Strength Training Biases Goal-Directed Aiming
Medicine & Science in Sports & Exercise. 2016-09-01; 48(9): 1835-1846
DOI: 10.1249/MSS.0000000000000956
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1. Med Sci Sports Exerc. 2016 Sep;48(9):1835-46. doi: 10.1249/MSS.0000000000000956.
Strength Training Biases Goal-Directed Aiming.
Selvanayagam VS(1), Riek S, DE Rugy A, Carroll TJ.
Author information:
(1)1Sports Centre, University of Malaya, Kuala Lumpur, MALAYSIA; 2Centre for
Sensorimotor Performance, School of Human Movement Studies, The University of
Queensland, Brisbane, Queensland, AUSTRALIA; and 3Institut de Neurosciences
Cognitives et Intégratives d’Aquitaine, CNRS UMR 5287, Université de Bordeaux,
FRANCE.
PURPOSE: Goal-directed movements tend to resemble the characteristics of
previously executed actions. Here we investigated whether a single bout of
strength training, which typically involves stereotyped actions requiring strong
neural drive, can bias subsequent aiming behavior toward the direction of trained
forces.
METHODS: In experiment 1 (n = 10), we tested the direction of force exerted in an
isometric aiming task before and after 40 repetitions of 2-s maximal-force
ballistic contractions toward a single directional target. In experiment 2 (n =
12), each participant completed three training conditions in a counterbalanced
crossover design. In two conditions, both the aiming task and the training were
conducted in the same (neutral) forearm posture. In one of these conditions, the
training involved weak forces to determine whether the level of neural drive
during training influences the degree of bias. In the third condition, high-force
training contractions were performed in a 90° pronated forearm posture, whereas
the low-force aiming task was performed in a neutral forearm posture. This
dissociated the extrinsic training direction from the pulling direction of the
trained muscles during the aiming task.
RESULTS: In experiment 1, we found that aiming direction was biased toward the
training direction across a large area of the work space (approximately ±135°;
tested for 16 targets spaced 22.5° apart), whereas in experiment 2, we found
systematic bias in aiming toward the training direction defined in extrinsic
space, but only immediately after high-force contractions.
CONCLUSION: Our findings suggest that bias effects of training involving strong
neural drive generalize broadly to untrained movement directions and are
expressed according to extrinsic rather than muscle-based coordinates.
DOI: 10.1249/MSS.0000000000000956
PMID: 27116648 [Indexed for MEDLINE]