[ effect of shoulder resistance training on isometric strength of the neck extensor muscles]

Neck pain is an important public health care problem in modern societies, and proper and effective training programs are required for its prevention and treatment. The purpose of this study was to determine the effect of shoulder-abduction resistance trainings on isometric strength of the neck extensor muscles. In this study, a total of 28 healthy women [20-25 years of age], were randomly divided into two groups of shoulder-abduction resistance exercises [n=14] and control [n=14], who performed active range of motion exercises [AROM]. Both groups performed exercises 3 days/week for 10 weeks. In both groups, isometric strength of neck muscles was measured before and after the intervention period using an isometric neck muscle strength measurement device. Data were analyzed by independent and paired t-tests. The strength of the neck extensor muscles in the case group was 72.69 +/- 15.82, which was significantly higher in comparison with the control group, 52.68 +/- 14.20 [p<0.001]. The results of this study showed that shoulder-abduction resistance exercises are effective in increasing isometric strength of the neck extensor muscles

[Genu varum deformity may increase postural sway and falling risk]

Any disturbance in balance control procedures may increase the risk of injury during sport activities. Knee deformities such as genu valgum and genu varum may perturb the line of gravity passing the lower limb joints and so disturb dynamic and static balance indices. This study was designed to investigate the effects of genu valgum and genu varum deformity on the static and dynamic balance indices. A total of 90 non-athletic female university students were assigned in one of the three experimental groups; normal knee [n=30], genu varum [n=30] and genu valgum [n=30], according to their knee conditions. Static and dynamic overall stability index [OSI], anterior-posterior stability index [APSI], medial-lateral stability index [MLSI] and falling risk were evaluated three times by Biodex balance system, and the average of each index were recorded. No significant difference was seen between groups in term of dynamic and static OSI and APSI, while significant lower stability was found in the genu varum group compared to normal groups in term of dynamic and static MLSI [p<0.05]. A significant increased in falling risk was also seen in genu varum group, compared to the normal group [p<0.05]. The results showed that mechanical disturbance due to the genu varum deformity may perturb the medial-lateral balance indices in both static and dynamic situations. This may indicate that genu varum deformity may increase the normal postural sway in the medial lateral direction and increase falling risk as well

Inhibition of short latency reflex linking the pretibial muscles to quadriceps motoneurones during stance to swing transition in humans

The modulation of short latency reflex linking the pretibial to quadriceps muscle [CPQ reflex] was investigated in seven subjects during walking on a treadmill at the stance to swing transition period. The intensity of quadriceps [Q] EMG was increased throughout the gait cycle by using a modified knee orthosis. Pairs of spring were added to the orthosis to produce different levels of .muscular activity in Q during the midstance, transition period and terminal swing phase of gait. Electrical stimulation was applied to the common peroneal nerve [CRN] at these three instants of gait. The peak to peak amplitude of CPQ reflex was significantly increased with escalation of background EMG in Q during midstance [p<0.015] and terminal swing [p<0.04]. At the transition period however, despite significant increase in the Q activity no responses was evoked. The results were indicative of an active inhibition of the reflex pathway during transition period. This inhibition could help the unloading of the limb that is necessary for the initiation of the swing phase