The results indicate that muscle activation strategy and quality of force control were significantly affected in adults with GJH during knee flexion, whereas only muscle activation strategy was affected in children with GJH.

Visceral adipose tissue is an immunogenic tissue, which turns detrimental during obesity by activation of proinflammatory macrophages. During aging, chronic inflammation increases proportional to visceral adipose tissue (VAT) mass and associates with escalating morbidity and mortality. Here, we utilize a mouse model to investigate the inflammatory status of visceral adipose tissue in lean aging mice and assess the effects of exercise training interventions. We randomized adult (11 months; n = 21) and old (23 months; n = 27) mice to resistance training (RT) or endurance training (ET), or to a sedentary control group (S). Strikingly, we observed an anti-inflammatory phenotype in the old mice, consisting of higher accumulation of M2 macrophages and IL-10 expression, compared to the adult mice. In concordance, old mice also had less VAT mass and smaller adipocytes compared to adult mice. In both age groups, exercise training enhanced the anti-inflammatory phenotype and increased PGC1-α mRNA expression. Intriguingly, the brown adipose tissue marker UCP1 was modestly higher in old mice, while remained unchanged by the intervention. In conclusion, in the absence of obesity, visceral adipose tissue possesses a pronounced anti-inflammatory phenotype during aging which is further enhanced by exercise.

Olesen AT, Jensen BR, Uhlendorf TL, Cohen RW, Baan GC, Maas H. Muscle-specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat. J Appl Physiol 117: 989-997, 2014. First published September 4, 2014 doi:10.1152/japplphysiol.00587.2014.-The purpose of the present study was to investigate muscle mechanical properties and mechanical interaction between muscles in the lower hindlimb of the spastic mutant rat. Length-force characteristics of gastrocnemius (GA), soleus (SO), and plantaris (PL) were assessed in anesthetized spastic and normally developed Han-Wistar rats. In addition, the extent of epimuscular myofascial force transmission between synergistic GA, SO, and PL, as well as between the calf muscles and antagonistic tibialis anterior (TA), was investigated. Active length-force curves of spastic GA and PL were narrower with a reduced maximal active force. In contrast, active length-force characteristics of spastic SO were similar to those of controls. In reference position (90°ankle and knee angle), higher resistance to ankle dorsiflexion and increased passive stiffness was found for the spastic calf muscle group. At optimum length, passive stiffness and passive force of spastic GA were decreased, whereas those of spastic SO were increased. No mechanical interaction between the calf muscles and TA was found. As GA was lengthened, force from SO and PL declined despite a constant muscle-tendon unit length of SO and PL. However, the extent of this interaction was not different in spastic rats. In conclusion, the effects of spasticity on length-force characteristics were muscle specific. The changes observed for GA and PL muscles are consistent with the changes in limb mechanics reported for human patients. Our results indicate that altered mechanics in spastic rats cannot be attributed to differences in mechanical interaction, but originate from individual muscular structures. muscle spasticity; mechanical properties; myofascial force transmission; muscle stiffness MUSCLE SPASTICITY HAS BEEN defined as a "velocity-depended resistance to stretch" (24) and arises secondary to upper motoneuron lesions with cerebral palsy and stroke as the most common examples (12). Individuals suffering from spasticity typically experience muscle weakness, enhanced joint stiffness, increased muscle tone, reduced range of joint motion, increased antagonistic co-contraction, and exaggerated reflexes (1,3,6,12,13,32,41,48). These effects severely impair the ability to perform daily activities, and treatment is often needed.To asses whether some of these symptoms are related to altered mechanical properties of muscle-tendon units (MTUs), passive and active length-force characteristics have been estimated as joint moment as a function of gastrocnemius (GA) fascicle length. Spastic GA was found to be stiffer than normally developed in such studies (2, 3). The active lengthforce curve of the spastic GA was narrower and the optimum length was shifted to a shorter fascicle length than in normally deve...