Feedback controlled force enhancement and activation reduction of voluntarily activated quadriceps femoris during sub-maximal muscle action

Does weightlifting increase residual force enhancement?

“…In the stretch-contraction, the dynamometer footrest was moved linearly from L 110 to L 90 with a velocity of 30 cm/s. Depending on the individual leg length proportions of the subjects, this movement leads to a mean knee angular velocity of 52°/s711°/s, which is slightly lower than 60°/s used by Hahn et al (2010) and Seiberl et al (2012). Subject specific differences in angular velocity are expected to have no influence on RFE because RFE is independent of stretch velocity (Edman et al, 1978;Siebert et al, 2015).…”

“…The relevance of RFE for stretch-shortening cycles of the human M. adductor pollicis was recently reported (Seiberl et al, 2015b) and RFE might be relevant in storing and releasing energy during squats, too. Furthermore, submaximal eccentric contractions might be sufficient to trigger RFE mechanisms, since RFE was observed for submaximal eccentric contractions (Pinniger and Cresswell, 2007;Seiberl et al, 2012). Therefore, we hypothesize that weightlifters exhibit RFE, and that the amount of RFE is higher than that of a reference group.…”

“…RFE has been detected at the myofibrillar level (Joumaa et al, 2008), in muscle fiber (Edman et al, 1982;Edman and Tsuchiya, 1996), in muscle (Abbott and Aubert, 1952;Siebert et al, 2015), and for multi-joint movements (Hahn et al, 2010). Furthermore, RFE has been observed during maximal (Hahn et al, 2010) and submaximal (Pinniger and Cresswell, 2007;Seiberl et al, 2012) muscle activation.…”

Residual force enhancement in humans: Current evidence and unresolved issues

“…In the course of these investigations RFE was confirmed for ankle plantar and dorsi flexors (Pinniger and Cresswell, 2007;Power et al, 2012c;Tilp et al, 2009Tilp et al, , 2011, knee extensors (Altenburg et al, 2008;Hahn et al, 2007;Power et al, 2013c;Seiberl et al, 2012Seiberl et al, , 2010Shim and Garner, 2012), and knee flexors (Shim and Garner, 2012). Except for observations presented by Hahn et al (2007), RFE of 4-15% above isometric reference was constantly reported (Table 1).…”

“…Accordingly, for force-controlled active lengthening contractions at 30% maximum voluntary contraction (MVC) Oskouei and Herzog (2005) reported an activation reduction, AR, of 18% in m. adductor pollicis. In terms of relevance of RFE for human locomotion Altenburg et al (2008) and Seiberl et al (2012) tried to reproduce the finding of AR for submaximal contractions of m. quadriceps femoris. Although both found significant AR of 6-9% following active lengthening compared to the purely isometric reference contractions, this was only true for parts of m. quadriceps femoris (Altenburg et al, 2008) or when using a compensation model based on physiological cross-sectional area and individual EMG-torque relations to account for the complexity of m. quadriceps femoris (Seiberl et al, 2012).…”