Question

Method: Thirty-two horses were randomly selected from a pool of 68 Thoroughbreds in one breeding farm in Kentucky. The subjects ranged from 18 to 61 months old and included 17 males and 15 females. Measurements of shoulder and elbow range of motion were recorded in triplicate. Signalment information collected included sex, weight and age of each horse. The outcome factors for the study were range of shoulder flexion and extension. The theorized exposures, age, sex, weight, racing history and elbow range of motion, were compared against the outcome variables.

Results: Males were significantly heavier and older than females. Mean shoulder flexion was 62.75° and mean shoulder extension 118.50°. The mean shoulder flexion of raced Thoroughbreds was 63.95° compared with 61.65° for unraced horses (mean difference −2.30, 95% confidence interval −4.31 to -0.29). The mean shoulder extension of raced Thoroughbreds was 102.95° compared with 101.65° for unraced horses (mean difference −1.30, 95% confidence interval −4.31 to 1.71).

The following table was created to report additional findings:

Movement	Mean range	Standard deviation	p-value
Shoulder flexion
Left     Right	64.35 62.13	7.10 5.87	0.22
Shoulder extension
Left     Right	120.11 116.09	4.12 3.85	0.04

1. Which of the following statements represent(s) correct interpretation of the study findings on shoulder flexion and extension? More than one answer may be correct.

1. There was a significant difference in flexion between raced horses and unraced horses; but no significant difference in comparing left side to right.
2. There was no significant difference in flexion between raced horses and unraced horses; but there was a significant difference in comparing left side to right.
3. There was a significant difference in extension between raced horses and unraced horses; but no significant difference in comparing left side to right.
4. There was no significant difference in extension between raced horses and unraced horses; but there was a significant difference in comparing left side to right.

Answer 1

There was no significant difference in flexion between raced horses and unraced horses; but there was a significant difference in comparing left side to right.

There was no significant difference in extension between raced horses and unraced horses; but there was a significant difference in comparing left side to right.