Moment-angle Relations after Specific Exercise

Abstract

This study examined the amount and time-course of shifts in the moment-knee angle relation of the quadriceps (QF) and hamstring (HAM) muscles in response to different length-restricted strength training regimens. Thirty-two athletes were divided into three different training groups (G1-3): G1 performed isometric training at knee joint angles corresponding to long muscle-tendon unit (MTU) length for QF and HAM; G2 conducted concentric-eccentric contraction cycles that were restricted to a knee joint range of motion corresponding to predominantly long MTU length for QF and HAM; G3 combined the protocols of G1 and G2. Moment-knee angle and EMG-knee angle relations of QF and HAM were measured on five different occasions: two times before, after five and eight weeks of training and four weeks post training. Moments and EMG-data of each subject were normalized to the largest value produced at any knee joint position [% Max.]. Obtained by curve fitting, the optimal knee joint angle for QF moment production was significantly (P<0.05) shifted to longer MTU length in G1 and G3 after 5 weeks of training and in G2 after 8 weeks of training. Contrary, no significant shifts were detected for HAM. Our data suggest that the predominant MTU length during loading is a major trigger for human force-length adaptations.

Effects of isometric training on the knee extensor moment–angle relationship and vastus lateralis muscle architecture

“…The changes in the EMG activity did not appear to be a key factor in the strength increases observed in the group that trained at long muscle lengths, given that, similar to other studies (Blazevich et al 2009;Ullrich et al 2009;Noorkoiv et al 2014), we did not find any significant shift or increases in the agonist EMG amplitude. However, the group that trained at short muscle lengths showed significant increases in the EMG RMS of the KEs measured during the isokinetic test (Fig.…”

“…Isometric resistance training can be an effective alternative to dynamic training, because of its lower risk-benefit ratio (Burgess et al 2007) and the limited equipment that requires. Therefore, it is not surprising that this contraction mode is utilized in rehabilitation and physical therapy contexts and even in sports performance (Ullrich et al 2009). For example, specific angle isometric strength training programs can be applied in clinical populations where pain or impairments in some parts of the ROM are present.…”

“…2010b; McMahon et al 2013) and isometric (Kubo et al 2006;Ullrich et al 2009;Noorkoiv et al 2014) resistance training. This relationship can be assessed in vivo by analysing the moment-angle relationship of isokinetic or isometric tests performed at different joint angles (Brockett et al 2004;Brughelli and Cronin 2007;Ullrich et al 2009).…”

“…This relationship can be assessed in vivo by analysing the moment-angle relationship of isokinetic or isometric tests performed at different joint angles (Brockett et al 2004;Brughelli and Cronin 2007;Ullrich et al 2009). Shifts in the moment-angle relationship towards longer muscle lengths have been related to lower injury risk in the knee flexor and extensor muscles, because the sarcomeres of the muscle are operating near the plateau of their lengthtension curves during a greater part of the joint range of motion (ROM) (Brockett et al 2004;Brughelli and Cronin 2007).…”

Long-term data of gait characteristics and moment–knee angle relations in female total knee arthroplasty patients

“…It is accepted that QF and HAM force generation is needed for daily activities such as walking uphill and downhill, cycling and climbing stairs and to maintain knee joint stability (Judd et al, 2012;Stevens-Lapsley et al, 2010a;Ullrich et al, 2009;Wank et al, 1998). However, no work studied gait patterns and the moment-knee angle relations of QF and HAM in the long-term after TKA.…”