The effects of mild one-legged isometric or dynamic training

Abstract

Four men isometrically trained their stronger leg for 19 weeks (attempted knee extension against a restraining strap incrementally increasing to 30 brief maximal contractions X 6 wk-1). Five others similarly trained dynamically (repeated knee extension against a 63 N resistance force, incrementally increasing to 300 extensions X 6 wk-1). Before, at regular intervals during training and after de-training (between 7-11 weeks) measurements were made using trained and control legs of: Maximum Voluntary Isometric Contraction (M.V.C.), Endurance at 60% M.V.C., Knee Extension Performance Test (K.E.P.T.) and One-legged Work Test. Isometric training produced a 30% (p less than 0.01) increase in M.V.C. with a 15% (p less than 0.05) increase in the control leg. These changes persisted with some deterioration after the de-training period. Endurance at 60% M.V.C. remained unchanged, even though M.V.C. was increasing in both trained and control legs. There was some evidence that isometric training improved the cardio-vascular response to one-legged exercise. Dynamic training did not result in changes in M.V.C., Endurance at 60% M.V.C. or the One-legged work Test, but K.E.P.T. (time taken for 50 knee extensions at a comfortable pace against 63 N resistance) improved by 33% (p less than 0.01) and 28% (p less than 0.01) in the trained and control legs respectively. Isometric training resulted in similar improvements in performance of K.E.P.T. (28%, p less than 0.05, trained leg; 18%, p less than 0.05 control leg). For similar time spent in training, isometric work appeared more effective than dynamic work in improving the parameters of muscle function, these improvements appeared to be both centrally (C.N.S.) and locally mediated.

A Systematic Review and Meta-Analysis on the Longitudinal Effects of Unilateral Knee Extension Exercise on Muscle Strength

“…The overall number of subjects (see section 3.1) are such that one would not expect much impact. Since there is only one study that reported on subjects with daily activity levels higher than those of recreationally active individuals (Parker, 1985) and one study that did not provide any information about this (Jones and Rutherford, 1987), we believe that the activity of the subjects might be comparable. Hence, we believe that the physical condition, i.e., if non-active or athletes perform the same isometric training program (Patrick and Caterisano, 2002), did not influence the outcome of this meta analysis.…”

“…Bonde Petersen (1960) Yes Yes Carolan and Cafarelli (1992) Yes Yes Ema et al (2017) Yes No Garfinkel and Cafarelli (1992) Yes Yes Grimby et al (1973) No No Jones and Rutherford (1987) No Yes Kubiak et al (1987) Yes No Kubo et al (2001) No No Lewis et al (1984) No Yes Lucca and Recchiuti (1983) Yes Yes Mohr et al (1985) Yes No Oliveira et al (2013) Yes No Parker (1985) No Yes Rich and Cafarelli (2000) Yes Yes Rutherford and Jones (1986) No Yes Szeto et al (1989) No Yes Tillin et al (2011) No Yes Weir et al (1994) Yes Yes Weir et al (1995) Yes Yes…”

Table_1.pdf

“…From the included studies, only Parker (1985) report that the daily activity levels of the subjects were higher than those of recreationally active individual. Jones and Rutherford (1987) provided no information on the activity level of the subjects.…”

“…Since nothing was explicitly stated in this study, we considered the subjects as recreationally active individuals. Therefore, only four subjects, the ones in Parker (1985), were considered as recreationally highly active individuals. Total number of trained subjects in the studies included in this review is 307.…”

“…Total number of trained subjects in the studies included in this review is 307. Subjects in Parker (1985) corresponds to 1.3% of the total trained subjects.…”