Ipsilateral Lower-to-Upper Limb Cross-Transfer Effect on Muscle Strength, Mechanical Power, and Lean Tissue Mass after Accentuated Eccentric Loading

Abstract

Background and Objectives: To investigate the effects of unilateral accentuated eccentric loading (AEL) on changes in lean mass and function of leg trained (TL) and ipsilateral non-trained arm (NTA) in young men and women. Materials and Methods: In a prospective trial, 69 Physically active university students (20.2 ± 2.2 years) were randomly placed into a training group (n = 46; 27 men, 19 women) or a control group without training (n = 23; 13 men, 10 women). Participants in the training group performed unilateral AEL in the leg press exercise of the dominant leg twice a week for 10 weeks. An electric motor device-generated isotonic resistance at different intensities for both concentric (30% of 1-RM) and eccentric contractions (105% of 1-RM). Changes in thigh and arm lean tissue mass, unilateral leg press and unilateral elbow flexion maximal concentric (1-RM) and isometric strength (MVIC), and unilateral muscle power at 40, 60, and 80% 1-RM for both leg press and elbow flexion exercises before and after intervention were compared between groups, between sexes and between TL and NTA. Results: Both men and women in the training group showed increases (p < 0.05) in lean tissue mass, 1-RM, MVIC, and muscle power for TL. In NTA, 1-RM, MVIC, and muscle power increased without significant differences between sexes, but neither in men nor women changes in lean tissue mass were observed. In addition, men showed greater changes in TL, but changes in NTA were similar between sexes. No gains in any variable were found for the control group. Conclusions: AEL protocol produced similar neuromuscular changes in TL and ipsilateral NTA, which suggests that strong ipsilateral lower-to-upper limb cross-transfer effects were induced by the eccentric-overload training. However, early ipsilateral increases in muscle force and power were not associated with lean mass gains. Both men and women experienced similar changes in NTA; however, men showed greater changes in TL.

Ipsilateral transfer of motor skill from lower to upper limb in healthy adults: A randomized controlled trial

“…Our finding that, in the posttest, the response time of RM sequences of the LL was significantly faster in the LL group as compared to both the SO and NO groups is in line with our hypothesis that LL practice would improve UL performance compared to merely observing the same sequences of the light switches or observing nature films. This finding regarding the ipsilateral transfer of performance from LL to UL supports the findings of the few previous studies that investigated ipsilateral transfer of strength from the LL to the UL in healthy adults and youth [ 26 , 27 , 28 ], and the ipsilateral transfer of a motor skill (2D virtual “moving snake” task and star-line drawing task [ 29 ]) between proximal and distal effectors within the UL [ 18 , 29 ].…”

“…In contrast to the evidence concerning the intermanual transfer of the UL [ 13 – 22 ], very few studies have investigated ipsilateral transfer within the same UL (intramanual transfer) [ 18 , 25 ] and between limbs [ 26 – 28 ]. For example, transfer of a motor skill, in which the participants had to track the head of a snake (2D virtual “moving snake” task), has been found from the shoulder to the finger [ 18 ].…”

“…After shoulder training, the accuracy index (the mean spatial error) of the finger improved. In a study of ipsilateral transfer from the LL to the UL, an increase in the 1 repetition maximum of the ipsilateral biceps brachi was found following a ten-week leg press resistance training program of the LL [ 26 ]. The increase of UL strength was greater after the training of the UL biceps muscle, which was immediately followed by leg press, as compared to training of only the UL biceps [ 28 ].…”

“…Whereas the abovementioned studies describe training that triggered the intermanual transfer of strength and motor skills [ 13 – 24 ] and the ipsilateral transfer of strength from the LL to the UL [ 26 – 28 ], to the best of our knowledge, no current data exists regarding the ipsilateral transfer of motor skills from the LL to the UL and vice versa. This study is the first attempt to determine whether there is an ipsilateral transfer of a motor skill from the LL to the UL, which can potentially provide additional insights about transfer principles and possible clinical applications.…”

Children with Low Handgrip Strength: A Narrative Review of Possible Exercise Strategies to Improve Its Development

“…Similarly, despite a significant change in aerobic capacity after a 12-week concurrent training (moderate-intensity treadmill running training combined with resistance training (MICT + RT) or high-intensity treadmill interval training combined with resistance training (HIIT + RT)) intervention, handgrip strength did not change in the intervention (pre-post change; MICT + RT = −1.1 kg and HIIT + RT = 0.9 kg) and control (pre-post change: −1.3 kg) groups [ 40 ]. Previous studies reported increased muscle strength of the untrained upper extremities due to resistance training of the lower extremities (called the cross-education or cross-transfer effect) [ 41 , 42 ]. However, there are no studies of increased handgrip strength with the above lower-body training intervention.…”