The BMX start is one of the most important aspects of BMX racing and has been deemed by coaches as one of the strongest determining factors of finish line placing. The present study analysed the correlation between elite BMX riders and their relative position at the start of a BMX race in relation to finish line placing. Data from 348 riders results in 175 elite races in the four 2012 Union Cycliste Internationale (UCI) world cup events were analysed. Time gates were placed in four positions around each BMX track and the data sets were analysed using Kendall's tau-b bivariante correlation. A strong correlation was established at the second time gate for both males (t=0.581, P<0.01) and females (t=0.571, P<0.01). The correlation between riders' final placing was greater in positions 1st to 3rd (t=0.586, P <0.01. 4th to 8th t=0.249, P <0.01) compared to riders placed 4th to 8th (t=0.519, P <0.01. 4th to 8th t=0.372, P <0.01.) for both male and female riders respectively. In conclusion, a strong correlation exists between riders position 8-10 s into a race. Therefore, focusing on a riders' ability to gain placings at the start of a race will have an effect on their finish line position.

Objectives To investigate the influence of BMX helmets and neck braces on translational and rotational accelerations in youth riders. Design Mixed model, repeated measure and correlation. Methods Twenty three competitive youth BMX riders classified by age group (6–9 years, 10–13 years and 14–18 years) completed 6 laps of an indoor BMX track at race pace, 3 laps without a neck brace (NB) and 3 without brace (WB). A triaxial accelerometer with gyroscope was placed behind the right ear to determine the mean number of accelerations, translational and rotational, of the head between conditions and by age group. Results Significant reductions by condition (p = 0.02) and by age (p = 0.04) were found for the number of accelerations, though no interactions (condition × age) were revealed. Significant increases by age (p = 0.01) were revealed for translational accelerations, whilst significant increases by condition (p = 0.02) were found for rotational accelerations. In addition, significant correlations were revealed between relative helmet mass and age (r = 0.83; p = 0.001) and relative helmet mass and number of accelerations (r = 0.46; p = 0.03). Conclusions Accelerations at the head decreased with increased age, possibly due to the influence of greater stabilising musculature. Additionally, neck braces also significantly reduced the number of accelerations. However, the magnitude of accelerations may be influenced by riding dynamics. Therefore, the use of neck braces combined with strength work to develop neck strength, could aid in the reduction of head accelerations in youth BMX riders.

The aim of the current study was to determine if a technique called "pumping" had a significant effect on velocity production in Bicycle Motocross (BMX) cycling. Ten National standard male BMX riders fitted with surface electromyography (sEMG) sensors completed a timed lap of an indoor BMX track using the technique of pumping, and a lap without pumping. The lap times were recorded for both trials and their surface sEMG was recorded to ascertain any variation in muscle activation of the biceps brachii, triceps brachii, vastus lateralis, and medial gastrocnemius. The findings revealed no significant differences between any of muscle groups (p > 0.05). However, significant differences (p < 0.001) were observed between the pumping and nonpumping trials for both mean lap velocity (42 ± 1.8 km·h, 33 ± 2.9 km·h, respectively) and lap times (43.3 ± 3.1 seconds, 34.7 ± 1.49 seconds, respectively). The lap times recorded for the pumping trials were 19.50 ± 4.25% lower than the nonpumping, whereas velocity production was 21.81 ± 5.31% greater in the pumping trial compared with the nonpumping trial. The technique of pumping contributed significantly to velocity production, although not at the cost of additional muscle activity. From a physiological and technical perspective, coaches and riders should prioritize this technique when devising training regimes.

This study evaluated the effects of ingesting sodium bicarbonate (NaHCO3) or caffeine individually or in combination on high-intensity cycling capacity. In a counterbalanced, crossover design, 13 healthy, noncycling trained males (age: 21 ± 3 years, height: 178 ± 6 cm, body mass: 76 ± 12 kg, peak power output (Wpeak): 230 ± 34 W, peak oxygen uptake: 46 ± 8 mL·kg(-1)·min(-1)) performed a graded incremental exercise test, 2 familiarisation trials, and 4 experimental trials. Trials consisted of cycling to volitional exhaustion at 100% Wpeak (TLIM) 60 min after ingesting a solution containing either (i) 0.3 g·kg(-1) body mass sodium bicarbonate (BIC), (ii) 5 mg·kg(-1) body mass caffeine plus 0.1 g·kg(-1) body mass sodium chloride (CAF), (iii) 0.3 g·kg(-1) body mass sodium bicarbonate plus 5 mg·kg(-1) body mass caffeine (BIC-CAF), or (iv) 0.1 g·kg(-1) body mass sodium chloride (PLA). Experimental solutions were administered double-blind. Pre-exercise, at the end of exercise, and 5-min postexercise blood pH, base excess, and bicarbonate ion concentration ([HCO3(-)]) were significantly elevated for BIC and BIC-CAF compared with CAF and PLA. TLIM (median; interquartile range) was significantly greater for CAF (399; 350-415 s; P = 0.039; r = 0.6) and BIC-CAF (367; 333-402 s; P = 0.028; r = 0.6) compared with BIC (313: 284-448 s) although not compared with PLA (358; 290-433 s; P = 0.249, r = 0.3 and P = 0.099 and r = 0.5, respectively). There were no differences between PLA and BIC (P = 0.196; r = 0.4) or between CAF and BIC-CAF (P = 0.753; r = 0.1). Relatively large inter- and intra-individual variation was observed when comparing treatments and therefore an individual approach to supplementation appears warranted.

This study aimed to investigate the influence of different mountain bike wheel diameters on muscle activity and whether larger diameter wheels attenuate muscle vibrations during cross-country riding. Nine male competitive mountain bikers (age 34.7 ± 10.7 years; stature 177.7 ± 5.6 cm; body mass 73.2 ± 8.6 kg) participated in the study. Riders performed one lap at race pace on 26, 27.5 and 29 inch wheeled mountain bikes. sEMG and acceleration (RMS) were recorded for the full lap and during ascent and descent phases at the gastrocnemius, vastus lateralis, biceps brachii and triceps brachii. No significant main effects were found by wheel size for each of the four muscle groups for sEMG or acceleration during the full lap and for ascent and descent (P > .05). When data were analysed between muscle groups, significant differences were found between biceps brachii and triceps brachii (P < .05) for all wheel sizes and all phases of the lap with the exception of for the 26 inch wheel during the descent. Findings suggest wheel diameter has no influence on muscle activity and vibration during mountain biking. However, more activity was observed in the biceps brachii during 26 inch wheel descending. This is possibly due to an increased need to manoeuvre the front wheel over obstacles.

The aims of this study were to analyse the optimal cadence for peak power production and time to peak power in bicycle motocross (BMX) riders. Six male elite BMX riders volunteered for the study. Each rider completed 3 maximal sprints at a cadence of 80, 100, 120 and 140 revs · min(-1) on a laboratory Schoberer Rad Messtechnik (SRM) cycle ergometer in isokinetic mode. The riders' mean values for peak power and time of power production in all 3 tests were recorded. The BMX riders produced peak power (1105 ± 139 W) at 100 revs · min(-1) with lower peak power produced at 80 revs · min(-1) (1060 ± 69 W, (F(2,15) = 3.162; P = .266; η(2) = 0.960), 120 revs · min(-1) (1077 ± 141 W, (F(2,15) = 4.348; P = .203; η(2) = 0.970) and 140 revs · min(-1) (1046 ± 175 W, (F(2,15) = 12.350; P = 0.077; η(2) = 0.989). The shortest time to power production was attained at 120 revs · min(-1) in 2.5 ± 1.07 s. Whilst a cadence of 80 revs · min(-1) (3.5 ± 0.8 s, (F(2,15) = 2.667; P = .284; η(2) = 0.800) 100 revs · min(-1) (3.00 ± 1.13 s, (F(2,15) = 24.832; P = .039; η(2) = 0.974) and 140 revs · min(-1) (3.50 ± 0.88 s, (F(2,15) = 44.167; P = .006; η(2) = 0.967)) all recorded a longer time to peak power production. The results indicate that the optimal cadence for producing peak power output and reducing the time to peak power output are attained at comparatively low cadences for sprint cycling events. These findings could potentially inform strength and conditioning training to maximise dynamic force production and enable coaches to select optimal gear ratios.

The aim of this study was to analyze the production of velocity in bicycle motocross (BMX) compared to other cycling disciplines. Six elite BMX riders, 5 males and 1 female who competed and trained regularly for a period of 12 yrs ± 2 agreed to take part in this study. Each rider performed 3, 50-m sprint tests and a single 200 m fatigue test. The riders’ peak power, fatigue index, power to weight ratio, and cycling revolution per minute were analyzed using a Schoberer Rad Messtechnik (SRM) BMX power meter. The BMX riders’ peak power and power to weight ratio were all found to be similar to those in other sprint cycling events. Peak power outputs of 1539 ± 148 W and 1030 W were recorded with mean power to weight ratios of 21.29 ± 0.84 W·kg-1 and 16.65 W·kg-1 . The BMX riders’ power fatigue index was found to be higher than other sprint events as riders fatigued at a greater rate. Mean fatigue index was 61.19 ± 5.97 W·sec-1 for the male riders and 53.04 W·sec-1 for the female rider. A notable finding of this study was the relationship of cycling cadence (rev·min-1 ), peak power (Watts) and velocity (mi·h-1 ). This relationship suggests once a BMX rider achieves peak power their pedaling cadence becomes the major contributory factor to velocity production.

PURPOSE: The purpose of this study was to investigate whether high-intensity cycling training leads to adapted responses of balance performance in response to exercise-induced muscle fatigue. METHODS:Eighteen healthy adults were assigned to either 3-weeks (n = 8, age 20.1 ± 2.6 years, height 177 ± 5 cm, mass 73.6 ± 5.1 kg) or 6-weeks (n = 10, age 24.3 ± 5.8 years, height 179 ± 6 cm, mass 81.0 ± 15.8 kg) of high-intensity training (HIT) on a cycle ergometer. The centre of pressure (COP) displacement in the anteroposterior (COPAP) direction and COP path length (COPL) were measured before and after the first and final high-intensity training sessions. RESULTS:Pre-training, exercise-induced fatigue elicited an increase in COPAP (3-weeks; p = 0.001, 6-weeks; p = 0.001) and COPL (3-weeks; p = 0.002, 6-weeks; p = 0.001) returning to pre-exercise levels within 10-min of recovery. Following 3-weeks of training, significant increases in COPAP (p = 0.001) and COPL (p = 0.002) were observed post-fatigue, returning to pre-exercise levels after 15-min of recovery. After 6-weeks of training no significant increases in sway (COPAP; p = 0.212, COPL; p = 0.998) were observed following exercise-induced fatigue. CONCLUSIONS: In summary, 3 weeks of HIT resulted in longer recovery times following fatigue compared to pre-training assessments. After 6 weeks of HIT, postural sway following fatigue was attenuated. These results indicate that HIT could be included in injury prevention programmes, however, caution should be taken during early stages of the overreaching process.

The aim of this study was to ascertain the variation in elite male bicycle motocross (BMX) cyclists' peak power, torque, and time of power production during laboratory and field-based testing. Eight elite male BMX riders volunteered for the study, and each rider completed 3 maximal sprints using both a Schoberer Rad Messtechnik (SRM) ergometer in the laboratory and a portable SRM power meter on an Olympic standard indoor BMX track. The results revealed a significantly higher peak power (p ≤ 0.001, 34 ± 9%) and reduced time of power production (p ≤ 0.001, 105 ± 24%) in the field tests when compared with laboratory-derived values. Torque was also reported to be lower in the laboratory tests but not to an accepted level of significance (p = 0.182, 6 ± 8%). These results suggest that field-based testing may be a more effective and accurate measure of a BMX rider's peak power, torque, and time of power production.

The aim of this study was to ascertain if gear ratio selection would have an effect on peak power and time to peak power production in elite Bicycle Motocross (BMX) cyclists. Eight male elite BMX riders volunteered for the study. Each rider performed three, 10-s maximal sprints on an Olympic standard indoor BMX track. The riders' bicycles were fitted with a portable SRM power meter. Each rider performed the three sprints using gear ratios of 41/16, 43/16 and 45/16 tooth. The results from the 41/16 and 45/16 gear ratios were compared to the current standard 43/16 gear ratio. Statistically, significant differences were found between the gear ratios for peak power (F(2,14) = 6.448; p = .010) and peak torque (F(2,14) = 4.777; p = .026), but no significant difference was found for time to peak power (F(2,14) = 0.200; p = .821). When comparing gear ratios, the results showed a 45/16 gear ratio elicited the highest peak power,1658 ± 221 W, compared to 1436 ± 129 W and 1380 ± 56 W, for the 43/16 and 41/16 ratios, respectively. The time to peak power showed a 41/16 tooth gear ratio attained peak power in -0.01 s and a 45/16 in 0.22 s compared to the 43/16. The findings of this study suggest that gear ratio choice has a significant effect on peak power production, though time to peak power output is not significantly affected. Therefore, selecting a higher gear ratio results in riders attaining higher power outputs without reducing their start time.