Reliability in novel field-based fitness measurements and post-exercise scores from a physical fitness test battery in older adults.

INTRODUCTION: Physical fitness is strongly associated with daily physical function, health, and longevity in older adults. Field-based tests may provide a reasonable alternative compared to advanced laboratory testing. Separating post-exercise test-scores from reactivity measurements requires sufficient test-retest reliability. Post-exercise test-scores with reliability-analyses of field-based fitness-tests in older adults are lacking. The present study aimed to examine the test-retest-reliability of some novel easily accommodated fitness-test-measurements and compare pre-test scores with post-exercise results in these tests along with other field-based fitness tests in older adults. METHODS: Totally 1,407 community-dwelling-older-adults (69%-female), x̄=71.5±5.0 (65-84 years), performed twelve field-based-fitness-tests at pre-test-1, pre-test-2 and a post-test after an 8-week-exercise-period (twice weekly 1 hour of combined strength and aerobic training). T-tests, intra-class correlation, limits of agreement, standard error of measurement and coefficient of variance were performed between pre-1-and-pre-2-tests, and Repeated-Measures-ANOVA and partial eta squared effect size for post-exercise differences, for men and women in five-year age groups ranging from 65 to 84 years. RESULTS: Between pre-1 and pre-2-tests a significant difference was noted in some of the novel fitness-test-measurements, but generally not e.g., in isometric trunk-flexion and step-up-height on either leg among all sex and age groups. In most of these novel fitness-test-measurements, no significant differences occurred between the two pre-tests. Examples of results from the pre-2-test to the post-test were: isometric-trunk-flexion-45°-endurance and isometric-trunk-extension-endurance improved significantly for both sexes in age groups 65-74 years. Women, but not men, improved the maximal step-up-height for both legs in most age-groups. The speed in the 50 sit-to-stand improved significantly for most age-groups in both sexes. Six-min-walk-distance improved significantly for most age-groups in women but among men only in 65-69 years. In the timed-up-and-go-test, significant improvements were seen for all age-groups in women and in men 70-79 years. No post-exercise improvements were generally observed for grip-strength or balance. CONCLUSIONS: In most of the novel fitness-test measures no significant difference was noted between the two pre-tests in the assessed sex and age groups. Results after the-8-week-exercise-period varied between sex and age-groups, with significant improvements in several of the twelve studied fitness-tests. These findings may be valuable for future projects utilizing easily accommodated physical fitness tests in older adults.

Effect of footwear on intramuscular EMG activity of plantar flexor muscles in walking.

One of the purposes of footwear is to assist locomotion, but some footwear types seem to restrict natural foot motion, which may affect the contribution of ankle plantar flexor muscles to propulsion. This study examined the effects of different footwear conditions on the activity of ankle plantar flexors during walking. Ten healthy habitually shod individuals walked overground in shoes, barefoot and in flip-flops while fine-wire electromyography (EMG) activity was recorded from flexor hallucis longus (FHL), soleus (SOL), and medial and lateral gastrocnemius (MG and LG) muscles. EMG signals were peak-normalised and analysed in the stance phase using Statistical Parametric Mapping (SPM). We found highly individual EMG patterns. Although walking with shoes required higher muscle activity for propulsion than walking barefoot or with flip-flops in most participants, this did not result in statistically significant differences in EMG amplitude between footwear conditions in any muscle (p > 0.05). Time to peak activity showed the lowest coefficient of variation in shod walking (3.5, 7.0, 8.0 and 3.4 for FHL, SOL, MG and LG, respectively). Future studies should clarify the sources and consequences of individual EMG responses to different footwear.

Effect of increasing workload on knee extensor and flexor muscular activity during cycling as measured with intramuscular electromyography.

The purpose of this study was to describe the effect of increasing workload on individual thigh muscle activation during a 20 minute incremental cycling test. Intramuscular electromyographic signals were recorded from the knee extensors rectus femoris, vastus lateralis, vastus medialis and vastus intermedius and the knee flexors semimembranosus, semitendinosus, and the short and long heads of the biceps femoris during increasing workloads. Mean activation levels were compared over the whole pedaling cycle and the crank angles at which onset and offset of activation and peak activity occurred were identified for each muscle. These data were compared between three workloads. EMG activation level significantly increased (p<0.05) with increasing workload in the rectus femoris, vastus medialis, vastus lateralis, vastus intermedius, biceps femoris long head, semitendinosus and semimembranosus but not in the biceps femoris short head. A significant change in activation timing was found for the rectus femoris, vastus lateralis, vastus medialis and semitendinosus. Of the knee flexors only the short head of the biceps femoris had its peak activity during the upstroke phase at the two highest workloads indicating a unique contribution to knee flexion.