One previous study even suggested that for gradients higher than 7.2%, the impact of speed, and therefore of air resistance, on energy expenditure can be neglected. 4 If the impact of drafting effect on uphill cycling performance has never been studied yet, these results suggest that the presence of
Theo Ouvrard, Alain Groslambert, Gilles Ravier, Sidney Grosprêtre, Philippe Gimenez and Frederic Grappe
Alfred Nimmerichter, Bernhard Prinz, Kevin Haselsberger, Nina Novak, Dieter Simon and James G. Hopker
While a number of studies have investigated gross efficiency (GE) in laboratory conditions, few studies have analyzed it in field conditions. Therefore, the aim of this study was to analyze the effect of gradient and cadence on GE in field conditions.
Thirteen trained cyclists (mean ± SD age 23.3 ± 4.1 y, stature 177.0 ± 5.5 cm, body mass 69.0 ± 7.2 kg, maximal oxygen uptake [V̇O2max] 68.4 ± 5.1 mL ∙ min–1 ∙ kg–1) completed an incremental graded exercise test to determine ventilatory threshold (VT) and 4 field trials of 6 min duration at 90% of VT on flat (1.1%) and uphill terrain (5.1%) with 2 different cadences (60 and 90 rpm). V̇O2 was measured with a portable gas analyzer and power output was controlled with a mobile power crank that was mounted on a 26-in mountain bike.
GE was significantly affected by cadence (20.6% ± 1.7% vs 18.1% ± 1.3% at 60 and 90 rpm, respectively; P < .001) and terrain (20.0% ± 1.5% vs 18.7% ± 1.7% at flat and uphill cycling, respectively; P = .029). The end-exercise V̇O2 was 2536 ± 352 and 2594 ± 329 mL/min for flat and uphill cycling, respectively (P = .489). There was a significant difference in end-exercise V̇O2 between 60 (2352 ± 193 mL/min) and 90 rpm (2778 ± 431 mL/min) (P < .001).
These findings support previous laboratory-based studies demonstrating reductions in GE with increasing cadence and gradient that might be attributed to changes in muscle-activity pattern.
Graham E. Caldwell, James M. Hagberg, Steve D. McCole and Li Li
Lower extremity joint moments were investigated in three cycling conditions: level seated, uphill seated and uphill standing. Based on a previous study (Caldwell, Li, McCole, & Hagberg, 1998), it was hypothesized that joint moments in the uphill standing condition would be altered in both magnitude and pattern. Eight national caliber cyclists were filmed while riding their own bicycles mounted to a computerized ergometer. Applied forces were measured with an instrumented pedal, and inverse dynamics were used to calculate joint moments. In the uphill seated condition the joint moments were similar in profile to the level seated but with a modest increase in magnitude. In the uphill standing condition the peak ankle plantarflexor moment was much larger and occurred later in the downstroke than in the seated conditions. The extensor knee moment that marked the first portion of the down-stroke for the seated trials was extended much further into the downstroke while standing, and the subsequent knee flexor moment period was of lower magnitude and shorter duration. These moment changes in the standing condition can be explained by a combination of more forward hip and knee positions, increased magnitude of pedal force, and an altered pedal force vector direction. The data support the notion of an altered contribution of both muscular and non-muscular sources to the applied pedal force. Muscle length estimates and muscle activity data from an earlier study (Li & Caldwell, 1996) support the unique roles of mono-articular muscles for energy generation and bi-articular muscles for balancing of adjacent joint moments in the control of pedal force vector direction.
Graham E. Caldwell, Li Li, Steve D. McCole and James M. Hagberg
Alterations in kinetic patterns of pedal force and crank torque due to changes in surface grade (level vs. 8% uphill) and posture (seated vs. standing) were investigated during cycling on a computerized ergometer. Kinematic data from a planar cine analysis and force data from a pedal instrumented with piezoelectric crystals were recorded from multiple trials of 8 elite cyclists. These measures were used to calculate pedal force, pedal orientation, and crank torque profiles as a function of crank angle in three conditions: seated level, seated uphill, and standing uphill. The change in surface grade from level to 8% uphill resulted in a shift in pedal angle (toe up) and a moderately higher peak crank torque, due at least in part to a reduction in the cycling cadence. However, the overall patterns of pedal and crank kinetics were similar in the two seated conditions. In contrast, the alteration in posture from sitting to standing on the hill permitted the subjects to produce different patterns of pedal and crank kinetics, characterized by significantly higher peak pedal force and crank torque that occurred much later in the downstroke. These kinetic changes were associated with modified pedal orientation (toe down) throughout the crank cycle. Further, the kinetic changes were linked to altered nonmuscular (gravitational and inertial) contributions to the applied pedal force, caused by the removal of the saddle as a base of support.
Marco Arkesteijn, Simon Jobson, James Hopker and Louis Passfield
Previous research has shown that cycling in a standing position reduces cycling economy compared with seated cycling. It is unknown whether the cycling intensity moderates the reduction in cycling economy while standing.
The aim was to determine whether the negative effect of standing on cycling economy would be decreased at a higher intensity.
Ten cyclists cycled in 8 different conditions. Each condition was either at an intensity of 50% or 70% of maximal aerobic power at a gradient of 4% or 8% and in the seated or standing cycling position. Cycling economy and muscle activation level of 8 leg muscles were recorded.
There was an interaction between cycling intensity and position for cycling economy (P = .03), the overall activation of the leg muscles (P = .02), and the activation of the lower leg muscles (P = .05). The interaction showed decreased cycling economy when standing compared with seated cycling, but the difference was reduced at higher intensity. The overall activation of the leg muscles and the lower leg muscles, respectively, increased and decreased, but the differences between standing and seated cycling were reduced at higher intensity.
Cycling economy was lower during standing cycling than seated cycling, but the difference in economy diminishes when cycling intensity increases. Activation of the lower leg muscles did not explain the lower cycling economy while standing. The increased overall activation, therefore, suggests that increased activation of the upper leg muscles explains part of the lower cycling economy while standing.
William M. Bertucci, Andrew C. Betik, Sebastien Duc and Frederic Grappe
This study was designed to examine the biomechanical and physiological responses between cycling on the Axiom stationary ergometer (Axiom, Elite, Fontaniva, Italy) vs. field conditions for both uphill and level ground cycling. Nine cyclists performed cycling bouts in the laboratory on an Axiom stationary ergometer and on their personal road bikes in actual road cycling conditions in the field with three pedaling cadences during uphill and level cycling. Gross efficiency and cycling economy were lower (–10%) for the Axiom stationary ergometer compared with the field. The preferred pedaling cadence was higher for the Axiom stationary ergometer conditions compared with the field conditions only for uphill cycling. Our data suggests that simulated cycling using the Axiom stationary ergometer differs from actual cycling in the field. These results should be taken into account notably for improving the precision of the model of cycling performance, and when it is necessary to compare two cycling test conditions (field/laboratory, using different ergometers).
Grégoire P. Millet, Cyrille Tronche and Frédéric Grappe
To use measurement by cycling power meters (Pmes) to evaluate the accuracy of commonly used models for estimating uphill cycling power (Pest). Experiments were designed to explore the influence of wind speed and steepness of climb on accuracy of Pest. The authors hypothesized that the random error in Pest would be largely influenced by the windy conditions, the bias would be diminished in steeper climbs, and windy conditions would induce larger bias in Pest.
Sixteen well-trained cyclists performed 15 uphill-cycling trials (range: length 1.3–6.3 km, slope 4.4–10.7%) in a random order. Trials included different riding position in a group (lead or follow) and different wind speeds. Pmes was quantified using a power meter, and Pest was calculated with a methodology used by journalists reporting on the Tour de France.
Overall, the difference between Pmes and Pest was –0.95% (95%CI: –10.4%, +8.5%) for all trials and 0.24% (–6.1%, +6.6%) in conditions without wind (>2 m/s). The relationship between percent slope and the error between Pest and Pmes were considered trivial.
Aerodynamic drag (affected by wind velocity and orientation, frontal area, drafting, and speed) is the most confounding factor. The mean estimated values are close to the power-output values measured by power meters, but the random error is between ±6% and ±10%. Moreover, at the power outputs (>400 W) produced by professional riders, this error is likely to be higher. This observation calls into question the validity of releasing individual values without reporting the range of random errors.
Umberto Emanuele, Tamara Horn and Jachen Denoth
The main aim of this study was to compare the freely chosen cadence (FCC) and the cadence at which the blood lactate concentration at constant power output is minimized (optimal cadence [Copt]). The second aim was to examine the effect of a concomitant change of road incline and body position on FCC, the maximal external power output (Pmax), and the corresponding Copt.
FCC, Copt, and Pmax were analyzed under 2 conditions: cycling on level ground in a dropped position (LGDP) and cycling uphill in an upright position (UHUP). Seven experienced cyclists participated in this study. They cycled on a treadmill to test the 2 main hypotheses: Experienced cyclists would choose an adequate cadence close to Copt independent of the cycling condition, and FCC and Copt would be lower and Pmax higher for UHUP than with LGDP.
Most but not all experienced cyclists chose an adequate cadence close to Copt. Independent of the cycling condition, FCC and Copt were not statistically different. FCC (82.1 ± 11.1 and 89.3 ± 10.6 rpm, respectively) and Copt (81.5 ± 9.8 and 87.7 ± 10.9 rpm, respectively) were significantly lower and Pmax was significantly higher (2.0 ± 2.1%) for UHUP than for LGDP.
Most experienced cyclists choose a cadence near Copt to minimize peripheral fatigue at a given power output independent of the cycling condition. Furthermore, it is advantageous to use a lower cadence and a more upright body position during uphill cycling.
Original Research Pedal and Crank Kinetics in Uphill Cycling Graham E. Caldwell * Li Li * Steve D. McCole * James M. Hagberg * 8 1998 14 3 245 259 10.1123/jab.14.3.245 Research A Comparison of the Kinetic and Kinematic Characteristics of Plyometric Drop-Jump and Pendulum Exercises Neil E
* David G. Kerwin * 5 1999 15 2 152 165 10.1123/jab.15.2.152 Lower Extremity Joint Moments during Uphill Cycling Graham E. Caldwell * James M. Hagberg * Steve D. McCole * Li Li * 5 1999 15 2 166 181 10.1123/jab.15.2.166 Original Research Determining the Force-Length-Velocity Relations of the