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The time course of skin-plus-fat compression was studied in 18 subjects (6 males and 12 females) using a skinfold caliper—electronic recorder. Replicate measurements were taken on three sites: triceps, abdominal and iliac. Compression comformed to a two-component exponential model. The range of first component half-times for males and females was 0.9 to 1.4 seconds. Second component half-times ranged from 10.0 to 21.4 seconds. The female second-component half-times were 15, 46 and 35% faster than the males for the triceps, abdominal and iliac sites, respectively. Male-female differences in the compression ratio (computed as the ratio of the initial skinfold to the 60 seconds skinfold) were found only at the iliac site. Repeated measures ANOVA revealed no regional differences in female skinfold compressibility while male skinfolds exhibited significantly greater compressibility at the iliac site than either the triceps or abdominal sites. Reliability of skinfold compression ranged from r = 0.61 to r = 0.91. The test-retest reliability was determined on a second sample of 27 subjects at the triceps and iliac skinfolds. Two investigators read the calipers within 4 seconds of application. All reliabilities exceeded r = 0.92. It was concluded that to minimize compression skinfold measurements can be read within 4 seconds of caliper application with no appreciable loss in reliability.