The Effects of Vibrations Experienced during Road vs. Off-road Cycling

Abstract

The purpose of this investigation was to compare the effects of vibrations experienced during off-road and road cycling. It was hypothesised that additional damping will be expressed through a greater work demand and increased physiological markers when travelling at the same speed over an identical terrain profile. Participants ascended a tar-sealed road climb and a single-track off-road climb at a predetermined speed. Time, speed, power, cadence, heart rate and V̇ O2 were sampled and logged every second while tri-axial accelerometers recorded accelerations (128 Hz) to quantify vibrations experienced. Statistical analysis indicated accelerations to be greater during the off-road condition (p<0.0001) with post-hoc analysis exposing differences (p<0.001) for handlebar, arm, leg and seat post but not the lower back or head. The increased accelerations during off-road riding are associated with the increased vibrations and rolling resistance experienced. This led to increases in the work done (road: 280±69 vs. off-road: 312±74 W, p=0.0003) and, consequentially, a significant increase in the physiological markers V̇ O2 (road: 48.5±7.5 off-road 51.4±7.3 ml·kg(-1)·min(-1), p=0.0033) and heart rate (road: 161±10 off-road 170±10 bpm, p=0.0001) during the off-road condition. Such physiological differences and their causes are important to understand in order to provide suitable training recommendations or technological interventions for improving competitive performance or recreational enjoyment.

Ergonomic Strategies Related To Health and Efficiency in Mountain Biking

“…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, 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].…”

“…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.…”

“…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.…”

“…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.…”