Triceps surae muscle-tendon properties in older endurance- and sprint-trained athletes

Abstract

Previous studies have shown that aging is associated with alterations in muscle architecture and tendon properties (Morse CI, Thom JM, Birch KM, Narici MV. Acta Physiol Scand 183: 291-298, 2005; Narici MV, Maganaris CN, Reeves ND, Capodaglio P. J Appl Physiol 95: 2229-2234, 2003; Stenroth L, Peltonen J, Cronin NJ, Sipila S, Finni T. J Appl Physiol 113: 1537-1544, 2012). However, the possible influence of different types of regular exercise loading on muscle architecture and tendon properties in older adults is poorly understood. To address this, triceps surae muscle-tendon properties were examined in older male endurance (OE, n = 10, age = 74.0 ± 2.8 yr) and sprint runners (OS, n = 10, age = 74.4 ± 2.8 yr), with an average of 42 yr of regular training experience, and compared with age-matched [older control (OC), n = 33, age = 74.8 ± 3.6 yr] and young untrained controls (YC, n = 18, age = 23.7 ± 2.0 yr). Compared with YC, Achilles tendon cross-sectional area (CSA) was 22% (P = 0.022), 45% (P = 0.001), and 71% (P < 0.001) larger in OC, OE, and OS, respectively. Among older groups, OS had significantly larger tendon CSA compared with OC (P = 0.033). No significant between-group differences were observed in Achilles tendon stiffness. In older groups, Young's modulus was 31-44%, and maximal tendon stress 44-55% lower, than in YC (P ≤ 0.001). OE showed shorter soleus fascicle length than both OC (P < 0.05) and YC (P < 0.05). These data suggest that long-term running does not counteract the previously reported age-related increase in tendon CSA, but, instead, may have an additive effect. The greatest Achilles tendon CSA was observed in OS followed by OE and OC, suggesting that adaptation to running exercise is loading intensity dependent. Achilles tendon stiffness was maintained in older groups, even though all older groups displayed larger tendon CSA and lower tendon Young's modulus. Shorter soleus muscle fascicles in OE runners may be an adaptation to life-long endurance running.

Peer Review #2 of "Three-dimensional architecture of the whole human soleus muscle in vivo (v0.1)"

“…Fascicle lengths and pennation angles fall within the range previously reported on cadaver muscles (Agur et al, 2003, Ward et al, 2009, Spoor et al, 1991 and in vivo using ultrasound (Stenroth et al, 2016, Kawakami et al, 1998, Maganaris, 2001, Maganaris et al, 1998. Although fascicle lengths between compartments were similar, there was considerable variation in average fascicle lengths between subjects, ranging from 29 to 51 mm at the short muscle length and 37 to 61 mm at the long length.…”

Muscle and tendon tissue properties of competitive soccer goalkeepers and midfielders

“…In their study, it was found that the sprinters also had significantly higher MVC torque values (154.6 Nm) than the endurance athletes (126.3 Nm). Stenroth et al (2015) found a tendency for higher MVC torque in older sprinters (153 Nm) compared to older endurance athletes (age of both groups around 74 years; 116 Nm). In the present study, both the goalkeepers (156.6 Nm)and the midfielders (160.6 Nm) had similar torque values to the sprinters in the study of Arampatzis et al (2007).…”

“…Regarding further parameters of the MTU, Arampatzis et al (2007), in a study of active track and field athletes, but not Stenroth et al (2015), in a study of older athletes, found stiffer tendons in the sprinter group than in the endurance and non-active groups. Due to the explosive characteristic of goalkeeper movements (similar to the sprinters in the study of Arampatzis et al (2007)), we expected that goalkeepers would have stiffer tendons and/or muscles than midfielders and the controls.…”

“…This is in contrast to some results from the literature which showed that training and other chronic processes led to specific adaptations of the MTU. Several studies found structural adaptations due to endurance training habits in the muscle cross sectional area (Stenroth et al, 2015), fascicle length (Oda et al, 2015), tendon length , and tendon stiffness Kunimasa et al, 2015). Moreover, Reeves, Narici, and Maganaris (2003)determined that repeated strength training increased patella tendon stiffness.…”

“…In a study of track and field athletics, Arampatzis, Karamanidis, Morey-Klapsing, De Monte, and Stafilidis (2007) compared endurance athletes with sprinters and found that the sprinters had significantly higher maximum voluntary contraction (MVC) torques and (active) tendon stiffness than the endurance athletes. Additionally, specific adaptations of the MTU have also been reported in endurance athletes: Several studies found structural adaptations due to endurance training habits in the muscle cross sectional area (Stenroth et al, 2015), fascicle length , tendon length , and tendon stiffness Kunimasa et al, 2015).…”