The level of effort, rather than muscle exercise intensity determines strength gain following a six-week training

Abstract

Aim This study investigated the effect of voluntary motor effort during a low-intensity (30% maximal voluntary contraction [MVC]) muscle exercise training program on increasing muscle strength. Materials and Methods Eighteen young and healthy individuals were randomly assigned to one of three groups: high mental effort (HME), low mental effort (LME), or a no-training control (CTRL) group. Training lasted for 6 weeks (15 min/day, 5 days/week). The participants’ right-elbow flexor muscle strength was measured before and after the training program. Key findings After training, the HME group gained 20.47 ± 8.33% (P = 0.01) strength while the LME and CTRL groups had negligible strength changes (1.89 ± 0.96% and −3.27 ± 2.61%, respectively; P > 0.05) despite muscle contraction intensity (30% MVC) sustained during training was the same for the HME and LME groups. These results suggest that the level of effort involved in resistance exercise training plays a critical role in determining the amount of strength augmentation. Significance The finding that high effort combined with low-level physical exercise training can significantly increase muscle strength has rehabilitation applications as many patients and frail older adults have difficulties in participating in high-intensity exercise training such as lifting heavy weights. High effort plus low-level muscle exercise might serve as a safe training regimen for effective muscle strengthening in vulnerable populations.

Elderly may benefit more from motor imagery training in gaining muscle strength than young adults: A systematic review and meta-analysis

“…Table 1 presents details of each included article regarding sample, measures, and key results. The sample size of the MIT groups in the included studies ranged from 6 to 18, three studies with a sample size of 6 ( Leung et al, 2013 ; Yao et al, 2013 ; Jiang et al, 2017 ), two studies with a sample size of 8 ( Ranganathan et al, 2004 ; Bahari et al, 2011 ), two studies with a sample size of 9 ( Lebon et al, 2010 ; Grôspretre et al, 2017 ), nine studies with a sample size of 10 ( Yue and Cole, 1992 ; Sidaway and Trzaska, 2005 ; Fontani et al, 2007 ; Shackel and Standing, 2007 ; Wright and Smith, 2009 ; de Ruiter et al, 2012 ; Darvishi et al, 2013 ; Jiang et al, 2016 ; Bouguetoch et al, 2021 ), three studies with a sample size of 12 ( Cornwall et al, 1991 ; Reiser and Munzert, 2011 ; Goudarzian et al, 2017 ), one study with a sample size of 15 ( Mamone, 2013 ), three studies with a sample size of 16 ( Smith et al, 2003 ; Niazi et al, 2014 ; Alenezi, 2018 ), and one study with a sample size of 18 ( Herbert et al, 1998 ). All the selected studies included a non-exercise and/or a non-imagery control group.…”

The Time Course of Quadriceps Strength Recovery After Total Knee Arthroplasty Is Influenced by Body Mass Index, Sex, and Age of Patients: Systematic Review and Meta-Analysis

“…Thus, combining the two practice methods simultaneously, patients could almost always activate not only the muscle but also the neural circuits controlling the motor action, adding a low-intensity actual movement execution exercise and/or cognitive training to NmES. Accordingly, the most recent studies suggest that cognitive training (i.e., motor imagery) alone ( 104 ), in addition to low-intensity strength training ( 105 ) or NmES ( 106 ), has a beneficial effect on strength increase in both the symptomatic and asymptomatic populations ( 107 , 108 ). Thus, Jiang et al ( 109 ) reported that at the end of a 12-week training of healthy elderly subjected to both high-intensity physical exercise and high mental effort (HME), elbow flexion strength was significantly increased compared to the control group, with no significant difference between the exercise-only and HME groups.…”

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“…Results of a study concluded that level of effort involved in resistance exercise training plays a critical role in determining the amount of strength augmentation. 16 . It is well known that acute or chronic increases in physical activity result in structural, metabolic, hormonal, neural, and molecular adaptations that increase the level of force or power that can be sustained by a muscle.…”