Ergonomic Interventions, Health and Injury Prevention during Off-Road Mountain Biking

Abstract

EditorialHalf of all Americans participated in outdoor recreation activities during 2013, of which 16% or 46.6 million (older than 6 yrs) take part in cycling (Road, Mountain bike, or BMX). Excursions totalled at 2.7 billion and ranked it 2 nd for number of outings (887.9 million) for ages 6-17 yrs [1]. This presents a positive picture in regards to health promotion, yet there are concerns regarding bone health and excessive time spent in a weight supported position in road cyclists [2]. On the other hand, mountain bikes are the most popular bike ridden in the western world [3]. This discipline of cycling not only improves cardiovascular health, but also provides an osteogenic effect greater than both road cycling and normal recreational activity [4].However, this sport does come with it's own risk and the overall injury rate is classed as very high, with 16.8 injuries per 1,000 h exposure [5]. While the majority of these injuries are acute, traumatic, and isolated to the minority [3], it is expected that many overuse injuries are not reported. This is supported by data showing 51.4% of participants completing an endurance mountain bike race suffered symptoms of overuse, particularly in the lower back, buttocks, knees and wrists [6]. Similarly, participants exposed to 4h of intense mountain biking suffered benign paroxysmal positional vertigo without any prior symptoms [7].Purportedly, such negative effects are primarily due to the nonpropulsive work demand caused by shock attenuation, a consequence of negotiating obstacles, and the continuous damping of vibrations. These vibrations are produced via the interaction of tyre surface area with trail surface [8] and are the very same thing that promote the sports osteogenic effect [4]. As such, the vibrations mountain bikers are exposed to are complex in nature, containing many frequencies (generally <50 Hz) in all directions and ranging in amplitude (rms) from 15-20 m·s -1 at the handlebar and 20-30 m·s -1 at the seat post [8].The energy from such oscillating movements must be absorbed or else result in little or no wheel contact, albeit for a very short period of time. Even so, during these small epochs, the transfer of energy from the drive mechanism to the tyre-trail surface interaction cannot occur.In order to negate this negative effect, the bikes mechanical parts and bike rider's soft tissue, absorbs energy in a damping mechanism enabling more efficient forward momentum and thus prevents injury to the axial skeleton. This occurs in the mechanical-biological system, particularly at the point of contact including handlebar-arm; pedalfoot-leg; and saddle-lower back [8]. It is reflected by an increase in upper body muscular work done [9] and likely plays a part in overall decreased economy during off-road compared to road cycling. The continuous nature of which leads to overuse injuries at the joints.Therefore, the challenge for the mountain bike industry is to provide a bicycle that interacts in the most efficient and safe manner with regards to performance and ...

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.…”

Ergonomic Strategies Related To Health and Efficiency in Mountain Biking

“…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].…”

“…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].…”

Design of hydraulic bottom-out control for mountain bike suspension

“…Hence, use of suspension translates to better braking performance, cornering and predictability of the bicycle. Thirdly, by absorbing energy, suspension can reduce the risk of injury due to impacts being transmitted through the bicycle (Macdermid 2015(Macdermid , 2017. This 'fatigue theory' exploring the increased comfort achieved when using suspension has been studied to the largest extent and is expanded below.…”

“…This highlights the importance of well performing suspension on downhill mountain bikes. Macdermid (2015) contends that the high overall injury rate in mountain biking and in particular lower back, neck and wrist pain can be partly attributed to riders' exposure to complex vibrations varying in frequency, direction and amplitude. Additionally, experiments have found that of the energy used by the rider to power the bicycle, the amount dissipated by suspension is negligible on most uneven terrain (Ishii et al 2003).…”