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L B Cooper

Publications and source records attributed to L B Cooper.

4 recordsLinked to original sources
PubMed1986

Systematic ankle stabilization and the effect on performance.

Stabilization of the ankle joint is used as a deterrent to injury, however, insufficient or excessive ankle control can cause negative effects. This study determined the effects of systematic changes in ankle and subtalar joint stabilization on performance through an obstacle course. Data were collected on six subjects as they completed two test procedures. Ankle range of motion in the sagittal and frontal planes was determined using a modified Inman apparatus. Completion time through an obstacle course, set up on a basketball court, was used as a measure of performance. High-top basketball shoes were constructed with pockets which allowed strips of plastic (stiffeners) to be positioned just anterior and posterior to the medial and lateral malleoli. Four shoe conditions were used including the shoe with no stiffeners. Significant differences (P less than 0.05) in eversion, flexion, and inversion were found between the shoe conditions. A general trend of decreased range of motion with increased restriction was observed. Significant differences (P less than 0.05) in performance were found between the shoe conditions, with a general trend of increased times with increased restriction. These results indicate that systematic changes in the range of motion of the ankle and subtalar joints can measurably affect performance.

Adult↗
PubMed1985

The effect of varied stride rate upon shank deceleration in running.

The purpose of this study was to determine the effects of systematic changes in stride rate and length at a given running speed on the peak shank deceleration (PSD) experienced during ground contact. Data were collected from 10 well-trained subjects as they ran on a treadmill at a pace of 3.8 m s-1 (7-min mile-1). Shank deceleration was measured by a lightweight accelerometer which was tightly attached over the distal medial tibia. High-speed films (200 Hz) were taken from a side view to quantify modifications in sagittal plane movement which might have accompanied the stride rate changes. Five stride rate conditions were randomly presented - 10% slower, 5% slower, normal, 5% faster and 10% faster. Average PSD was computed from 10 steps during each condition and testing was repeated on three different occasions. For each session, PSD observed for each condition was normalized to that observed at the normal stride rate in order to minimize the effects of variations in attachment of the accelerometer between and within subjects. The normalized PSD results at each stride rate tested were - normal = 1.0, 10% slower = 1.09, 5% slower = 1.03, 5% faster = 0.96 and 10% faster = 0.91. Significant differences were found between all these means except normal and 5% slower. The kinematic analysis revealed non-significant results for hip, knee and ankle joint angles at touchdown for the various stride rates. Application of the findings to existing analytical models indicated that, for a given running speed, peak impact forces in the ankle and knee joints decreased as stride rate increased.

Acceleration↗