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AIM: To examine the reliability of peak and sustained grip strength in children using the Grippit. We compared the reliability of one trial, the best and mean of three trials and the reliability within 6-, 10- and 14-year-old groups.

DESIGN: Test-retest study.

METHODS: Grip strength with the Grippit instrument was evaluated at two test occasions in 58 children. Intraclass correlation coefficient 2.1 (ICC), standard error of measurement (SEM) also expressed as a percentage value (SEM%), coefficient of repeatability and coefficient of variation were calculated.

RESULTS: The test-retest reliability was good for both peak and sustained grip strength. The mean and best of three trials were equally reliable. Peak grip strength best of three trials, for example, was more reliable for the 6-year-olds (ICC 0.96, SEM% 6.3) and 14-year-olds (ICC 0.96, SEM% 5.2) compared to the 10-year-olds (ICC 0.78, SEM% 12.5). For peak grip strength in the whole sample, there was a systematic bias with better performance at the second measurement.

CONCLUSION: Grip strength assessment in children with Grippit results in good relative and absolute reliability for peak and sustained grip strength. We recommend that three test trials are used. The mean of and the best of three trials are comparable.

In muscle energy technique (MET), palpation is an important tool aimed at detecting asymmetry and selecting interventions. The aim of this study was to test the inter-examiner reliability of static palpation of the transverse processes of L5 (L5), sacral sulci (SS), inferior lateral angles of the sacrum (ILA), and the medial malleoli (MM) in a clinical setting. Twenty-five participants, aged 18–78 years, with low back pain and/or sacroiliac pain with or without radiating pain to the knee, were independently examined by two experienced physiotherapists. For L5, SS, ILA, the proportion of observed agreement was 40–44% and the κ coefficient 0.11 (SE=0.12) to 0.17 (SE=0.10). For MM, the observed agreement was 52% and the κ coefficient 0.28 (SE=0.15). Differences in palpation technique seem to be the most likely source of the low inter-examiner reliability in this study. For clinical practise, continued use of these tests as methods for detecting asymmetry and selecting interventions is of doubtful utility.

To compare training programs for women with trapezius myalgia regarding physical performance and pain, 102 women were randomized to strength, endurance, co-ordination and non-training groups. Before and after the intervention, static strength and dynamic muscular endurance in shoulder muscles were measured on a Cybex II dynamometer. Muscle activity in shoulder muscles was monitored via surface EMG. The signal amplitude ratio between the active and passive phase of repeated contractions indicated the ability to relax. Pain at present, pain in general and pain at worst were measured on visual analogue scales. After training, within group comparisons showed that the training groups rated less pain, and in the strength training group ratings of pain at worst differed from the non-training group. Using the non-training group as a reference, static strength increased in the strength and endurance training groups and muscular endurance in all training groups. The study indicates that regular exercises with strength, endurance or co-ordination training of neck/shoulder muscles might alleviate pain for women with work-related trapezius myalgia.

The aim of this study was to examine the effects of training on the structural characteristics of the trapezius muscle in women with work-related trapezius myalgia. Muscle biopsies were taken before and after 10 weeks of three different training programs (strength, endurance and coordination). Enzyme-immunohistochemical analysis was performed to assess muscle fibre types, fibre area, capillary supply and cytochrome c oxidase (COX) activity. There was an increase in the proportion of type IIA fibres in strength trained group (P < 0.05). Strength training elicited a preferential increase in the area of type II fibres (P < 0.05); both strength and endurance programs induced an increase in the number of capillaries around type I and IIA muscle fibres. Finally, all training programs induced a decrease in the proportion of COX-negative fibres. In conclusion, the trapezius muscle of women with neck and shoulder myalgia is characterised by a great potential of adaptation to physical exercise over a period of 10 weeks. The significant changes in the number of capillaries and the specific changes induced by training at the level of muscle fibres might well explain the improvement of muscle function.