As not all 10 factors studied were predictive of osteoarthritis, the hypothesis was only partially proven. Preventing further meniscal and chondral damage in patients with anterior cruciate ligament deficiency is critical. Grafting using the hamstring tendons and restoration of quadriceps-to-hamstring strength balance are associated with less osteoarthritis.

Functional stability of the knee is dependent on an intact ligamentous system and the timely and efficient contraction of supporting musculature. The aim of this study was to assess the relationship between muscle strength and functional stability in 31 patients pre-and post-operatively, following a unilateral anterior cruciate ligament rupture. All subjects underwent reconstructive surgery using semitendonosis and gracilis tendons. Isokinetic strength assessment of quadriceps and hamstring muscles was performed at a rate of movement of 6Oo/s and 120°/s. Functional stability was determined by performance during five functional stability tests that included the shuttle run, side step, carioca, single and triple hop tests. Pearson's correlation coefficient statistics were applied to pre-operative and post-operative data respectively. These analyses demonstrated a significant positive correlation between quadriceps strength indices at both testing speeds and the two hop tests pre-operatively (p's < 0.007) and between quadriceps strength indices at both speeds and all five functional tests post-operatively (p's < 0.01). Assessed using Steiger's formula, there was a significant increase in the correlation between quadriceps strength indices and three functional tests post-operatively compared to pre-operatively (p < 0.05). No significant correlation between hamstring strength indices and functional scores existed pre-or post-operatively. This study has shown a significant correlation exists between quadriceps strength indices and functional stability both before and after surgery, this relationship does not reach significance between hamstring strength indices and functional stability.

Athletes with shoulder pathology consistently demonstrate abnormalities in scapular rotator activity, suggesting that muscle dysfunction is a factor to consider in the aetiology or recurrence of shoulder pain. However, one important measure of the coordinated activity between the scapular rotators, their timing or temporal recruitment pattern, remains undetermined. The purposes of this study were to 1. provide normative data on the temporal recruitment pattern of the scapular rotators in freestyle swimmers, 2. determine the effect of a unilateral shoulder injury on this pattern, 3. determine whether these effects extend to the non-injured side, and 4. determine the effect of injury on the consistency (variability) of muscle recruitment. Surface EMG data for the upper and lower trapezius and serratus anterior were recorded bilaterally from two groups of competitive freestyle swimmers during controlled bilateral elevation in the plane of the scapula. An injured group comprising nine swimmers with unilateral shoulder pathology and a control group of nine non-injured swimmers were included. Temporal data determined for the onset of muscle activation for each muscle were then compared between groups using an ANOVA and a one-sided F test. The results of the study indicate that in non-injured swimmers, upper trapezius is activated 217 ms prior to shoulder motion, followed by serratus anterior activation 53 ms after motion commences. Lower trapezius was not recruited until 349 ms after shoulder motion, when the arm had attained 15 degrees elevation. In injured swimmers, all three muscles on the injured side displayed significantly increased variability in the timing of activation (p < 0.05), whilst the serratus anterior was significantly delayed in its activation on the non-injured side (p < 0.05). Skill hand preference was shown to have no effect on muscle recruitment. The findings of this study indicate that a relationship does exist between shoulder injury and the temporal recruitment patterns of the scapular rotators, such that injury reduces the consistency of muscle recruitment. They further suggest that injured subjects have muscle function deficits on their unaffected side.

Six-year outcomes were very satisfactory irrespective of graft source. However, reconstruction using the hamstring tendons resulted in improved functional performance and a lower incidence of osteoarthritis.

Musculoskeletal disorders are considered the underlying cause of cervicogenic headache, but neck pain is commonly associated with migraine and tension-type headaches. This study tested musculoskeletal function in these headache types. From a group of 196 community-based volunteers with headache, 73 had a single headache classifiable as migraine (n = 22), tension-type (n = 33) or cervicogenic headache (n = 18); 57 subjects acted as controls. Range of movement, manual examination of cervical segments, cervical flexor and extensor strength, the cranio-cervical flexion test (CCFT), cross-sectional area of selected extensor muscles at C2 (ultrasound imaging) and cervical kinaesthetic sense were measured by a blinded examiner. In all but one measure (kinaesthetic sense), the cervicogenic headache group were significantly different from the migraine, tension-type headache and control groups (all P < 0.001). A discriminant function analysis revealed that collectively, restricted movement, in association with palpable upper cervical joint dysfunction and impairment in the CCFT, had 100% sensitivity and 94% specificity to identify cervicogenic headache. There was no evidence that the cervical musculoskeletal impairments assessed in this study were present in the migraine and tension-type headache groups. Further research is required to validate the predictive capacity of this pattern of impairment to differentially diagnose cervicogenic headache.