Experienced Cyclists Research Articles

Using an Experimental Bicycle Seat to Reduce Perineal Numbness

ABSTRACTBACKGROUND: Perineal numbness and erectile dysfunction are emerging as health concerns among bicyclists. Three studies indicate that between 7% and 21% of male cyclists experience genital area numbness after prolonged riding.OBJECTIVE: To evaluate the effect of an experimental seat design on perineal numbness.DESIGN: Fifteen experienced male cyclists exercised for 1 hour on a stationary spin cycle using either an experimental or standard bicycle seat. Several days later they repeated the trial using the other seat type. Before and after each 1-hour exercise session, perineal sensation was tested using the Weinstein Enhanced Sensory Testing (WEST)-hand esthesiometer. Cyclists were also asked to report their perception of numbness after each exercise bout.RESULTS: Cyclists reported more numbness with the standard seat than with the experimental seat (79% vs 14%; P=0.009). Similarly, sensory testing at all perineal sites yielded greater hypoesthesia with the standard seat than with the experimental seat (P=0.05). This difference was most marked at the dorsal penis (P=0.04).CONCLUSION: The experimental bicycle seat produced significantly less subjective and objective numbness than the standard cycle seat in 1 hour of stationary cycling. Bicycle seat design and innovation may decrease or eliminate perineal numbness.

Is a joint moment-based cost function associated with preferred cycling cadence?

Eight experienced male cyclists (C), eight well-trained male runners (R), and eight less-trained male noncyclists (LT) were tested under multiple cadence and power output conditions to determine: (1) if the cadence at which lower extremity net joint moments are minimized (cost function cadence) was associated with preferred pedaling cadence (PC), (2) if the cost function cadence increased with increases in power output, and (3) if the association is generalizable across groups differing in cycling experience and aerobic power. Net joint moments at the hip, knee, and ankle were computed from video records and pedal reaction force data using 2-D inverse dynamics. The sum of the average absolute hip, knee, and ankle joint moments defined a cost function at each power output and cadence and provided the basis for prediction of the cadence which minimized net joint moments for each subject at each power output. The cost function cadence was not statistically different from the PC at each power output in all groups. As power output increased, however, the cost function cadence increased for all three subject groups (86 rpm at 100 W, 93 rpm at 150 W, 98 rpm at 200 W, and 96 rpm at 250 W). PC showed little change (R) or a modest decline (C, LT) with increasing power output. Based upon the similarity in the mean data but different trends in the cost function cadence and PC in response to changes in power output as well as the lack of significant correlations between these two variables, it was concluded that minimizing net joint moments is a factor modestly associated with preferred cadence selection.

Simplified deceleration method for assessment of resistive forces in cycling.

The purpose of this study was to develop and test a simplified deceleration technique for measurement of aerodynamic and rolling resistances in cycling. Coast-down tests were performed in level hallways with an experienced cyclist as the rider. Average initial velocities were 2.5-12.8 m x s(-1)) The deceleration technique was simplified by the use on only three switches and a derivation that did not require an assumption that deceleration is constant. The effective frontal area (AC(D)) and coefficient of rolling resistance (CR) were then calculated through a derivation from the equation for resistive forces opposing motion. Method reproducibility was tested by comparison of results for four tests of 30 trials under identical conditions. Method sensitivity was tested by performing 30 trials with three different rider head positions and four different transported mass conditions. Analysis of variance revealed that there were no differences among the results in the reproducibility study for either AC(D) or C(R). Furthermore, the reproducibility tests revealed mean errors of only 0.66% and 0.70% for AC(D) and CR, respectively. ANOVA identified a significant increase (P < 0.001) in rolling resistance with external loading and a significant effect (P < 0.001) of head position on AC(D). Mean (+/-SD) values for AC(D) and C(R) from tests in a racing aeroposture with the head up, the head in line with the trunk, and the head in an intermediate position were 0.304 +/- 0.011, 0.268 +/- 0.010, and 0.262 +/- 0.013 m2, respectively. C(R) averaged 0.00368 in the three head positions. The findings indicate that this simplified deceleration technique is satisfactorily reproducible and sensitive for measurement of aerodynamic and rolling resistances in cycling.

PERFORMANCE IS AFFECTED BY PROPER PLACEMENT OF TRAINING VOLUME DURING TAPERING

387 This study examined the effects of training volume placement during tapering on simulated 20 km time trial (20TT) performance. Eleven experienced cyclists (VO2max=4.20 L.min−1; 60.8 ml.kg−1.min−1) performed an incremental cycle ergometer test to exhaustion on day-1 and a simulated 20TT on day-2, before and after a 7-day taper. Following 4-weeks baseline training (4d per week × 60 min per session), the cyclists were randomly assigned to 3 taper protocols in which training volume (i.e. duration) was reduced by 30 (T30, n=5), 50 (T50, n=6) or 80 percent (T80, n=6) of baseline volume in a systematic fashion. Training intensity during tapering was maintained at 85 percent VO2max in all groups. Respiratory and metabolic measures (VE, VO2, VCO2, HR, RER) were collected every 5 km during the 20TT, and continuously during the incremental test and then averaged every 20 sec. The results showed a significant improvement in simulated 20TT performance time (26:18±1:31 to 25:04±1:36) in the T50 protocol only; as well, rating perceived exertion (p=0.03) and HR (p=0.08) were increased. No other physiological variables examined were significantly different before or after tapering, which was most likely due to the limited sample size. However, these results suggest that a minimal (T30) or an extensive (T80) reduction in training volume during the taper can have a significant affect on performance. This confirms the need for proper placement of training volume during tapering, and, that a systematic reduction in training volume is needed to elicit performance gains. Support: Sport Canada; Malaspina University-College

Reproducibility in simulated 40 km time trial cycling and its associated metabolic stress

This study examined the reproducibility of a simulated 40 km time trial (40TT) repeated on 3 separate occasions prior to pre‐season training. On days 1 (TT1), 3 (TT2) and 5 (TT3), 9 experienced cyclists (X± SD VO2max: 4.27 ± 0.28 L · min−1) performed the 40TT using their own bicycles mounted on wind‐loaded rollers which were mechanically connected to an odometer to record distance cycled. Exercise time and selected metabolic and respiratory measures were recorded at 10 km intervals. The results showed that the mean VO2 (3.57 ±0.50, 3.61 ±0.38, 3.59±0.38L· min−1), cycling velocity (557.4±42.7, 568.3±46.1, 579.8±36.7 m·min−1) and time (min: s; 72:00 ± 5 :20, 70: 50 ± 5:16, 69: 57 ± 4:49) were not different (p < 0.05) between TT1, TT2, TT3, respectively. However, coefficient of variation for time was 3.7%. 40TT cycling intensity was performed at 7% above ventilation threshold of each individual. BLa (mM) was different at only the 10 km interval between TT1 (6.2 ±1.98) vs. TT2 (4.3 ±1.41) and TT3 (4.5 ± 1.63), suggesting that the subjects began TT1 at a higher intensity but were not able to maintain the pace. The intra‐class coefficient ranged between 0.36 and 0.91 for selected variables. The poorest relationship for each was between TT1 vs. TT2 and TT1 vs. TT3. These results suggest that a simulated 40TT adequately assessed the metabolic stress of the cyclists, but that the first attempt was not a valid measure of each subject's performance ability. A learning trial seems important even when assessing experienced, competitive cyclists, prior to pre‐season training.

INFLUENCE OF CADENCE AND POWER OUTPUT ON CYCLING EFFICIENCY IN TRAINED CYCLISTS AND RUNNERS 1122

The goal of this study was to test the hypothesis that trained, experienced cyclists and runners are more efficient at higher cycling cadences. Preferred cadence (PC) was determined in 10 experienced cyclists(VO2max=70.8±4.4 ml/kg/min) and 10 trained runners(72.5±2.2 ml/kg/min) at 3 power outputs (PO; 100, 150, 200 W). Gas exchange was measured on a different day at the same 3 POs and 5 cadences (50, 65, 80, 96, and 110 rpm). Gross (GE) and delta (DE) efficiencies were calculated to determine the influence of cadence and PO on each efficiency measure. PCs of cyclists and runners were similar and did not change appreciably with PO (100 W: 94.7±10.4; 150 W: 94.5±9.7; 200 W: 92.8±7.8 rpm). Cyclists and runners exhibited similar GE at all cadence and PO combinations (p=0.413). For GE there was a significant power x cadence interaction (p<.001) such that as cadence increased GE declined more at 100 W compared to either of the higher POs. Therefore, for GE, cyclists and runners were not more efficient at higher cadences. For DE there was a significant group x cadence interaction (p =.04). In cyclists DE tended to increase with increases in cadence up to 95 rpm, but declined from 95 to 110 rpm, while in runners DE remained relatively unchanged as cadence increased. Cyclists exhibited a higher DE at 95 rpm compared to runners (28.5 vs. 22.9%). Further, the cadence at which DE was maximized (95 rpm) was similar to the PCs of cyclists at each PO. In conclusion cycling experience does not appear to influence GE, but does appear to influence DE. Increases in DE with increasing cadence in cyclists may be due to a specific adaptation, whereby cyclists' leg muscles are contracting closer to the velocity at which muscular efficiency is maximized.

Impotence and nerve entrapment in long distance amateur cyclists.

To assess the frequency and duration of symptoms suggesting peripheral nerve compression after long distance cycling. A questionnaire based cross sectional study among 260 participants in a Norwegian annual bicycle touring race of 540 km. Thirty-five of 160 responding males (22%) reported symptoms from the innervation area of the pudendal or cavernous nerves. Thirty-three had penile numbness or hypaesthesia after the tour. In 10, the numbness lasted for more than one week. Impotence was reported by 21 (13%) of the males. It lasted for more than one week in 11, and for more than one month in three. Both genital numbness and impotence were correlated with weakness in the hands after the ride, a complaint reported by 32 (19%) of all 169 respondents. Forty-six cyclists (30%) indicated paraesthesia or numbness in the fingers, half of them from the ulnar nerve area only. The frequency of impotence, numbness of the penis, hand weakness and sensory symptoms from the fingers in bicycle sport may be higher than hitherto recognized. It afflicts both experienced cyclists and novices. In some, the complaints may last up to eight months. Besides changing the hand and body position on the bike, restricting the training intensity, and taking ample pauses may also be necessary in prolonged and vigorous bicycle riding to prevent damage to peripheral nerves.

Analysis of Stated Preferences for Intermodal Bicycle-Transit Interfaces

One proposed means of increasing use of both transit and bicycles is to replace long automobile trips with “bike and ride” trips. In this study, a stated-preference survey was conducted using hypothetical scenarios within which respondents ranked their preferences for making a work trip by automobile only, park and ride, or bike and ride. The survey addressed numerous potential factors that might influence this choice, including three policy variables that were systematically varied in the scenarios: on-street bicycle facility type, bicycle parking facility type, and bicycle access distance to transit. The survey data are summarized and used to estimate discrete choice models. A nested logit choice model was developed as the preferred model. From this model, inferences are drawn about many factors. Conclusions are drawn about the three main policy variables. In short, the results support the notion that bicycle lockers are the preferred parking facility to increase bike and ride use. The results also indicate that bike lanes are superior to wide curb lanes as an incentive for casual and inexperienced cyclists, but that bike lanes and wide curb lanes are an identical incentive for experienced cyclists.

Isometric Cervical Extension Strength of Recreational and Experienced Cyclists

The effect for cyclists of the typical forward sitting position on neck strength and its possible relationship to neck pain have not been examined. The purpose of this study was to measure the peak isometric cervical extension strength (PICES) of both recreational and experienced road cyclists and to compare these values to those of noncyclists. Subjects, 45 men between the ages of 18 and 40, were tested for voluntary PICES through a 126 degrees range of motion on a MedX cervical extension machine. No significant differences were found between the three groups in PICES at any angle. When expressed relative to body weight, significant differences in PICES were found at 126 degrees between the control group and the recreational cyclist group (p < 0.05), and between the control group and the experienced cyclist group (p < 0.01), but not at any other angle. Furthermore, no significant differences in strength were found between cyclists experiencing neck pain and those who did not. These data indicate that the cervical muscles of cyclists have not adapted by increasing maximal isometric strength above that of noncyclists, and that the neck pain frequently reported may be due to fatigue from sustained muscular contractions associated with time spent cycling, rather than from muscle weakness.

The Laboratory Assessment of Endurance Performance in Cyclists

Performance in endurance activities depends on maximal aerobic capacity (VO2max) and the ability to sustain a high percentage of VO2max over time. This study examined whether noninvasive laboratory measures would be valid predictors of endurance performance in an individual-start bicycle race (TT). Eight experienced male cyclists (age = 25.1 +/- 3.3 years, weight = 75.0 +/- 5.7 kg, VO2max = 5.05 +/- 0.4 L.min-1) performed a progressive incremental exercise test to exhaustion on a cycle ergometer. VO2max, maximum power output, and ventilatory threshold were determined. Later the subjects completed a 40-km TT. Power output at the ventilatory threshold (VT watts) was correlated with race performance time and calculated power output during the competition (r = -0.81; r = 0.82). VT watts and VO2max accounted for 75% of the variance between subjects (r = 0.91) in performance time. These data indicate that simple laboratory measures can predict TT performance in trained cyclists. Individual differences may be accounted for by motivation, aerodynamic position, and efficiency.

Hypervolemia and cycling time trial performance

Ten experienced cyclists rode three simulated time trials to determine whether hypervolemia was associated with improvements in cycling time trial performance. The conditions were: exercise-induced hypervolemia (ExH), dextran-induced hypervolemia (DxH), and euvolemia (Eu). ExH was induced by 3 d of submaximal cycling lasting an average of 92.9 min at an average relative intensity of 68%. DxH was induced by acute plasma volume expansion with 400 +/- 121 ml of a 6% dextran solution. Compared with Eu, ExH and DxH were associated with 9.4% and 8.7% elevations in blood volume as well as 11.1% and 12.4% elevations in plasma volume, respectively. Performance was significantly improved (P < 0.05) (i.e., target work goal reached earlier) during ExH (81.41 +/- 5.52 min) and DxH(81.36 +/- 5.06 min) than during Eu (90.87 +/- 5.27 min). Average power was significantly higher during E x H (246 +/- 13 W) and DxH (245 +/- 14 W) than during Eu (221 +/- 15 W). There were no significant differences in performance time or average power between the two hypervolemic conditions. Average sweat rates were significantly elevated during ExH (22.6 +/- 1.4 ml.min-1) and DxH (22.2 +/- 1.6 ml.min-1) than during Eu (20.4 +/- 1.7 ml.min-1). Rectal temperatures rose from approximately 37.2-39.2 degrees C during each time trial but there were no significant differences in T(re) between trials. In conclusion, hypervolemia, whether induced by short-term training or dextran-infusion, had a beneficial effect on performance and average power during simulated time trials lasting approximately 90 min. These improvements in performance were related to hypervolemia rather than other short-term training adaptations.

Effect of cadence on the economy of uphill cycling

Competitive cyclists generally climb hills at a low cadence despite the recognized advantage in level cycling of high cadences. To test whether a high cadence is more economical than a low cadence during uphill cycling, nine experienced cyclists performed steady-state bicycling exercise on a treadmill under three randomized trials. Subjects bicycled at 11.3 km.h-1 up a 10% grade while 1) pedalling at 84 rpm in a sitting position-84 Sit, 2) pedalling at 41 rpm in a standing position-41 Stand, and 3) pedalling at 41 rpm in a sitting position-41 Sit. Heart rate (HR), oxygen consumption (VO2), ventilation (VE), and respiratory exchange ratio were measured continuously during 5-min trials and averaged over the last 2 min. Additionally, rating of perceived exertion was recorded during the fifth minute of each trial, and blood lactate concentration was recorded immediately before and after each trial. Significantly lower values for HR, VO2 and VE were recorded during 84 Sit (164 +/- 3 bpm, 51.8 +/- 0.8 ml.min-1 x kg-1, 94 +/- 5 l.min-1) than for either the 41 Stand (171 +/- 2 bpm, 53.1 +/- 0.7 ml.min-1 x kg-1, 105 +/- 6 l.min-1) o 41 Sit (168 +/- 2 bpm, 53.1 +/- 0.8 ml.min-1 x kg-1, 101 +/- 6 l.min-1) trials. No other differences were noted between trials for any of the measured variables. We conclude that uphill cycling is more economical at a high versus a low cadence.

The constrained control of force and position in multi-joint movements

In many arm or leg movements the hand or foot has to exert an external force on the environment. Based on an inverse dynamical analysis of cycling, it is shown that the distribution of net moments in the joints needed to control the direction of the external force is often opposite to the direction of joint displacements associated with this task. Kinetic and kinematic data were obtained from five experienced cyclists during ergometer cycling by means of film analysis and pedal force measurement. An inverse dynamic analysis, based on a linked segments model, yielded net joint moments, joint powers and muscle shortening velocities of eight leg muscles. Activation patterns of the muscles were obtained by means of surface electromyography. The results show that the transfer of rotations in hip, knee and ankle joints into the translation of the pedal is constrained by conflicting requirements. This occurs between the joint moments necessary to contribute to joint power and the moments necessary to establish a direction of the force on the pedal which allows this force to do work on the pedal. Co-activation of mono-articular agonists and their bi-articular antagonists appear to provide a unique solution for these conflicting requirements: bi-articular muscles appear to be able to control the desired direction of the external force on the pedal by adjusting the relative distribution of net moments over the joints while mono-articular muscles appear to be primarily activated when they are in the position to shorten and thus to contribute to positive work. Examples are given to illustrate the universal nature of this constrained control of force (external) and position (joint). Based on this study and published data it is suggested that different processes may underlie the organization of the control of mono- and bi-articular muscles.

EMG profiles of lower extremity muscles during cycling at constant workload and cadence

Limited conclusions concerning the variability in EMG patterns during cycling can be made from available data in the literature because of methodological differences which include electrode placement and experimental design. The purpose of this study was to monitor EMG signals from ten lower extremity muscles over a large number of pedalling cycles in experienced cyclists at constant workload and cadence. Variability across subjects was evaluated by calculating the coefficient of variation (CV) at 10% intervals of the pedalling cycle. Within subject EMG patterns were very consistent within a single trial. The single-joint hip and knee extensors (gluteus maximus, vastus medialis, and vastus lateralis) had the lowest CV values (less than 30%). This low variability appears to support their role as power generators. Variability was generally higher in the hamstring muscles with two biceps femoris patterns emerging despite relatively similar experimental conditions. EMG signals from surface and fine wire electrodes for the hamstring muscles were compared for possible contribution to the discrepancies in the EMG profiles. Fine wire EMG data were quite similar to those obtained using surface electrodes, indicating that crosstalk had minimal effect, in general, on the hamstring signals. The tibialis anterior, gastrocnemius, and soleus muscles displayed fairly repeatable patterns, with variability highest in the first 20% of the pedalling cycle for all muscles studied.

Aerodynamic Handlebars: Rider Arrives Before Bicycle

To the Editor. —A radical advance in bicycle handlebars has allowed riders to increase their speed by adopting a more aerodynamic position (Figure). This was most dramatically demonstrated by Greg Lemond's victories in the Tour de France. The publicity generated by this race has led significant numbers of cyclists to add these bars to their bicycles. This development may have serious health risks. One of us (R.A.Y.), an experienced cyclist, was traveling downhill at 50 km/h when he fell from the bicycle, suffering multiple facial injuries and a tripod fracture of the zygoma, despite wearing a helmet. These bars present an increased danger for several reasons: (1) they allow relatively novice riders to attain higher speeds; (2) they are usually ridden in a position that does not allow quick access to brake levers; (3) they change the weight distribution of the rider to one that is significantly less stable than

Effects of seat height changes on joint force and moment patterns in experienced cyclists

Effects of seat height changes on joint force and moment patterns in experienced cyclists