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The purpose of this study was to analyse the reproducibility of isokinetic single-joint (knee and ankle) and multi-joint (leg-press configuration) strength findings in healthy athletes and a group of athletes with chronic unilateral tendon injuries at the lower limb, over a clinically meaningful time interval of 8 weeks. Concentric and eccentric strength performance capacity of knee extensors/flexors, ankle dorsi-/plantarflexors as well as the extensors of the total lower limb was assessed twice in 19 healthy (H) and 10 injured (I) athletes. Calculation of ICC, standard error of measurement SEM, Bland and Altman's 95% limits of agreement and Test-Retest Variability (TRV) served as main outcome variables. The results showed a small systematic bias and random error [mean bias: 3.25 ± 4.02 (H) 4.25 ± 4.56 (I); TRV 12.34 ± 10.20% (H) 14.27 ± 9.42% (I)] except for plantarflexion measurements and the eccentric mode of the total lower limb strength in injured athletes (TRV 20%). The present findings delineate clinically relevant cutoff values in the evaluation of valid intervention effects of strength training and rehabilitation in healthy athletes and athletes suffering from tendon-related injuries. [ABSTRACT FROM AUTHOR]

It still remains unclear whether muscular activity on the treadmill (T) differs compared to overground (O) running. The purpose of this study was therefore to examine possible differences in muscular activation between T and O. 14 healthy runners were analyzed in a neutral running shoe at 12 km·h{-1} on a treadmill and in a field test. Muscular activity (EMG) of the tibialis anterior, peroneus longus, and soleus were measured. Time and amplitude quantities were assessed during the gait cycle. The EMG of the peroneus longus exhibited a later onset, a later maximum and shorter total time of activation (p<0.05) in O. The soleus showed a higher amplitudes in O during the push-off phase (p<0.05). Altered peroneus longus activity may indicate its role as an ankle stabilizer and demonstrates a compensatory response due to changing mechanical conditions. Weaker amplitudes of the soleus in the push-off during T suggest adaptation to the movement of the treadmill belt, and/or changes in load receptor input. Differences in muscle activity between T and O running must thus be taken into consideration in studies of neuromuscular control of movement. [ABSTRACT FROM AUTHOR]

Differences in lower extremity movement characteristics are stated as a reason for overuse injuries. The causal assignment of biomechanical quantities to the onset of complaints is still subject of debate in gait analysis. The purpose of this study was therefore to compare biomechanical gait characteristics by means of plantar pressure distribution (PPD), EMG and ground reaction forces (GRF) in healthy runners and in runners with chronic Achilles tendon complaints (AT). Fourteen healthy runners and 8 runners with AT were examined at 12 km/h. Surface EMG, in-shoe PPD and GRFs were evaluated on a treadmill mounted on force transducers. Subjects ran barefoot and with a reference shoe in random order. EMG time and amplitude quantities, characteristics of the path of the center of pressure (CoP), vertical and a-p forces and impulses were extracted. In AT no differences in CoP-characteristics between barefoot and reference shoe were observed, compared to corresponding significant differences in the control group. Compared to the AT group, the control subjects had a higher activity EMG-amplitudes in the extensor loop during weight acceptance phase, a higher braking impulse and a lower pushing impulse. It is thus concluded that healthy runners differ from AT patients in terms of movement characteristics especially in running. [ABSTRACT FROM AUTHOR]

Muscular balance appears to be decisive for dynamic shoulder stability, since passive stabilizers do not take effect until the end of range of motion in order to not limit joint mobility. Changes in strength relationships are frequently viewed as one of the causes of shoulder pathologies. However, objective quantification of reciprocal strength relationships is difficult. In particular, the influence of movement velocity on the strength ratios during the test has not been clarified. Determination of the strength relationships of reciprocal muscle groups (quotient of maximum torques) was performed on a total of 166 untrained men (M) and 83 untrained women (F) for extension/flexion, abduction/adduction and rotation movements of the shoulder. Moreover, differentiation was made by various working modes and movement velocities (isometric at various angle positions, concentric at 60°/s and 180°/s, eccentric at 60°/s and 120°/s). The results show a decreasing order of strength relationships: Abduction/Adduction > Flexion/Extension > External/Internal rotation. In spite of marked differences in absolute values, no differences were noted among the contraction modes (isometric, concentric, eccentric) or movement velocities (p>0.05). A slightly reduced ratio of rotational movements in concentric mode was the only conspicuous finding. Unlike isokinetically-determined absolute torque values, a relevant velocity-dependence must not be expected with respect to reciprocal strength relationships of the shoulder muscles. A different (neuro)-muscular structure of the muscle groups involved with a corresponding effect on the strength-performance ratio thus does not appear to be present or cannot be detected in isokinetic tests. However, further research is warranted regarding the effect of the various associated factors (e.g. stabilization) on the reliability and validity of isokinetic findings relating to this specific joint-muscles system. [ABSTRACT FROM AUTHOR]

Deals with a study which analyzed muscular endurance capacity in runners with unilateral Achilles tendon complaints. Methods used in the study; Results of the study.

Deals with a study which investigated objective differences in electromyographic pattern and isokinetic peak torque after four weeks of physiotherapy with special focus on eccentric training and treatment with individual orthopaedic insoles. Methods used in the study; Results of the study.