The Comparison Of Speed Between The Head-first And Feet-first Slide Technique

Introduction
Baseball sliding is a technique used by players to assist arriving to next base quickly and to prevent an opponent’s tag
[1,2]. An aggressive baseball team must pay a lot of attention to sliding. The sliding technique was classified as headfirst
and feet-first base on the leading body part of the player during sliding [3,4]. For coaching perspective, they need
more evidences to teach players sliding technique and to bring sliding fast and safety. Therefore, the purpose of this
study is to comparison of speed between the head-first and feet-first slide technique.

Methods
Subjects consisted of 15 collegiate players(age: 20.4±1.1 years; body height: 174.8±4.3cm; body weight: 76.9±10.3kg).
We used digital camera (Sony-DCR PC115) that was positioned in the right field between first and second base to
capture the whole sliding course. Each player performed 3 trials each of both head- first and feet-first sliding
techniques. Each sliding complete had 3 minutes interval for rest. The films analysis of base-running time and speed
was used Silicon Coach Software (pro USC-500, 60 film/sec) to calculate. The analysis variables including slide time,
speed, and accelerate speed. Pair-T test was used to compare between head-first and feet-first slide technique by using
SPSS version 8.0(SPSS, Chicago, IL).

Results
There was had significantly difference between head-first and feet-first slide times (P=0.002), speed (P=0.001), and
accelerate speed (P=0.001). The results present in the Table I.

Discussion/Conclusions
The results were showed that feet-first sliding was faster than head-first sliding in sliding time, speed, and accelerate
speed. Our study was not supported the previous studies [5]. The possible reason is the surface area of anterior trunk,
which contacts the ground, by using head-first sliding is greater than the surface area of posterior leg and buttock by
using the feet-first sliding. That resulted greater amount of friction between the ground and the body in the head-first
sliding. It may reduce the player’s speed [3,4].

References
[1] Delmonico R (1992). Hit and Run Baseball. Champaign, IL, Human Kinetics Publishers, Inc.
[2] Johnson M, et al. (2001). Baseball- Skills & Drills. Champaign, IL, Human Kinetics Publishers, Inc.
[3] Kane SM, et al. (2002). Am J Sports Med, 30, 834-836.
[4] Hosey RG, et al. (2003). Clin J Sport Med, 13,242-244.
[5] Corzatt RD. (1984). Am J Sports Med, 12, 229-232.

NOTA: O texto com a iconografia está no anexo.

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