Experienced Cyclists Research Articles

Biomechanical effects of different treatment modalities used in knee pain during cycling

Background: Little work has been undertaken on the biomechanical effects of patellofemoral taping and bracing in cycling. Objective: The purpose of the study was to assess the three-dimensional movement of the knee joint at different levels of resistance, across four treatment conditions, in experienced cyclists and discuss the clinical implications of the findings. Method: 15 healthy male subjects were asked to conduct four separate tests at three separate resistances on a static trainer. Each test used a different treatment modality. The order of testing was randomised a) no intervention, b) placebo patella taping, c) a patellofemoral brace, d) McConnell patella taping. Kinematic data were collected using a 10 camera ProReflex motion analysis system. Reflective markers were placed on the foot, shank, thigh and pelvis using the CAST technique. Results: A repeated measures two-way ANOVA test was performed together with posthoc Pairwise comparison with Bonferroni adjustment to examine the difference in three dimensional movement under the different conditions. Results (small significant differences) were presented in ROM tables for clinical application and relevance. Extension (1-2 p=0.002, 1-3 p= 0.003, 2-3 p= 0.004). Coronal plane between brace and neutral taping (p= 0.033) also between resistances 1 & 3 and 2 & 3 (p= 0.035, p=0.011). Transverse plane (p= 0.028) between Brace and McConnell taping. Conclusion: If changes in the cycling movement patterns are required in clinical treatment, then taping or bracing may possibly affect this. However, a full understanding of an individual’s biomechanical movement and cycling position is required as generic adaptations that do not take into account position, cadence, skin/fabric movement and power, and may be counterproductive. This study provides some initial understanding of the possible effects of bracing and taping in experienced cyclists, the application of taping may alter the biomechanics of the cycling action. Taping seems to initiate changes in ROM but as yet it is unclear as to its implication with respect to pain reduction. This study also helps us to understand that bracing is both impractical and any resultant changes during cycling are unlikely to be measurable.

Influence of road incline and body position on power–cadence relationship in endurance cycling

In race cycling, the external power-cadence relationship at the performance level, that is sustainable for the given race distance, plays a key role. The two variables of interest from this relationship are the maximal external power output (P (max)) and the corresponding optimal cadence (C (opt)). Experimental studies and field observations of cyclists have revealed that when cycling uphill is compared to cycling on level ground, the freely chosen cadence is lower and a more upright body position seems to be advantageous. To date, no study has addressed whether P (max) or C (opt) is influenced by road incline or body position. Thus, the main aim of this study was to examine the effect of road incline (0 vs. 7%) and racing position (upright posture vs. dropped posture) on P (max) and C (opt). Eighteen experienced cyclists participated in this study. Experiment I tested the hypothesis that road incline influenced P (max) and C (opt) at the second ventilatory threshold ([Formula: see text] and [Formula: see text]). Experiment II tested the hypothesis that the racing position influenced [Formula: see text], but not [Formula: see text]. The results of experiment I showed that [Formula: see text] and [Formula: see text] were significantly lower when cycling uphill compared to cycling on level ground (P < 0.01). Experiment II revealed that [Formula: see text] was significantly greater for the upright posture than for the dropped posture (P < 0.01) and that the racing position did not affect [Formula: see text]. The main conclusions of this study were that when cycling uphill, it is reasonable to choose (1) a lower cadence and (2) a more upright body position.

Functioning of the Attentional Networks at Rest vs. During Acute Bouts of Aerobic Exercise

The present study explored the effects of three different activity conditions on three attentional functions: alerting, orienting, and executive control. A group of highly experienced cyclists performed the Attention Network Test-Interactions (Callejas, Lupiáñez, & Tudela, 2004) at rest, during moderate aerobic exercise, and during intense aerobic exercise. Results indicated that aerobic exercise accelerated reaction time and reduced the alerting effect compared with the rest condition. However, aerobic exercise did not modulate the functioning of either the orienting or the executive control attentional networks. No differences in reaction time or attentional functioning were observed between the two aerobic exercise workloads. The present results suggest that moderate aerobic exercise modulates the functioning of phasic alertness by increasing the general state of tonic vigilance.

Proximal femoral fracture in a man resulting from modern clipless pedals: a case report

IntroductionThe use of clipless pedals amongst recreational cyclists has become increasingly popular in recent years. We describe a hip fracture, that was sustained due to inadequate set up of such pedals. To the best of our knowledge, this has only been described once before, and this was in the non-English language medical literature.Case ReportA 38-year-old Caucasian man who was a club cyclist sustained a displaced intracapsular fracture of the hip whilst cycling. As a direct result of the incorrect set-up of his clipless pedals he was unable to release his feet whilst slowing to a halt. This resulted in a loss of balance and subsequent fall with a direct impact onto his left hip. The resulting fracture was managed successfully with early closed reduction and fixation. At six month review he was walking unaided without pain but, as yet, has been unable to return to cycling.ConclusionThis case highlights the dangers of clipless pedals even in experienced cyclists, and underlines the importance of proper information for their correct setup to minimise the risk of potentially serious injuries, especially in the region of the hip.

Measuring Changes in Aerodynamic/Rolling Resistances by Cycle-Mounted Power Meters

To develop a protocol for isolating changes in aerodynamic and rolling resistances from field-based measures of power and velocity during level bicycling. We assessed the effect of body position (hands on brake hoods vs drops) and tire pressure changes (414 vs 828 kPa) on aerodynamic and rolling resistances by measuring the power (Pext)-versus-speed (V) relationship using commercially available bicycle-mounted power meters. Measurements were obtained using standard road bicycles in calm wind (<1.0 m·s) conditions at constant velocities (acceleration <0.5 m·s) on a flat 200-m section of a smooth asphalt road. For each experimental condition, experienced road cyclists rode in 50-W increments from 100 to 300 W for women (n=2) or 100 to 400 W for men (n=6). Aerodynamic resistance per velocity squared (k) was calculated as the slope of a linear plot of tractive resistance (RT=power/velocity) versus velocity squared. Rolling resistance (Rr) was calculated as the intercept of this relationship. Aerodynamic resistance per velocity squared (k) was significantly greater (P<0.05) while riding on the brake hoods compared with the drops (mean ± SD: 0.175 ± 0.025 vs 0.155 ± 0.03 N·V). Rolling resistance was significantly greater at 60 psi compared with 120 psi (5.575 ± 0.695 vs 4.215 ± 0.815 N). These results demonstrate that commercially available power meters are sensitive enough to independently detect the changes in aerodynamic and rolling resistances associated with modest changes in body position and substantial changes in tire pressure.

The influence of glove and hand position on pressure over the ulnar nerve during cycling

Background Chronic ulnar nerve compression is believed to be the primary cause of sensory and motor impairments of the hand in cyclists, a condition termed Cyclist's Palsy. The purpose of this study was to quantitatively evaluate the effects that hand position and glove type can have on pressure over the ulnar nerve, specifically in the hypothenar region of the hand. Methods Thirty-six experienced cyclists participated. Subjects rode at a constant cadence and power output on a stationary bicycle with their hands in the tops, drops and hoods of a standard drop handlebar. A high resolution pressure mat was used to record hand pressure with no gloves, unpadded gloves, foam-padded gloves and gel-padded gloves. Wrist posture was simultaneously monitored with a motion capture system. Laser scans of the subject's hand were separately acquired to register pressure maps onto the hand anatomy. Findings Average peak hypothenar pressures of 134–165 kPa were recorded when cyclists did not wear gloves. A drops hand position induced the greatest hypothenar pressure and most extended wrist posture. Padded gloves were able to reduce hypothenar pressure magnitudes by 10 to 28%, with slightly better pressure reduction achieved using thin foam padding. Interpretation The hand pressure magnitudes and loading patterns seen in steady-state cycling are of sufficient magnitude to induce ulnar nerve damage if maintained for long periods. Wearing padded gloves and changing hand position can reduce the magnitude and duration of loading patterns, which are both important to mitigate risk for Cyclist's Palsy during extended rides.

The Effect of Variable Gradients on Pacing in Cycling Time-Trials

It has been reported that performance in cycling time-trials is enhanced when power is varied in response to gradient although such a mechanical pacing strategy has never been confirmed experimentally in the field. The aim of this study was, therefore, to assess the efficacy of mechanical pacing by comparing a constant power strategy of 255 W with a variable power strategy that averaged to 255 W over an undulating time-trial course. 20 experienced cyclists completed 4 trials over a 4 km course with 2 trials at an average constant power of 253 W and 2 trials where power was varied in response to gradient and averaged 260 W. Time normalised to 255 W was 411±31.1 s for the constant power output trials and 399±29.5 s for the variable power output trials. The variable power output strategy therefore reduced completion time by 12±8 s (2.9%) which was significant ( P<0.001). Participants experienced difficulty in applying a constant power strategy over an undulating course which acted to reduce their time gain. It is concluded that a variable power strategy can improve cycling performance in a field time-trial where the gradient is not constant.

Effects of Sprint Interval Training and Body Weight Reduction on Power to Weight Ratio in Experienced Cyclists

The purpose of this study was to determine the effect of supramaximal sprint interval training (SIT), body weight reduction, and a combination of both treatments on peak and average anaerobic power to weight ratio (PPOan:Wt, APOan:Wt) by manipulating peak and average anaerobic power output (PPOan, APOan) and body weight (BW) in experienced cyclists. Participants (N = 34, age = 38.0 +/- 7.1 years) were assigned to 4 groups for a 10-week study. One group performed twice-weekly SIT sessions on a cycle ergometer while maintaining body weight (SIT). A second group did not perform SIT but intentionally reduced body weight (WR). A third group simultaneously performed SIT sessions and reduced body weight (SIT+WR). A control group cycled in their normal routine and maintained body weight (CON). The 30-second Wingate Test assessed pretest and posttest POan:Wt scores. There was a significant mean increase (p < 0.05) from pretest to posttest in PPOan:Wt and APOan:Wt (W x kg(-1)) scores in both SIT (10.82 +/- 1.71 to 11.92 +/- 1.77 and 8.05 +/- 0.64 to 8.77 +/- 0.64, respectively) and WR (10.33 +/- 2.91 to 11.29 +/- 2.80 and 7.04 +/- 1.45 to 7.62 +/- 1.24, respectively). PPOan and APOan (W) increased significantly only in SIT (753.7 +/- 121.0 to 834.3 +/- 150.1 and 561.3 +/- 62.5 to 612.7 +/- 69.0, respectively). Body weight (kg) decreased significantly in WR and SIT + WR (80.3 +/- 13.7 to 75.3 +/- 11.9 and 78.9 +/- 10.8 to 73.4 +/- 10.8, respectively). The results demonstrate that cyclists can use SIT sessions and body weight reduction as singular training interventions to effect significant increases in anaerobic power to weight ratio, which has been correlated to enhanced aerobic cycling performance. However, the treatments were not effective as combined interventions, as there was no significant change in either PPOan:Wt or APOan:Wt in SIT + WR.

Doping use among young elite cyclists: a qualitative psychosociological approach

Using a psychosociological approach, the purpose of this study was to identify and understand the use of doping substances by young elite cyclists. Semi-structured interviews were conducted with young cyclists who were hoping to find a professional team and cyclists who had recently become professional. All of the young cyclists interviewed took nutritional supplements and believed that they improved their performance, which has been shown by other scholars to be a risk factor for doping. These cyclists believed that doping at the professional level in cycling was acceptable but did not approve of it at the amateur level. They were attracted to doping; they were open to using doping substances themselves if it was the key to continuing their cycling career, but only after they became professional. Team staff, doctors, parents and friends helped to create a "clean" environment that prevented the young cyclists from doping before becoming professional. The more experienced cyclists, who doped or used to dope, transmitted the culture of doping to the young cyclists, teaching them doping methods and which substances to use. This study could help to improve prevention and help to detect doping, as it is clear that doping behaviors begin at the amateur level.

Pacing Pattern in a 30-Minute Maximal Cycling Test

The purpose of this study was to investigate the pacing pattern and associated physiological effects in competitive cyclists who performed a 30-minute maximal cycling test. Measurements included oxygen uptake (V O2), heart rate (HR), blood lactate concentration (BLC), rating of perceived exertion (RPE), and work rate in watts. Twelve well-trained amateur cyclists (seven men and five women) whose mean age was 32.4 +/- 8.6 years participated in this study. They performed a 30-minute self-paced maximal cycling test using their own performance road bike attached to a CompuTrainer Pro, which allowed the assessment of work rate (W). During the test, work rate, V O2, and HR were measured every 30 seconds. Subjects' BLC and RPE were obtained every 5 minutes. Results indicate that no significant differences existed across three 10-minute periods for work rate, HR, or V O2. However, RPE at 30 minutes was significantly greater than RPE at 10 and 20 minutes (both p < 0.05). The RPE at 20 minutes was also greater than the RPE at 10 minutes (p < 0.01). Work rate remained relatively constant, with minimal fluctuations occurring throughout the test except for a surge during the final 30 seconds of the test. The associated V O2 was fairly constant over time, whereas HR rose linearly and gradually. It was concluded that pacing in a 30-minute maximal exercise bout performed in the laboratory in experienced cyclists varies minimally until the last 30 seconds. Knowledge of pacing strategy and the linked physiological responses may be helpful to exercise scientists in optimizing performance in the endurance athlete.

Pacing Pattern and Physiological Responses to a 5-Minute Maximal Exercise Bout

The purpose of this study was to describe the pacing strategy of experienced cyclists in a 5-minute maximal exercise bout and to describe selected physiological responses associated with this effort. Six experienced and well-trained competitive cyclists (five males, one female) with a mean (+/-SD) age, height, and mass of 27.0 +/- 4.77 years, 174.7 +/- 8.57 cm, and 71.0 +/- 6.45 kg, performed a 5-minute maximal exercise bout in a laboratory on a racing cycle. Subjects were free to determine their work rate throughout. During exercise, data were collected for work rate, heart rate (HR), [latin capital V with dot above]O2, electromyography of the rectus femoris and vastus lateralis, oxygen saturation, and rating of perceived exertion. All six subjects selected a pacing strategy characterized by a surge in work rate in the first minute followed by a gradual decline until the last minute, when a sprint to the end occurred. Values for HR, respiratory exchange ratio, and blood lactate concentration (182.8 +/- 2.8 bpm, 1.08 +/- 0.07, and 15.5 +/- 2.1 mmol x L-1, respectively) indicated that [latin capital V with dot above]O2 (3.6 +/- 0.4 L x min-1) was close to or at maximum from minutes 2 to 5. Oxygen saturation dropped continuously across time, reaching <94% in the last minute, and rating of perceived exertion was 19.5 +/- 0.8. Electromyographic activity of the rectus femoris and vastus lateralis was not significantly related to work rate during the bout (p > 0.05). It is concluded that work rate or pace is uneven in an all-out, 5-minute exercise bout in experienced cyclists, yet the physiological responses are near maximal in minutes 2-5. Cyclists seem to pace themselves in a common pattern in short-term stochastic exercise bouts. The possible benefits of including some stochastic exercise in the training programs of athletes might be worthy of examination.

Interindividual variability of electromyographic patterns and pedal force profiles in trained cyclists

The aim of this study was to determine whether high inter-individual variability of the electromyographic (EMG) patterns during pedaling is accompanied by variability in the pedal force application patterns. Eleven male experienced cyclists were tested at two submaximal power outputs (150 and 250 W). Pedal force components (effective and total forces) and index of mechanical effectiveness were measured continuously using instrumented pedals and were synchronized with surface electromyography signals measured in ten lower limb muscles. The intersubject variability of EMG and mechanical patterns was assessed using standard deviation, mean deviation, variance ratio and coefficient of cross-correlation (_R(0), with lag time = 0). The results demonstrated a high intersubject variability of EMG patterns at both exercise intensities for biarticular muscles as a whole (and especially for Gastrocnemius lateralis and Rectus femoris) and for one monoarticular muscle (Tibialis anterior). However, this heterogeneity of EMG patterns is not accompanied by a so high intersubject variability in pedal force application patterns. A very low variability in the three mechanical profiles (effective force, total force and index of mechanical effectiveness) was obtained in the propulsive downstroke phase, although a greater variability in these mechanical patterns was found during upstroke and around the top dead center, and at 250 W when compared to 150 W. Overall, these results provide additional evidence for redundancy in the neuromuscular system.

Proposta metodológica para a avaliação da técnica da pedalada de ciclistas: estudo de caso

No estudo da biomecânica do ciclismo diversas técnicas têm sido utilizadas para descrever e compreender o movimento da pedalada. O objetivo deste estudo é propor uma metodologia para a avaliação de ciclistas sob o ponto de vista das forças aplicadas no pedal. Um ciclista de elite foi avaliado por meio de um protocolo que consistiu em alterar o selim em quatro diferentes posições (deslocado para cima, para baixo, para frente e para trás) a partir da posição de referência, especificamente, aquela adotada para treinamento pelo ciclista. A mudança no ajuste do selim foi de 1 cm. A bicicleta do atleta foi acoplada a um ciclossimulador magnético. A carga do teste foi normalizada por um critério fisiológico (segundo limiar ventilatório), simulando o ritmo de prova do atleta. O pedal direito foi substituído por um pedal bidimensional instrumentado para registrar as forças normal e tangencial. A média do impulso angular da força efetiva foi calculada a partir de dez ciclos consecutivos de pedalada. As mudanças na posição do selim modificaram o impulso da força efetiva em relação à posição de referência. Sendo assim, o protocolo é eficaz e pode ser aplicado em diferentes situações.

Comparisons of Models of Cognitive Strategies During a Cycling Maximal Test and Simulated Time Trial

PURPOSE: Test the effort-related attention model and cognitive strategy classifcation scheme in a maximal and time trial cycle task. METHODS: Eight cyclists (5 M and 3 W, 32.38±1.66 yrs.) performed a maximal cycling trial at 70 rpm with an increase of 210 kilopond meters/min every 2 minutes until exhaustion (peak VO2 = 48.79± 3.29) on a Monark 812e cycle ergometer. Cognitive strategy, OMNI-RPE, minute VO2, and HR were sampled every two minutes to exhaustion. Next, a simulated time trial on rollers, with power meters was performed in 2 groups of 4 cyclists. Cognitive strategies, OMNI-RPE, and HR were sampled every 5 minutes for the 30 minute. Regression analyses and qualitative analyses were performed to analyze the data. RESULTS: The regression analyses revealed significant attention narrowing to association with increases in RPE and HR while cognitive strategies demonstrated an inverse relation with time. The model accounted for a significant amount of variance in both maximal and time trial (r2's = 0.55 and 0.72, p's<0.001). Interview data revealed that non-experienced cyclists dealt with discomfort of cycling differently. Additionally, the experienced cyclists demonstrated cognitive strategy changes at similar relative time points (variance of 3%) compared to non-experienced cyclists (variance of 24%) across trials. CONCLUSIONS: The effort-related attention model was supported as RPE and HR increased across time/intensity and attention narrowed to association. Also, experienced cyclists appeared to use situation management to consistently applying cognitive strategies. Future research should seek to study cognitive strategies in a larger sample.Table: Correlation Coefficients

Reliability of Sprint Test Indices in Well-Trained Cyclists

The study aim was to assess reliability of repeated laboratory sprint tests in well-trained endurance cyclists. Eleven male cyclists (mean +/- standard deviation: 27 +/- 6 yr, 1.79 +/- 0.04 m, 70.1 +/- 3.3 kg) performed a maximal 30-second sprint test on four separate occasions using their own bicycle fitted with an SRM powermeter on a Kingcycle air-braked ergometer. Peak power output (W (peak)), mean power (W (mean)) and an index of fatigue (FI) were calculated. Three minutes post sprint, capillarised blood lactate measurements were taken and analysed. No significant differences (p > 0.05) were found between trials for W (peak), W (mean), FI and blood lactate concentration. Repeatability of W (peak), W (mean), and fatigue index improved across trials 2 and 3 when compared to trials 1 and 2. The highest CV for these variables was recorded between trials 3 and 4. The CV for W (peak) was 4.5 +/- 1.6 %, W (mean) 2.4 +/- 1.2 %, and FI 17.2 +/- 7.1 %. Intraclass reliability coefficients were 0.93 (95 % CI 0.84 - 0.98), 0.94 (95 % CI 0.86 - 0.98) and 0.89 (95 % CI 0.69 - 0.95) respectively. Blood lactate concentration ranged between 5.35 and 14.52 mmol.l(-1), with a mean CV of 12.1 +/- 4.2 %. The CV for trials 2 and 3 revealed the highest CV for blood lactate concentration (15.1 %). The lowest CV for this variable (10.2 %) was recorded between trials 3 and 4. The intraclass reliability coefficient for blood lactate concentration was 0.79 (95 % CI 0.58 - 0.93). The results of this study indicate that there is no improvement in the reliability of sprint test indices when assessing well-trained, experienced cyclists, riding on their own cycle equipment.

Pacing Strategies And Physiological Responses To A 5 Min Maximal Cycle Bout

Purpose To describe the pacing strategy of experienced cyclists in a 5 min maximal exercise bout and to examine the relationships between selected physiological, electromyographical, and perceptual responses associated with this effort. Methods Six experienced and well-trained competitive cyclists (five males, one female) with a mean (± SD) age, height, and mass of 27.0 ± 4.8 yr, 174.7 ± 8.6 cm, and 71.0 ± 6.5 kg, performed a 5 min maximal exercise bout in a laboratory on a racing cycle which was mounted to a device measuring work rate. Subjects were instructed to work as hard as possible during the bout and were free to determine their work rate throughout. During the exercise bout data were collected for work rate (W), heart rate (HR), oxygen consumption (VO2), electromyography (EMG) of the rectus femoris (RF) and vastus lateralis (VL). Blood lactate concentration (BLC) was assessed 1, 3, and 5-min post-exercise. A repeated-measures ANOVA was used to compare work rate over time with Scheffe post-hoc analysis for the determination of individual differences (p < .05). Pearson correlations were utilized to describe relationships among selected variables. Results Work rate averaged over 30 sec time periods of the 5 min test changed significantly (p < .05). All six subjects selected a pacing strategy characterized by a surge in work rate in the first 30 sec followed by a gradual but significant decline in min 1 to 4 until the last min where a sprint to the end occurred (Figure). HR, respiratory exchange ratio, and post-exercise BLC (182 ± 3 bpm, 1.08 ± 0.07, and 15.5 ± 2.1 mmol/L) indicated that VO2 (3.6 ± 0.4 L/min) was close to or at maximum from min 2–5. EMG activity of the RF and VL was not significantly related to work rate (r = −.54 and .47, p > .05).FigureConclusion It is concluded that pacing strategy is stochastic in an all-out 5 min exercise bout in experienced cyclists yet the physiological responses are near maximum in min 2–5.

Pacing Strategies And Physiological Responses To A 5 Min Maximal Cycle Bout

Purpose To describe the pacing strategy of experienced cyclists in a 5 min maximal exercise bout and to examine the relationships between selected physiological, electromyographical, and perceptual responses associated with this effort. Methods Six experienced and well-trained competitive cyclists (five males, one female) with a mean (± SD) age, height, and mass of 27.0 ± 4.8 yr, 174.7 ± 8.6 cm, and 71.0 ± 6.5 kg, performed a 5 min maximal exercise bout in a laboratory on a racing cycle which was mounted to a device measuring work rate. Subjects were instructed to work as hard as possible during the bout and were free to determine their work rate throughout. During the exercise bout data were collected for work rate (W), heart rate (HR), oxygen consumption (VO2), electromyography (EMG) of the rectus femoris (RF) and vastus lateralis (VL). Blood lactate concentration (BLC) was assessed 1, 3, and 5-min post-exercise. A repeated-measures ANOVA was used to compare work rate over time with Scheffe post-hoc analysis for the determination of individual differences (p < .05). Pearson correlations were utilized to describe relationships among selected variables. Results Work rate averaged over 30 sec time periods of the 5 min test changed significantly (p < .05). All six subjects selected a pacing strategy characterized by a surge in work rate in the first 30 sec followed by a gradual but significant decline in min 1 to 4 until the last min where a sprint to the end occurred (Figure). HR, respiratory exchange ratio, and post-exercise BLC (182 ± 3 bpm, 1.08 ± 0.07, and 15.5 ± 2.1 mmol/L) indicated that VO2 (3.6 ± 0.4 L/min) was close to or at maximum from min 2–5. EMG activity of the RF and VL was not significantly related to work rate (r = −.54 and .47, p > .05).FigureConclusion It is concluded that pacing strategy is stochastic in an all-out 5 min exercise bout in experienced cyclists yet the physiological responses are near maximum in min 2–5.

Effect Of Segmental Growth On The Force Construction Of Pedaling As A Function Of Speed

Motor skill acquisition is characterized by improvements in the application of taskappropriate forces. Muscular and non-muscular forces act in concert to produce a resultant force that complies with the goal of the task. Non-muscular forces are directly dependent on the anthropometry of the performer. If the resultant force to be produced is the same between performers, inter-participant differences in anthropometry might require muscular adjustments to changing non-muscular forces. This effect might depend on movement speed as it also influences non-muscular forces. Differences in the application of muscular forces may therefore represent functional adjustments needed to account for changes in anthropometry. Such adjustments could pose confounds if age-related differences in muscular forces are to be attributed to features of the neuro-motor system. PURPOSE The purposes of this study were to determine (a) the effect of age-related changes in anthropometry on the application of muscular forces and (b) how this effect depends on movement speed. METHODS A torque-driven biomechanical model of two-legged pedaling was developed. The model tracked experimental kinematics and forces obtained from an experienced adult cyclist who signed informed consent before participating. The anthropometrics of the model were modified according to Jensen (1989). Segmental mass proportions, center of mass locations, and radii of gyration were scaled to children's dimensions (5, 7.5, and 10 years of age). Pedaling at 60 rpm and 120 rpm at a moderate resistance was simulated. The forces to be produced were scaled in proportion to body mass, and the kinematics were held constant across all simulations. This procedure enabled us to isolate the effect of differences in anthropometry on muscular force application. The muscular contribution to crank power was compared across age groups using ANOVAs (alpha=.05) and effect sizes (ES). RESULTS Relative changes in anthropometry between 5 and 10 years of age did not significantly influence muscular power production neither at 60 rpm nor at 120 rpm (p>.05). In addition, the effect sizes quantifying differences between age groups were small (mean ES=0.16). CONCLUSIONS The results demonstrate that during pedaling at a moderate resistance, changing anthropometry during childhood does not influence the force construction in pedaling over a broad range of movement speeds. It can therefore be concluded that during pedaling at these cadences, age-related differences in muscular force application can be attributed to features of the neuro-motor system. Supported by the National Science Foundation under Grant 9986221

Effect Of Segmental Growth On The Force Construction Of Pedaling As A Function Of Speed

Motor skill acquisition is characterized by improvements in the application of taskappropriate forces. Muscular and non-muscular forces act in concert to produce a resultant force that complies with the goal of the task. Non-muscular forces are directly dependent on the anthropometry of the performer. If the resultant force to be produced is the same between performers, inter-participant differences in anthropometry might require muscular adjustments to changing non-muscular forces. This effect might depend on movement speed as it also influences non-muscular forces. Differences in the application of muscular forces may therefore represent functional adjustments needed to account for changes in anthropometry. Such adjustments could pose confounds if age-related differences in muscular forces are to be attributed to features of the neuro-motor system. PURPOSE The purposes of this study were to determine (a) the effect of age-related changes in anthropometry on the application of muscular forces and (b) how this effect depends on movement speed. METHODS A torque-driven biomechanical model of two-legged pedaling was developed. The model tracked experimental kinematics and forces obtained from an experienced adult cyclist who signed informed consent before participating. The anthropometrics of the model were modified according to Jensen (1989). Segmental mass proportions, center of mass locations, and radii of gyration were scaled to children's dimensions (5, 7.5, and 10 years of age). Pedaling at 60 rpm and 120 rpm at a moderate resistance was simulated. The forces to be produced were scaled in proportion to body mass, and the kinematics were held constant across all simulations. This procedure enabled us to isolate the effect of differences in anthropometry on muscular force application. The muscular contribution to crank power was compared across age groups using ANOVAs (alpha=.05) and effect sizes (ES). RESULTS Relative changes in anthropometry between 5 and 10 years of age did not significantly influence muscular power production neither at 60 rpm nor at 120 rpm (p>.05). In addition, the effect sizes quantifying differences between age groups were small (mean ES=0.16). CONCLUSIONS The results demonstrate that during pedaling at a moderate resistance, changing anthropometry during childhood does not influence the force construction in pedaling over a broad range of movement speeds. It can therefore be concluded that during pedaling at these cadences, age-related differences in muscular force application can be attributed to features of the neuro-motor system. Supported by the National Science Foundation under Grant 9986221

Lactate Steady State During 20km Simulated Cycle Racing

The purposes of this study were to determine if experienced cyclists self-select lactate steady state (LSS) during a simulated 20km time trial (TT) and if the attainment of LSS was associated with consistent pacing. Twelve experienced cyclists performed the TT on a computerized trainer system. Compared to values at 7.5km, lactate was significantly lower at 17.5km, and PO was reduced at 15 and 17.5km. Variability in lactate and variability in power output, as measured by intrasubject standard deviation, were highly correlated (r = 0.75, p <0.01) from 5km onward. Only 2 of 12 subjects met the previously published criteria for LSS (< 1.0mmol·L−1 change during exercise), and these subjects had the lowest variability in power output. Self-selection of a consistent pace was associated with the attainment of LSS; however, the majority of experienced cyclists did not self-select lactate steady state during a 20km simulated cycle race.