The purpose was to assess the mechanical work and physiological responses to cross country mountain bike racing. Participants (n = 7) cycled on a cross country track at race speed whilst O₂, power, cadence, speed, and geographical position were recorded. Mean power during the designated start section (68.5 ± 5.5 s) was 481 ± 122 W, incurring an O₂ deficit of 1.58 ± 0.67 L – min⁻¹ highlighting a significant initial anaerobic (32.4 ± 10.2%) contribution. Complete lap data produced mean (243 ± 12 W) and normalised (279 ± 15 W) power outputs with 13.3 ± 6.1 and 20.7 ± 8.3% of time spent in high force-high velocity and high force-low velocity, respectively. This equated to, physiological measures for % O_2max (77 ± 5%) and % HR_max (93 ± 2%). Terrain (uphill vs downhill) significantly (P < 0.05) influenced power output (70.9 ± 7.5 vs 41.0 ± 9.2% W_max),the distribution of low velocity force production, O₂ (80 ± 1.7 vs 72 ± 3.7%) and cadence (76 + 2 vs 55 ± 4 rpm) but not heart rate (93.8 ± 2.3 vs 91.3 ± 0.6% HR_max) and led to a significant difference between anaerobic contribution and terrain (uphill, 6.4 ± 3.0 vs downhill, 3.2 ± 1.8%, respectively) but not aerobic energy contribution. Both power and cadence were highly variable through all sections resulting in one power surge every 32 s and a supra-maximal effort every 106 s. The results show that cross country mountain bike racing consists of predominantly low velocity pedalling with a large high force component and when combined with a high oscillating work rate, necessitates high aerobic energy provision, with intermittent anaerobic contribution. Additional physical stress during downhill sections affords less recovery emphasised by physiological variables remaining high throughout.

The ability to quantify power within the sport of slalom kayaking would provide coaches and athletes objective data to monitor performance. This study determined the validity of a kayak paddle power meter and subsequent relationship between work rate and stroke kinetics. One participant completed multiple trials of a flat-water, straight-line sprint and a sequence of slalom gates at numerous intensities to attain the velocity:power relationship. Laboratory results identified the kayak paddles’ strain gauges were valid and reliable, and field tests presented a cubic relationship for power as a function of velocity in the straight-line sprint (R²=0.982) and the slalom-specific test (R²=0.993). Further analysis of stroke kinetics identified velocity of hand movement at individual peak force capability to be critical in the highest work rates achieved for both slalom and flat-water sprinting. It was concluded that the kayak paddle power meter tested is a valid means of recording work rate and stroke kinetics during kayaking in the field.

The purpose of this study was to assess the physical work demand in relation to metrics of force and subsequent physiological response to a simulated flat water slalom competition. Eight New Zealand junior/senior team members completed a standard incremental step-test to ascertain power:oxygen consumption relationship followed by a simulated race run whilst breath-by-breath analysis along with force and power data logged at 50Hz in order to determine stroke length, impulse, peak force, time to peak force and rate of peak force per stroke. Physiological response to negotiating a flat water slalom course was greater than straight-line paddling (36.89 ± 2.01 vs 32.17 ± 1.97 ml∙kg-1∙min-1, p=0.0065) at the same power output. Mean power output for the duration of the simulated race (91.63 ± 7.19 s) was 203.8 ± 45.0 W, incurring an oxygen deficit of 1.386 ± 0.541 L∙min-1 translating to an overall anaerobic contribution of 32 ± 18 % and aerobic contribution of 68 ± 18 %. Moderate to strong relationships between time duration and stroke peak force (R2=0.354, R2=0.485) and rate of peak force development (R2=0.345, R2=0.426) but not for stroke length (R2=0.022, R2=0.012), impulse (R2=0.088, R2=0.097) or time to peak force (R2=0.001, R2=0.0001) for left and right strokes, respectively. The number of propulsive (0.6 s) strokes with a ratio of 94:6 %. Longer stroke duration was significantly correlated to greater impulse (R2=0.507, p<0.0001) and time to peak force (R2=0.851, p<0.0001), but a lower rate of force development (R2=0.107, p<0.0001). The results show that a flat water slalom under simulated race conditions entails initial supra-maximal (anaerobic) work rate with a subsequent transition to one associated with maximal aerobic capacity. Inability to sustain work done and the subsequent decline in peak force and force profile per stroke requires further research regarding strategies to enhance performance.

Non-propulsive work demand has been linked to reduced energetic economy of cross-country mountain biking. The purpose of this study was to determine mechanical, physiological and performance differences and observe economy while riding a downhill section of a cross-country course prior to and following the metabolic “load” of a climb at race pace under two conditions (hardtail and full suspension) expected to alter vibration damping mechanics. Participants completed 1 lap of the track incorporating the same downhill section twice, under two conditions (hardtail and full suspension). Performance was determined by time to complete overall lap and specific terrain sections. Power, cadence, heart rate and oxygen consumption were sampled and logged every second while triaxial accelerometers recorded accelerations (128 Hz) to quantify vibration. No differences between performance times (P = 0.65) or power outputs (P = 0.61) were observed while physiological demand of loaded downhill riding was significantly greater (P < 0.0001) than unloaded. Full suspension decreased total vibrations experienced (P < 0.01) but had no effect on performance (P = 0.97) or physiological (P > 0.05) measures. This study showed minimal advantage of a full suspension bike in our trial, with further investigations over a full race distance warranted.

Physiological parameters and muscle activity of jockeys may affect their fall and injury risk, performance, and career longevity, as well as the performance and welfare of the horses they ride. Therefore, this study aimed to quantify the physiological demands, body displacement, and electromyographic (EMG) activity of twelve jockeys riding 52 trials and 16 professional races. The jockeys were instrumented with heart rate (HR) monitors, accelerometers, and integrated EMG clothing (recording eight muscle groups: quadriceps, hamstrings, gluteal, erector spinae/lower back, abdominal external obliques, abdominal, trapezial and pectoral) which recorded continuously whilst riding. During race day, jockeys rode an average of 5 ± 4 trials and 4 ± 2 races over 2–2.5 h. The trials represented lower intensity cardiovascular demand (~81% HRmax) and Training Impulse (TRIMP) scores (4.4 ± 1.8) than races at maximal intensity effort (~94% HRmax, 7.2 ± 1.8 TRIMP, p < 0.05). Jockey head displacement was similar in trials (5.4 ± 2.1 cm) and races (5.6 ± 2.2 cm, p > 0.05), with more vertical (6.7 ± 2.7 cm) and less medio/lateral (2.3 ± 0.7 cm) and fore/aft (3.7 ± 1.6 cm) displacement for jockeys riding in trials than races (5.5 ± 2.3, 2.8 ± 1.0, 5.6 ± 2.5 cm, p < 0.05). Jockeys in races adopted a lower crouched posture, with their centre of mass (COM) shifted anteriorly, using greater hamstring activation and less upper arm muscle activation than in trials. The differences in riding posture and physiological demands on jockeys riding in a race rather than a trial, highlight the requirement for an off-horse race-specific training programme to improve jockey fitness and performance. Greater jockey stability and coordination will have mutual benefits for both horse welfare and performance.