Effects of smiling or crying facial expressions on grip strength, measured with a hand dynamometer and the Bi-Digital O-Ring Test

The effects of smiling or crying facial expressions on grip strength and the Bi-Digital O-Ring Test were evaluated in this study. Ten right-handed basketball players (age group 18-28) were included in the study. Grip strength was measured with a Riester hand dynamometer and the Bi-Digital O-Ring Test successively, after the players had looked at the drawing of a 'crying face' for 5 seconds from a distance of 40 cm at the eye level. Immediately afterwards they were shown the drawing of a 'smiling face' and were asked to grip with the same condition. Once all 10 players carried out this experiment, the order in which the drawings were shown was reversed. We then proceeded to measure the same variables, using the Bi-Digital O-Ring Test. The statistics obtained thereby were subjected to Pearsons correlation coefficient and paired t-test. Using a hand dynamometer and the Bi-Digital O-Ring Test, it was found that, in both tests, the 'smiling face' drawing (first crying, then smiling face: with hand dynamometer, it increased from 8.34 ± 0.97 kg to 9.18 ± 0.9 kg; t = 5.39, p = 0.0001) increased the grip strength of the basketball players, and the 'crying face' drawing (first smiling face, then crying face: with hand dynamometer it decreased from 9.35 ± 0.90 kg to 8.51 ± 0.96 kg; t = 9.81, p = 0.0001) decreased the grip strength. Exposure to the smiling face drawing increased the grip strength, and exposure to the crying face decreased it, in every subject tested in this group. Similar effects were observed with the Bi-Digital O-Ring Test (first crying, then smiling: it increased from -2.80 ± 1.13 to 2.20 ± 1.32; t = 33.54, p = 0.0001; first smiling then crying: it decreased from 2.40 ± 1.34 to -2.20 ± 1.62; t = 15.06, p = 0.0001).