Ergonomic Strategies Related To Health and Efficiency in Mountain Biking

Abstract

EditorialCycling is a popular recreational and competitive sport with many physical and cardiovascular benefits. While many turn to cycling for its rehabilitative potential in comparison to impact sports such as running, the rate of injury in cycling is still rather high [1] and especially so in mountain biking (MTB) [2][3][4][5][6]. While traumatic injuries often receive the most attention, instances of overuse injuries are of particular concern in mountain biking as symptoms can often go unnoticed [2,3,5].In this respect MTB participants are subjected to vibrations from the grounds that are transferred from terrain surface-bicycle-rider [7,8]. These movements have the potential for causing disturbances to the central nervous system and have been linked to transient vertigo [6]. However, it is understood that the human body adopts an autonomic strategy to dissipate the majority of these vibrations, apparent by reductions in accelerations prior to reaching the lumbar spine and head [7]. While safer for the user, this reduces overall metabolic efficiency by demanding more energy from the body without contributing to propulsive work [9][10][11][12][13][14][15].Anecdotally, MTB participants stand on their pedals during passage over bumpy terrain in order to alleviate discomfort and presumably to improve performance. While it is known that cyle ergometry in the standing position is energetically more demanding than sitting [16,17] due to the additional demand for postural support, little is understood about such mechanics during MTB where standing could negate the cost of damping impacts and vibrations that occurs.With this in mind, a recent pilot study was completed to assess the efficacy of riding over bumpy terrain in both seated and standing positions. Accelerations in the horizontal and vertical planes were measured in accordance with previous investigations [7,9] across fifteen trials each at a controlled speed with two participants on a rigid MTB. The trials showed greater vertical vibration exposure at the handlebar, wrist and seat post during the standing compared to seated condition (Figure 1).Similar to other studies [7,9], these accelerations were significantly attenuated prior to reaching the lower back and head but interestingly, accelerations were greater for both lumbar and head during the seated trial. This indicates that the body is subjected to greater accelerations whilst negotiating bumpy terrain in a standing position when compared to seated position highlighting some interesting points worth discussing. However, the standing bicyclist is better able to dissipate the energy transferred from surface-terrain and thus reduces the risk of damage to the central nervous system or brain. Figure 1: Mean ± s amplitude (RMS) for vertical accelerations during seated and standing trials. signifies seated position. ⧠ signifies standing position. $$$$ (P<0.0001) main effect of body position; ☠☠☠☠(P<0.0001) main effect of accelerometer location; ★★★★ (p<0.0001) interaction between body position*accelerometer...

Performance and physiological effects of different descending strategies for cross‐country mountain biking

“…Riders who have a higher level of physical fitness tended to recover to a greater extent as seen by the negative correlation between measured in the laboratory and measured during DH R . We surmise that the reduced vibration exposure eventuated to a decreased musculo‐tendonous work requirement (Hurst et al., 2012), which would normally absorb the accelerations in order to protect the head and lumbar spine (Macdermid, 2015; Macdermid et al., 2014b, 2015b, 2016; Miller & Macdermid, 2015). However, as muscle activity was not directly measured, this explanation remains only speculative.…”

“…Wireless, tri‐axial, gyroscopic accelerometers (Emerald, APDM, OR, USA) sampled at 128 Hz were used in a synchronized data logging mode to measure accelerations in accordance with methods reported elsewhere in similar studies (Macdermid et al., 2015b; Macdermid et al., 2016; Miller & Macdermid, 2015). The accelerometers were placed on the lower left arm (frontal distal position); left lower leg (frontal, distal position); seat post (within 10 cm of saddle‐rider contact area); lumbar region of lower back; and medial forehead (Macdermid et al., 2014b).…”