetic dynamometer tests for both knees flexors and extensors with the Cybex-6000 isokinetic dynamometer. Results After endurance training, there was a significant increase in the peak torque values, torque acceleration energy, and endurance ratio of both knee flexors at two angular velocities (60 /s,180 /s). Conclusion Eight weeks of recruit intensified and step-by-step training for male recruits is sufficient for increasing muscular strength, explosive force and muscular endurance of knee flexors and extensors.