Task complexity and maximal isometric strength gains through motor learning

Abstract

This study compared the effects of a simple versus complex contraction pattern on the acquisition, retention, and transfer of maximal isometric strength gains and reductions in force variability. A control group (N = 12) performed simple isometric contractions of the wrist flexors. An experimental group (N = 12) performed complex proprioceptive neuromuscular facilitation (PNF) contractions consisting of maximal isometric wrist extension immediately reversing force direction to wrist flexion within a single trial. Ten contractions were completed on three consecutive days with a retention and transfer test 2‐weeks later. For the retention test, the groups performed their assigned contraction pattern followed by a transfer test that consisted of the other contraction pattern for a cross‐over design. Both groups exhibited comparable increases in strength (20.2%, P < 0.01) and reductions in mean torque variability (26.2%, P < 0.01), which were retained and transferred. There was a decrease in the coactivation ratio (antagonist/agonist muscle activity) for both groups, which was retained and transferred (35.2%, P < 0.01). The experimental group exhibited a linear decrease in variability of the torque‐ and sEMG‐time curves, indicating transfer to the simple contraction pattern (P < 0.01). The control group underwent a decrease in variability of the torque‐ and sEMG‐time curves from the first day of training to retention, but participants returned to baseline levels during the transfer condition (P < 0.01). However, the difference between torque RMS error versus the variability in torque‐ and sEMG‐time curves suggests the demands of the complex task were transferred, but could not be achieved in a reproducible way.

The cross education of strength and skill following unilateral strength training in the upper and lower limbs

“…However, most studies in this field examine the transfer of strength and skill separately following unique training paradigms (Keogh et al 2010;Ruddy and Carson 2013). Since all resistive exercise (i.e., strength training) includes a skill component, and therefore the potential for motor learning (Green et al 2014;McGuire et al 2014aMcGuire et al , 2014b, it is likely that a strengthtraining program results in the cross education of both strength and skill. Therefore, the present study investigated the presence of skill transfer (cross education of skill) following unilateral strength training.…”

Neuromuscular Adaptations to Short-Term High-Intensity Interval Training in Female Ice-Hockey Players

“…Reduced level of antagonist co-activation in the tibialis anterior muscle during plantarflexion suggested that, the functional improvements were partly due to motor learning. The level of co-activation is typically reduced at the early stages of strength training (18,22). The HIIT may thus have improved selective motor control, but it should be noted that reduction in the co-activation can occur also due to increased reciprocal inhibition at the spinal level (15).…”

“…Four of them dropped out due to personal reasons or illness. The remaining fourteen subjects (height 165 ± 5 cm, weight 67 ± 13 kg, age 22 ± 3, age range [16][17][18][19][20][21][22][23][24][25][26][27][28]1 under aged) participated in all tests and training sessions. The subjects were informed about the risks, requirements and benefits of the study before signing written consent.…”