Author(s): NIE, R., KONG, J., Institution: BEIJING SPORT UNIVERSITY, Country: CHINA, Abstract-ID: 1728

INTRODUCTION:
Internal focus (IF) and external focus (EF) influences motor performance through distinct cognitive mechanisms. While EF generally enhances movement efficiency, IF can disrupt performance but may optimize muscle activation in certain contexts. Eccentric flywheel training, known for its high mechanical tension and neuromuscular adaptations, is widely used to enhance athletic performance. However, no study has explored how attentional focus strategies modulate biomechanical and neuromuscular responses during eccentric flywheel exercises. This study addresses this gap by examining the effects of IF and EF on ground reaction force and muscle activation during eccentric flywheel squats, providing new insights into optimizing performance and rehabilitation.
METHODS:
28 healthy males (aged 18–25) with over 1 year of resistance training experience participated in this randomized, counterbalanced crossover study. 3 AF conditions were tested during eccentric flywheel squats: EF, IF and Control (CO). Ground reaction force (GRF) and surface electromyography (sEMG) of 7 lower limb muscles were measured. GRF peak and mean values were recorded for eccentric and concentric phases, while sEMG signals were normalized to maximal voluntary contractions. Repeated measures ANOVA or Friedman tests were used for statistical analysis, with significance set at p < 0.05.
RESULTS:
Average and peak amplitudes (A.A. and P.A.) of the gluteus maximus, rectus femoris, biceps femoris, semitendinosus, medial gastrocnemius, lateral gastrocnemius, and tibialis anterior were analyzed across conditions. EF resulted in the highest mean (M.) and peak (P.) concentric (C.) and M. eccentric (E.) forces (M.C.=107.65[102.13,115.64];M.E.=87.84[79.58,96.85]; P.C.=128.81[112.26,137.06]; P.E.=103.91[90.33,116.50]), followed by IF(M.C.=90.18[79.45,94.92];M.E.=78.66[70.36,84.11]; P.C.=106.53[94.00,112.14];P.E.=96.38[84.50,101.13]) and CO (M.C.=96.07[75.70,110.82]; M.E.=87.10[75.00,99.80];P.C.=111.06[87.05,112.57]; P.E.=106.93[90.75,120.02],p<0.001,p<0.001,p<0.001,p=0.008). EF also showed superior muscle activation efficiency, particularly in the gluteus maximus (PA.A.<0.001, PP.A.=0.002) and biceps femoris (PA.A.=0.01, PP.A.=0.025). In contrast, IF enhanced rectus femoris (PA.A.=0.019, PP.A.=0.36) and semitendinosus PA.A.=,0.004, PP.A.<0.001) activation compared to CO. These findings suggest EF optimizes force production and movement efficiency during eccentric flywheel squats.
CONCLUSION:
EF enhances force production and movement efficiency during eccentric flywheel squats compared to IF and CO. IF demonstrates benefits for specific muscle activations, such as the rectus femoris and semitendinosus. These findings suggest that EF is more effective for optimizing overall performance, while IF may be useful for targeted muscle engagement. Integrating attentional focus strategies with eccentric flywheel training could enhance athletic performance and rehabilitation outcomes.