External Focus enhanced Vertical Jump: Skilled Volleyball Players vs Novices Compared

An external focus is defined as directing one’s attention to objects and the environment. Conversely, an internal focus is defined as directing one’s attention to the movements themselves. According to the constrained action hypothesis, an external focus could enhance sports performance in tasks such as golf putting, basketball free throw, jumping, and sprinting. However, few studies have examined whether the effect of an external focus on jump performance differs between experts and novice participants. This study aimed to clarify whether the influence of an external focus during jump differs between expert volleyball players and novice participants. Forty participants were recruited. We tested expert volleyball players (n = 20, Mage ± SD = 20.2 ± 0.9 years) who were members of a college volleyball club, and novice participants for volleyball (n = 20, Mage ± SD = 20.9 ± 1.1). The Yardstick Jump Testing System (Swift Performance) was used to record maximal vertical jump-and-reach height. Each participant performed three trials under two conditions (internal focus vs external focus). The jump-and-reach height (cm), flight time (ms) and attention score were subjected to a mixed repeated-measures analysis of variance (ANOVA), including the factors of “group” (experts/novice) and “condition” (external focus/internal focus). The average jump-and-reach heights for experts under the external and internal focus conditions were 44.6 cm (SD=5.1) and 42.8 cm (SD=4.9), respectively. For novices, the average heights were 42.5 cm (SD=5.2) and 41.4 cm (SD=4.6), respectively. Jump-and-reach height was significantly higher in the external focus condition than in the internal focus condition (F(1, 38) = 29.66, p = .01, η2p = .44). We did not find a difference in flight time between conditions. An external focus may facilitate effective whole-body movement, i.e., coordination between the upper and lower body during a jump. Overall, the external focus enhanced jump performance compared to the internal focus regardless of sports expertise.