Jimmy Smith

Oxygen uptake response to stroke rate manipulation in freestyle swimming.

UNLABELLED During gait, humans choose a combination of step length and step rate that minimizes V˙O2. However, little work has been reported on the existence of such optimization in swimming. PURPOSE The purpose of this study was to examine the manipulation of stroke rate on V˙O2 in submaximal, constant speed freestyle swimming. METHODS Preferred stroke rate for swimming freestyle at 1.0 m·s(-1) in a flume was determined for 10 competitive swimmers (mean ± SD: age = 33.3 ± 13.6 yr, height = 175.3 ± 8.6 cm, weight = 74.9 ± 12.2 kg). Participants then completed flume swims at 1.0 m·s(-1) with stroke rates equal to -20%, -10%, 0%, +10%, and +20% of their preferred stroke rate in a randomized order during which V˙O2 was continuously monitored. Each trial continued for 1 min after steady-state V˙O2 was verified (∼4-5 min). During the final minute of each trial, V˙O2 was measured using the Douglas bag technique, HR was recorded, and kick rate (KR) was computed using the time needed to complete 30 kicks. RPE was reported immediately after each trial. RESULTS V˙O2 increased 11%-16% (P < 0.05) when stroke rate was reduced but was nominally affected when stroke rate was increased. Likewise, HR increased 4%-6% (P < 0.05), and RPE increased 15%-30% (P < 0.05) when stroke rate was reduced but not affected when stroke rate was increased. CONCLUSIONS These data suggest that these swimmers preferred to swim freestyle at the lowest stroke rate (or the longest stroke length) that did not require an increase in V˙O2.

Do wrist orthoses cause compensatory elbow and shoulder movements when performing drinking and hammering tasks

Purpose Wrist orthoses are used by occupational therapists to decrease pain, support weak muscles and protect tissues during healing. However, use of wrist orthoses has been observed to produce compensatory movements in other upper extremity joints. This paper aims to determine whether wearing wrist orthoses produced compensatory movements of the elbow in addition to the shoulder when performing drinking and hammering tasks. Design/methodology/approach Two twin-axis electrogoniometers were positioned on the elbow and shoulder to track joint movement. The four conditions were drink with orthosis, hammer with orthosis, drink without orthosis and hammer without orthosis. Joint movement was defined as total angular excursion of the joint throughout the performance of the task. Separate 2 × 2 (joint × orthosis) repeated measures analyzes of variance (ANOVA) were used to evaluate differences in joint excursion of the elbow and shoulder joints between orthosis conditions for each task. Findings Wearing a wrist orthosis did not change the amount of joint excursion compared to not wearing an orthosis during the drinking and hammering tasks. Originality/value Findings suggest that wrist orthoses do not result in statistically significant changes in elbow and shoulder joint movements during simulated drinking and hammering tasks.