Anders Lundervold

• Lundervold, Anders; Ellison, Matthew; Madsen, Klavs; Werkhausen, Amelie & Rice, Hannah (2024). Altered trunk-pelvis kinematics during load carriage with a compliant versus a rigid system. Ergonomics. ISSN 0014-0139. doi: 10.1080/00140139.2024.2390125. Full text in Research Archive Show summary

  Load carriage is a key component of hiking and military activity. The design of the load carriage system (LCS) could influence performance and injury risk. This study aimed to compare a traditional and a compliant LCS during walking and a step-up task to quantify differences in oxygen consumption and trunk-pelvis kinematics. Fourteen participants completed the tasks whilst carrying 16 kg in a rigid and a compliant LCS. There were no differences in oxygen consumption between conditions during either task (p > 0.05). There was significantly greater trunk-pelvis axial rotation (p = 0.041) and lateral flexion (p = 0.001) range of motion when carrying the compliant LCS during walking, and significantly greater trunk-pelvis lateral flexion range of motion during the step-up task (p = 0.003). Carrying 16 kg in a compliant load carriage system results in greater lateral flexion range of motion than a traditional, rigid system, without influencing oxygen uptake.

• Werkhausen, Amelie; Lundervold, Anders & Gløersen, Øyvind (2023). Muscle function during cross-country skiing at different speed and incline conditions. Journal of Experimental Biology. ISSN 0022-0949. 226(12), p. 1–8. doi: 10.1242/jeb.245474. Full text in Research Archive Show summary

  The human musculoskeletal system is well adapted to use energy-efficient muscle–tendon mechanics during walking and running, but muscle behaviour during on-snow locomotion is unknown. Here, we examined muscle and muscle–tendon unit behaviour during diagonal-style cross-country roller skiing at three speed and incline conditions to examine whether skiers can exploit energy-saving mechanisms of the muscle–tendon unit. We assessed lower leg muscle and muscle–tendon unit mechanics and muscle activity in 13 high-level skiers during treadmill roller skiing using synchronised ultrasound, motion capture, electromyography and ski-binding force measurements. Participants skied using diagonal style at 2.5 and 3.5 m s−1 up 5 deg, and at 2.5 m s−1 up 10 deg. We found an uncoupling of muscle and joint behaviour during most parts of the propulsive kick phase in all conditions (P<0.01). Gastrocnemius muscle fascicles actively shortened ∼0.9 cm during the kick phase, while the muscle–tendon unit went through a stretch–shortening cycle. Peak muscle–tendon unit shortening velocity was 5 times faster than fascicle velocity (37.5 versus 7.4 cm s−1, P<0.01). Steeper incline skiing was achieved by greater muscle activity (24%, P=0.04) and slower fascicle shortening velocity (3.4 versus 4.5 cm s−1, P<0.01). Faster speed was achieved by greater peak muscle activity (23%, P<0.01) and no change in fascicle shortening velocity. Our data show that, during diagonal-style cross-county skiing, muscle behaviour is uncoupled from the joint movement, which enables beneficial contractile conditions and energy utilisation with different slopes and speeds. Active preloading at the end of the glide phase may facilitate these mechanisms.

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