Several
studies have already reported that specific foot/ankle muscle reinforcement
strategies induced strength and joint position sense performance enhancement.
Nevertheless the effects of such protocols on sprint performance and plantar
loading distribution have not been addressed yet. The objective of the study
is to investigate the influence of a 5-wk foot/ankle strength training program
on plantar loading characteristics during sprinting in adolescent males.
Sixteen adolescent male athletes of a national training academy were randomly
assigned to either a combined foot/ankle electromyostimulation and resistance
training (FAST) or a control (C) group. FAST consisted of foot medial arch
and extrinsic ankle muscles reinforcement exercises, whereas C maintained
their usual training routine. Before and after training, in-shoe loading
patterns were measured during 30-m running sprints using pressure sensitive
insoles (right foot) and divided into nine regions for analysis. Although
sprint times remained unchanged in both groups from pre- to post- training
(3.90 ± 0.32 vs. 3.98 ± 0.46 s in FAST and 3.83 ± 0.42 vs. 3.81 ± 0.44 s
in C), changes in force and pressure appeared from heel to forefoot between
FAST and C. In FAST, mean pressure and force increased in the lateral heel
area from pre- to post- training (67.1 ± 44.1 vs. 82.9 ± 28.6 kPa [p = 0.06];
25.5 ± 17.8 vs. 34.1 ± 14.3 N [p = 0.05]) and did not change in the medial
forefoot (151.0 ± 23.2 vs. 146.1 ± 30.0 kPa; 142.1 ± 29.4 vs. 136.0 ± 33.8;
NS). Mean area increased in FAST under the lateral heel from pre- to post-
(4.5 ± 1.3 vs. 5.7 ± 1.6 cm2 [p < 0.05]) and remained unchanged in C
(5.5 ± 2.8 vs. 5.0 ± 3.0 cm2). FAST program induced significant promising
lateral and unwanted posterior transfer of the plantar loads without affecting
significantly sprinting performance.
Key words: Track and field, medial arch, reinforcement, injury prevention.
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