Optimal Pedaling Research Articles

Effects of Desk Pedaling Work Rate on Concurrent Work Performance among Physically Inactive Adults: A Randomized Experiment.

Under-desk pedaling devices could help reduce health risks associated with the global decline in work-related energy expenditure. However, the optimal pedaling work rate to facilitate concurrent work performance among physically inactive adults is unclear. We examined the effects of two light-intensity pedaling work rates on physically inactive adults' work performance. We recruited equal numbers of older (45-65 yr) versus younger (20-44 yr), male versus female, and overweight/obese (body mass index [BMI], 25-35 kg·m -2 ) versus normal weight (BMI, 18.5-24.9 kg·m -2 ) participants. Using a Graeco-Latin square design, participants ( n = 96) completed a laboratory experiment to evaluate the effects of using an under-desk pedaling device at two seated light-intensity work rates (17 and 25 W), relative to a seated nonpedaling condition on objectively measured typing, reading, logical reasoning, and phone task performance. Ergonomic comfort under each pedaling work rate was also assessed. Equivalence tests were used to compare work performance under the pedaling versus nonpedaling conditions. Treatment fidelity to the 17- and 25-W pedaling work rates exceeded 95%. Mean work performance scores for each pedaling and nonpedaling condition were equivalent under alpha = 0.025. Age, sex, and BMI did not significantly moderate the effect of pedaling on work performance. Participants reported greater ergonomic comfort while completing work tasks at the 17-W relative to the 25-W work rate. Physically inactive adults obtained similar work performance scores under the 17- and 25-W pedaling and the nonpedaling conditions, suggesting that either pedaling work rate could help reduce health risks of sedentary work time. The 17-W work rate yielded greater ergonomic comfort and may be an appropriate starting point for introducing diverse inactive workers to under-desk pedaling.

Analysis of elite road-cycling sprints in relation to maximal power-velocity-endurance profile: a longitudinal one-case study.

The aims of the present study were to characterize the mechanical output of final road sprints of an elite sprinter during international competitions in relation to his power-velocity-endurance characteristics and to investigate the relationship between this sprint performance and the power produced during preceding phases of the race. The sprinter performed a set of short and long sprints (5 to 15-s) on a cycle ergometer to determine his maximal power-velocity-endurance profile. Based on eleven races, the distribution of power throughout each race, peak and mean power (Ppeak and Pmean ) and associated pedaling rates (vPpeak and vPmean ) during the final sprint were analyzed. The power-velocity-endurance profile of the sprinter indicated that his theoeretical mean maximal power and corresponding optimal pedaling rate ranged from 20.0W.kg-1 (124rpm) for a 1-s sprint to 15.0W.kg-1 (109rpm) for 20s. Race data showed that final road sprints were mainly performed on the ascending limb of the power-velocity relationship (vPpeak , 104±8and vPmean , 101±8rpm). Additionally, Ppeak and Pmean were lower than the theoretical maximal power determined from the power-velocity-endurance profile (9.9±7.0% and 10.6±9.8%, respectively), which highlighted a significant state of fatigue induced by the race. Finally, sprint power exhibited a high variability between races and was strongly related to the level of power produced during the last minute before the sprint. These findings show the importance of considering both the power-velocity-endurance qualities and the power demand of the last lead-up phase before the sprint in order to optimize final sprint performance.

Generation of optimal pedaling motion by forward dynamics simulation using Musculoskeletal Model

Generation of optimal pedaling motion by forward dynamics simulation using Musculoskeletal Model

Effects of Bicycle Crank Length on Gross Efficiency, Power, and Joint Kinematics During Cycling Ergometry

PURPOSE: To determine the effects of six different crank lengths (150, 165, 170, 172.5, 175, and 180 mm) on gross efficiency, maximum power, optimal pedaling rate (cadence at maximum power), and joint kinematics of the hip and knee. METHODS: Elite level cyclists (n = 18) participated in two visits to the Cal Poly Cycling Lab. The purpose of the first lab session was to measure VO2 peak (60.6 ± 7.6 mL·min-1·kg-1), participant characteristics (28.2 ± 5.3 yrs; 175.6 ± 7.4 cm; 70.5 ± 5.3 kg; 255 ± 105 km/week), and complete familiarization trials with four different crank lengths. These practice trials consisted of 4 second seated maximal sprints on the participant’s original crank length (170, 172.5, or 175 mm) and three other crank lengths (150, 165, and 180 mm). The second test session was a single-blind randomized crossover design with the six different crank lengths. After a 5 minute warm up, participants performed a 3 minute steady state effort at 65% VO2 peak and 90 rpm. This was followed by two maximum effort 4 second seated sprints with 90 seconds rest prior to each sprint. Participants rested for 5 minutes before the next crank length trial. RESULTS: During steady state cycling, shorter cranks had a higher gross efficiency (150 mm: 22.1%) compared to longer cranks (180 mm: 21.6%), (p < 0.001). No significant differences were found between crank lengths for maximum power output during the 4 second sprints. There was an increase in optimal pedaling rate between 150 mm cranks (130 rpm) and all other lengths (180 mm: 120 rpm) (p < 0.001). 150 mm cranks have a significantly smaller hip (45°) and knee (67°) range of motion than all other cranks measured (180 mm: hip 51°, knee 75°) (p < 0.001). CONCLUSIONS: Shorter cranks resulted in a significantly higher gross efficiency, smaller knee and hip range of motion, and a higher optimal pedaling rate.

Noncircular Chainrings Do Not Influence Maximum Cycling Power.

Noncircular chainrings could increase cycling power by prolonging the powerful leg extension/flexion phases, and curtailing the low-power transition phases. We compared maximal cycling power-pedaling rate relationships, and joint-specific kinematics and powers across 3 chainring eccentricities (CON = 1.0; LOWecc = 1.13; HIGHecc = 1.24). Part I: Thirteen cyclists performed maximal inertial-load cycling under 3 chainring conditions. Maximum cycling power and optimal pedaling rate were determined. Part II: Ten cyclists performed maximal isokinetic cycling (120rpm) under the same 3 chainring conditions. Pedal and joint-specific powers were determined using pedal forces and limb kinematics. Neither maximal cycling power nor optimal pedaling rate differed across chainring conditions (all p > .05). Peak ankle angular velocity for HIGHecc was less than CON (p < .05), while knee and hip angular velocities were unaffected. Self-selected ankle joint-center trajectory was more eccentric than HIGHecc with an opposite orientation that increased velocity during extension/flexion and reduced velocity during transitions. Joint-specific powers did not differ across chainring conditions, with a small increase in power absorbed during ankle dorsiflexion with HIGHecc. Multiple degrees of freedom in the leg, crank, and pedal system allowed cyclists to manipulate ankle angular velocity to maintain their preferred knee and hip actions, suggesting maximizing extension/flexion and minimizing transition phases may be counterproductive for maximal power.

Kinematic Measures Of The Knee While Cycling

Factors contributing to knee pain in cyclists include deviations from optimal pedaling patterns and poor bike fit. Accurate measurement of kinematics is essential to obtain optimal positioning, but motion analysis equipment cost is an obstacle for many clinicians. PURPOSE: To compare the Retül 3D motion capture system to the Vicon 3D system. A lack of significant difference between devices would support a low-cost option for clinicians working with cyclists. METHODS: Cycling kinematics were captured from eleven competitive female cyclists using a 10-camera Vicon MX system and compared with a cycling-specific motion analysis system, Retül, while pedaling at 70% peak power output on a Velotron cycle ergometer. RESULTS: MANOVA demonstrated no significant difference between systems for knee range of motion (ROM) (mean difference (MD)=0.12°, p=0.96), knee extension (MD=0.12°, p=0.10), knee frontal plane knee angles (MD=2.7°, p=0.15), ankle dorsiflexion (DF) (MD=1.45°, p=0.46) and plantarflexion (PF) (MD=4.51°). However, knee flexion (MD=1.42°, p=0.02), hip flexion (MD=32.83°, p<0.001), hip ROM (MD=3.8°, p<0.001), ankle ROM (MD=3.7°, p<0.001) and measurement of the mean knee distance from bicycle centerline (MD=11.13 mm, p<0.001) were significantly different between systems. ICC indicated moderate agreement between systems for knee flexion (ICC(2,5)=0.52, p<0.001). Linear regression of difference scores on mean scores demonstrate a significant relationship for knee flexion, hip ROM and ankle DF (p=0.66, p=0.10, p=0.38, respectively). CONCLUSION: In general, these data support Retül for use in comparison with Vicon for the measurement of knee extension, ankle DF and ankle PF, which are most relevant measurements for obtaining correct fit on a bicycle. Keywords: Bike-fit, kinematics, agreement

Increase in Maximal Cycling Power With Acute Dietary Nitrate Supplementation.

This study determined whether NO3- supplementation could acutely enhance maximal power in trained athletes. In this double-blind, crossover study, 13 trained athletes performed maximal inertial-load cycling trials (3-4 s) immediately before (PRE) and after (POST) consuming either NO3-rich (NO3) or NO3-depleted (PLA) BRJ to assess acute changes (ie, within the same day) in maximal power (PMAX) and optimal pedaling rate (RPMopt). Participants also performed maximal isokinetic cycling (30 s) to assess performance differences after supplementation. 2 x 2 repeated-measures ANOVA indicated a greater increase in PMAX from PRE to POST NO3 (PRE 1160 ± 301 W to POST 1229 ± 317 W) than with PLA (PRE 1191 ± 298 W to POST 1213 ± 300 W) (P = .009; ηp2 = 0.45). A paired t-test verified a greater relative change in PMAX after NO3 (6.0% ± 2.6%) than with PLA (2.0% ± 3.8%) (P = .014; d = 1.21). RPMopt remained unchanged from PRE (123 ± 14 rpm) to POST PLA (122 ± 14 rpm) but increased from PRE (120 ± 14 rpm) to POST NO3 (127 ± 13 rpm) (P = .043; ηp2 = 0.30). There was no relative change in RPMopt after PLA (-0.3% ± 4.1%), but there was an increase after NO3 (6.5% ± 11.4%) (P = .049; d = 0.79). No differences were observed between the 30-s isokinetic trials. Acute NO3- supplementation can enhance maximal muscle power in trained athletes. These findings may particularly benefit power-sport athletes who perform brief explosive actions.

The Body & the Bike: A Kinetic Chain analysis of Cycling Overuse Injury

Introduction : Physiotherapists, osteopaths, doctors, bike-fitters and other cycling injury managers, are perfectly placed to help the ever-growing cycling community to become better riders as well as to prevent pain and injury. Whilst there are a myriad of “bike set-up” protocols available, some more evidence based than others, very few “bike set-up” practitioners take into account the body and its complex neuromuscular and kinematic abilities. There is no argument that understanding the geometry around optimal configuration is an important component for efficiency and injury prevention (Wisbey-Roth 2009), and some leading “Bike-Fit” proponents argue the neuromuscular perspective (Steve Hogg 2007). There are also endless references to optimal pedalling technique- “spinning the pedals”, “elegant”, “wipe the mud of the shoe”, “like a duck swimming” or “smooth and continuous”(Colson from Brukner and Khan 2012), implying that optimising activation patterns has a distinct role in good pedaling technique. Overuse injuries make up a large portion of injuries in aerobic sports that require long training sessions with a monotonous routine eg, long-distance running, bicycling or cross-country skiing (Bahr 2009). The greatest prevalence in overuse injuries in cycling is at the lumbar spine and knee, and efforts to prevent overuse injury should focus on these areas (Clarsen 2010). Maintaining or restoring precise movement of specific segments is the key to preventing or correcting musculoskeletal pain (Sahrmann 2002), and cycling injury management providers are clinically the best placed to be precise in the assessment and management of the movement patterns of the cyclist. Kinetic chain : The kinetic chain as a concept was first introduced in 1875, to describe the idea that the body was a collection of interacting segments, creating a system that would allow movement at one joint to affect movement of another joint within the kinetic link. Contemporary literature in the assessment and management of sporting injuries upholds the kinetic chain theory, with mechanical deficiency in one part of the activity chain being the cause of pathology in another part, especially in the case of ACL injury (Hewett 2005) and patello-femoral pain syndrome (Souza and Powers 2009). Cycling injury management has had a historical focus upon the position of the cyclist in relation to the bike, and justifiably so, but as the assessment of bike set-up evolves with the use of technology and sharing of information, deficiencies in the way the cyclist functions must become a part of the ideal bike set-up assessment. As a background we must explore the “Perfect” vs “Imperfect” technique of pedaling, and how this possible imperfect technique can be a source of pain or injury. And what are the measures which guide us in assessing that a pedal stroke is imperfect – kinematics, muscle activation, co-ordination, strength, length-tension relationships, force, power, posture? In the area of muscle activation, the historical perspective was simplistic, with the more realistic pattern represented in figure 1. And whilst the gluteals and quadriceps are seen as the main muscles for power production, co- ordination of the pedal stroke utilizing the hamstrings and calves seems an important feature of “perfect” pedaling (Figure 2 Blake 2012) FIGURE 2. Finally, given the paucity of research in the area of cause and effect regarding the kinetic chain and cycling injury, how much can we extrapolate findings for other athletes to the cyclist? Conclusion : pain and injury in the athletic population is complex in its aetiology. Clinical reasoning is essential to optimising management, and in cycling understanding the knowledge base regarding the interaction between the body and the bike is an important cornerstone to expert practice. The kinetic chain approach to analysis of cycling injury is a valid pathway and will bring cycling injury managers into line with world’s best practice in athletic injury management and prevention.

On voluntary rhythmic leg movement behaviour and control during pedalling.

The overall purpose of the present dissertation was to contribute to the understanding of voluntary human rhythmic leg movement behaviour and control. This was achieved by applying pedalling as a movement model and exposing healthy and recreationally active individuals as well as trained cyclists to for example cardiopulmonary and mechanical loading, fatiguing exercise, and heavy strength training. As a part of the background, the effect of pedalling frequency on diverse relevant biomechanical, physiological, and psychophysiological variables as well as on performance was initially explored. Freely chosen pedalling frequency is considerably higher than the energetically optimal pedalling frequency. This has been shown by others and was confirmed in the present work. As a result, pedal force is relatively low while rates of VO2 and energy turnover are relatively high during freely chosen pedalling as compared to a condition where a lower and more efficient pedalling frequency is imposed. The freely chosen pedalling frequency was in the present work, and by others, found to most likely be less advantageous than the lower energetically optimal pedalling frequency with respect to performance during intensive cycling following prolonged submaximal cycling. This stimulates the motivation to understand the behaviour and control of the freely chosen pedalling frequency during cycling. Freely chosen pedalling frequency was in the present work shown to be highly individual. In addition, the pedalling frequency was shown to be steady in a longitudinal perspective across 12 weeks. Further, it was shown to be unaffected by both fatiguing hip extension exercise and hip flexion exercise as well as by increased loading on the cardiopulmonary system at constant mechanical loading, and vice versa. Based on this, the freely chosen pedalling frequency is considered to be characterised as a highly individual, steady, and robust innate voluntary motor rhythm under primary influence of central pattern generators. The last part of the characterisation is largely based on, and supported by, work of other researchers in the field. Despite the robustness of the freely chosen pedalling frequency, it may be affected by some particular factors. As an example from the present work, freely chosen pedalling frequency during treadmill cycling increased by on average 15 to 17 rpm when power output was increased from a value corresponding to 86% and up to 165% of Wmax . This phenomenon is supported by other studies. As another example from the present work, freely chosen pedalling frequency decreased by on average 9 to 14 rpm following heavy strength training that involved both hip extension and hip flexion. Further, the present work suggested that the latter phenomenon occurred within the first week of training and was caused by in particular the hip extension strength training rather than the hip flexion strength training. The fast response to the strength training indicated that neural adaptations presumably caused the observed changes in movement behaviour. The internal organisation of the central pattern generator is by some other researchers in the field considered to be functionally separated into two components, in which, one is responsible for movement frequency and another is responsible for movement pattern. For the present dissertation, the freely chosen pedalling frequency was considered to reflect the rhythmic movement frequency of the voluntary rhythmic leg movement of pedalling. The tangential pedal force profile was considered to reflect the rhythmic movement pattern. The present work showed that fatiguing hip flexion exercise in healthy and recreationally active individuals modified the tangential pedal force profile during cycling at a pre-set target pedalling frequency in a way that the minimum tangential pedal force became more negative, the maximum tangential pedal force increased, and the phase with negative tangential pedal force increased. In other words, the legs were "actively lifted" to a lesser extent in the upstroke phase. Fatiguing hip extension exercise did not have that effect. And none of the fatiguing exercises affected the freely chosen pedalling frequency. The present work furthermore showed that the primary effect of hip extension strength training was that it decreased the freely chosen pedalling frequency. An interpretation of this could be that the hip extension strength training, in particular, influenced the output from the component of the central pattern generator that may be responsible for rhythmic movement frequency.

Effect of optimal cycling repeated-sprint combined with classical training on peak leg power in female soccer players

BACKGROUND: Muscle power is one of the most important factors influencing sport performance. Despite the variety of training methods used in the literature, more individualised, varied and enjoyable methods are needed to enhance muscle peak power in soccer. OBJECTIVE:To assess the effect of short-sprint cycle ergometer training on peak power output and field performance of female soccer players. METHODS: 7 female soccer players (age: 20.2 ± 1.5 (years); body mass: 55.1 ± 6.1 (kg); height: 1.61 ± 0.06 (m)) served as an experimental group, and seven female soccer players (age: 19.4 ± 1.5 (years); body mass: 65.2 ± 6.1 kg; height: 1.69 ± 0.08 m) as a control group. Peak power output ( ˙ W peak) during a cycle ergometer force-velocity test and field performance (5-jump test and speeds over 10, 20 and 30 m) were assessed both before and after training (3 months duration, with 3 sessions per week). Each training session comprised 2 series of 15 sprints, separated by a 15 min recovery interval. Individual sprints were of 5 sec duration, at the optimal pedalling velocity for the subject (100–110 rpm) and against the optimal frictional loading equal of the subject (7.5%–8.5% of body mass); a recovery period of 55 sec was allowed between sprints. RESULTS: The training regimen induced gains of peak power ( p< 0.05), whether expressed in ˙ W, ˙ W/kg, or relative to leg muscle volume ( ˙ W/l). There were also gains in 5-jump ( p< 0.01), and 20 and 30 m sprint velocities ( p< 0.01). Findings in the control participants remained unchanged. CONCLUSION: When combined with traditional soccer training, repeated short sprints on a cycle ergometer offer an effective strategy for enhancing leg power in female Tunisian soccer players.

Maximal torque and power pedaling rate relationships for high level BMX riders in field tests

The Bicycle Motocross race is an “all-out” sprint discipline with a race time not exceeding 40s. In high-level, the maximal power output during acceleration phase can be higher than 2000 W. The purpose of this study was to analyse the maximal torque- and power-pedaling rate relationships and anthropometric characteristics during 80m sprints. Seven elite riders performed three 80m sprints on a levelled ground. The maximal mechanical power output (PMAX), the mean pedaling rate (PRmean), the optimal pedaling rate (PROpt), the maximal theoretical pedaling rate (PR0), the maximal theoretical torque (T0), the time at 20m (t20) and the maximal velocity reached during 80m sprint (vMAX) were measured using PowerTap system and photoelectric cells. Moreover, the projected frontal area (Ap) was measured during the sprints by photographs. Significant correlations (P < 0.05) were observed between PMAX and vMAX (r = 0.99), vMAX and PMAX•Ap-1 (r = 0.87), vMAX and T0 (r = 0.97), vMAX and PRmean (r = 0.98) and t20 and vMAX (r = -0.99). Moreover there was a significant difference (P < 0.01) between PRmean and PROpt with PRmean significantly greater than PROpt (158 ± 9 vs. 122 ± 18 rpm). The main results of this study showed that PMAX, T0, PRmean, Ap and t20 were significant determining factors of performance in 80m sprint. Furthermore, a lower value of PRmean could permit to reduce the difference between PRmean and PROpt in order to maximize the power output during the sprint.

사이클 페달링 시 안장높이에 따른 하지관절 각도와 근육활성화의 상관관계

The purpose of this study was to investigate the effects of different saddle heights on lower-limb joint angle and muscle activity. Six elite cyclists(age: <TEX>$32.2{\pm}5.2years$</TEX>, height: <TEX>$171.0{\pm}3.5cm$</TEX>, weight: <TEX>$79.7{\pm}5.6kg$</TEX>, cycle career: <TEX>$13{\pm}6.2years$</TEX>) participated in three min. submaximal(90 rpm) pedaling tests with the same load and cadence based on saddle heights where subject's saddle height was determined by his knee flexion angle when the pedal crank was at the 6 o'clock position. Joint angles(hip, knee, ankle joints) and the activity of lower limb muscles(biceps femoris(BF), vastus lateralis(VL), tibialis anterior(TA) and gastrocnemius medial(GM)) were compared by measuring 3D motion and electromyography(EMG) data. Results showed that there were significant differences in minimum hip & knee joint angle and range of motion of hip and knee joint between saddle heights. Onset timing and integrated EMG of only BF among 4 muscles were significantly different between saddle heights. Especially there was a negative relationship between minimum hip joint angle and onset timing of BF in most subject, which means that onset timing of BF became fast as the degree of bending of the hip joint became larger by saddle height. Optimal pedaling will be possible through increased amount of muscle activation due to the appropriate burst onset timing by proper pedaling posture with adjusted saddle height.

Determinants of “optimal” cadence during cycling

Cadence is one of the only variables cyclists can adjust to manage their performance and fatigue during an event. Not surprisingly, cadence has received a great deal of attention from the scientific community in an effort to identify the cadence that optimizes power output while minimizing the fatigue that is incurred. The literature appears to present conflicting results with little consensus as regards the optimal pedalling cadence. This is in large part due to the inconsistent definition of the term “optimal” cadence, which has been used to describe energetic cost, muscular stress, and perception of effort. The issue is further confounded by the workload-dependent nature of the “optimal” cadence – that is, at higher power outputs, the optimized cadence is different from that at lower power outputs. Although the optimal cadence is different for energetic, muscular, and perceptual definitions, the curves that describe the effect of changes in cadence on these variables consistently exhibit a J-shaped response. This suggests that there is an underlying principle that is common to each of the definitions. Indeed, it would appear that the response of both the cardio-respiratory system (energetic cost) and the muscular system (muscular stress) is determined by the types of muscle motor units that are recruited during the exercise. Furthermore, although part of the response may be due to the inherent differences in the characteristics between the different motor units, the absolute contraction velocity relative to fibre type optimum may be of greater significance. Even when the power output is increased, the shape of the response curves to changes in cadence remains constant, although the nadir of the curve does shift to the right for increasing power outputs. We propose that the point at which the energetic vs. power and the muscular stress vs. power curves intercept is defined by the cadence at which the perceived effort is minimized (i.e. the preferred cadence). However, cadence fluctuations occur under field conditions that are unrelated to physiological factors and, therefore, the ability to identify an “optimal” cadence is limited to the laboratory environment and specific field conditions.

Maximal torque- and power-pedaling rate relationships for elite sprint cyclists in laboratory and field tests

Performance models provide an opportunity to examine cycling in a broad parameter space. Variables used to drive such models have traditionally been measured in the laboratory. The assumption, however, that maximal laboratory power is similar to field power has received limited attention. The purpose of the study was to compare the maximal torque- and power-pedaling rate relationships during "all-out" sprints performed on laboratory ergometers and on moving bicycles with elite cyclists. Over a 3-day period, seven male (mean +/- SD; 180.0 +/- 3.0 cm; 86.2 +/- 6.1 kg) elite track cyclists completed two maximal 6 s cycle ergometer trials and two 65 m sprints on a moving bicycle; calibrated SRM powermeters were used and data were analyzed per revolution to establish torque- and power-pedaling rate relationships, maximum power, maximum torque and maximum pedaling rate. The inertial load of our laboratory test was (37.16 +/- 0.37 kg m(2)), approximately half as large as the field trials (69.7 +/- 3.8 kg m(2)). There were no statistically significant differences between laboratory and field maximum power (1791 +/- 169; 1792 +/- 156 W; P = 0.863), optimal pedaling rate (128 +/- 7; 129 +/- 9 rpm; P = 0.863), torque-pedaling rate linear regression slope (-1.040 +/- 0.09; -1.035 +/- 0.10; P = 0.891) and maximum torque (266 +/- 20; 266 +/- 13 Nm; P = 0.840), respectively. Similar torque- and power-pedaling rate relationships were demonstrated in laboratory and field settings. The findings suggest that maximal laboratory data may provide an accurate means of modeling cycling performance.

Why Does Power Output Decrease at High Pedaling Rates during Sprint Cycling?

The objective of this study was to partly explain, from electromyographical (EMG) activity, the decrease in power output beyond optimal pedaling rate (PRopt) during sprint cycling. Eleven cyclists performed four 8-s nonisokinetic sprints on a cycle ergometer against four randomized friction loads (0.5, twice 0.75, and 0.9 N x kg(-1) of body mass). Power output and EMG activity of both right and left gluteus maximus, rectus femoris, biceps femoris, and vastus lateralis were measured continuously. Individual crank cycles were analyzed. Crank angles corresponding to the beginning and the peak of each downstroke and EMG burst onset and offset crank angles were computed. Moreover, crank angles corresponding to the beginning and the end of muscle force response were determined assuming a 100-ms lag time between the EMG activity and the relevant force response (or electromechanical delay). Muscle coordination (EMG onset and offset) was altered at high pedaling rates. Thus, crank angles corresponding to muscle force response increased significantly with pedaling rate. Consequently, at pedaling rates higher than the optimal pedaling rate, force production of lower-limb extensor muscles was shifted later in the crank cycle. Mechanical data confirmed that downstrokes occurred later in the crank cycle when pedaling rate increased. Hence, force was produced on the pedals during less effective crank cycle sectors of the downstroke and during the beginning of the upstroke. During nonisokinetic sprint cycling, the decrease in power output when pedaling rates increased beyond PRopt may be partly explained by suboptimal muscle coordination.

Cadência de pedalada no ciclismo: uma revisão de literatura

After decades of studies and innumerable quarrels, there is not still a consensus on the optimal pedaling rate in the cycling. The present study aimed to review systematically the scientific studies that investigated the mechanical efficiency through the pedaling rates in cycling. Such experiments have demonstrated that diverse factors could be capable to modify the optimal pedaling preferred rate and pedaling efficiency as well. The conclusive point of literature defines the low pedaling cadences as more economic and efficient that the high ones. The ideal cadence for the majority of the practitioners is generally lower than the cadence preferred by the trained cyclists.

Optimal Pedaling Rate in Bicycle Ergometer Exercise Determined by Probe Reaction Time

The purpose of this study was to obtain the optimal pedaling rate in bicycle ergometer exercise by measuring probe reaction time, which is a good indicator of attention demand, by changing workloads and pedaling rates, and to discuss the relevant rhythm of lower limb movement. Subjects were 19 healthy men whose M age was 22.8 yr. They were instructed to pedal a bicycle ergometer, and their reaction time at different workloads and pedaling rates was measured to estimate an optimal pedaling rate. Probe reaction time was measured under the conditions as follows: pedaling rate of 20, 40, 60, 80, and 100 rpm at each workload of 40, 60, 80, 100, and 120 watts. The estimated values obtained by regression analysis for pedaling rate to give the minimum probe reaction time were 63.5 rpm for 40 watts, 58.8 rpm for 60 watts, 61.3 rpm for 80 watts, 63.4 rpm for 100 watts, and 64.8 rpm for 120 watts. These results indicated that the optimal pedaling rate was approximately 60 rpm regardless of the workload.

Biomechanical Determinants of Metabolic Cost of Submaximal Cycling Power

Previous authors have reported that metabolic cost increases linearly with increasing net mechanical cycling power output. This metabolic cost has also been reported to increase with increasing pedaling rate. Several investigators have speculated that the mechanism responsible for the effect of pedaling rate might be increased negative work. PURPOSE: We conducted this study to determine the relationship of metabolic cost of producing submaximal cycling power with summed net and positive powers at the ankle, knee, and hip, and to test the hypothesis that positive joint powers would account for previously reported differences in metabolic cost associated with different pedaling rates. METHODS: Five trained cyclists [31.8±8 yrs, 178±9 cm, 74.8±11 kg] cycled at 60, 90, and 120 rev/min, at intensities of 30, 60, and 90% of ventilatory threshold. Pedal forces, and pedal and crank position were sampled at 120 Hz for 20 sec. Hip position and geometrically calculated leg kinematics were determined from 20 sec of recorded motion capture data. Net joint moments and reaction forces were determined using inverse dynamic techniques. Ankle, knee, and hip joint powers were calculated as the product of net joint moment and joint angular velocity and power transferred across the hip joint was calculated as the dot product of joint reaction force and joint linear velocity. Pedal force and position data were recorded in the fifth minute of each trial. Expired gases were collected throughout the trial and values during the fifth minute were averaged and used to calculate metabolic cost via the Weir equation. Multiple linear regression analyses were used to determine the relationship between metabolic cost and pedaling rate with two measures of power: net joint power and net positive joint power. RESULTS: Both regression analyses produced significant relationships (R2 > 0.94, p <0.001) but the pedaling rate coefficient was positive when predicting net joint power but negative when predicting positive joint power. CONCLUSIONS: Our novel finding was that the metabolic cost of producing positive power decreased with increasing pedaling rate. We interpret these results to suggest that a pedaling rate of 120 rpm, which has been reported to be the optimal pedaling rate for producing maximum cycling power, allowed for more efficient positive joint power production. The commonly reported increase in metabolic cost associated with increasing pedaling rate appears to be due to the additional power required to overcome negative joint powers. Whether negative powers represent poor technique or are required to stabilize the 2 degree of freedom leg system is a topic of ongoing investigation in our lab.

Performance at High Pedaling Cadences in Well-Trained Cyclists

This study was conducted to determine the effect of high pedaling cadences on maximal cycling power output (W(max)). Nine well-trained cyclists performed a continuous, incremental cycle-ergometer test to exhaustion (25 W increases every 3 min) either at 80, 100, or 120 rpm on three different occasions. W(max) was approximately 9% lower during 120 rpm in comparison with 80 and 100 rpm (335 +/- 9, 363 +/- 7, and 370 +/- 12 W, respectively; P < 0.05). During 120 rpm, ventilation rate (V(E)) increased above the increases in expired CO(2), which reduced the power output (PO) at the ventilatory anaerobic threshold (VT(2)) by 11% (P < 0.05). Gross efficiency (GE) did not differ among trials. At 120 rpm, capillary blood lactate concentration ([Lac]) increased above the 80-rpm trial (5.3 +/- 1.2 vs 3.0 +/- 0.7 mM at 300 W; P < 0.05), although pH was not reduced. At 120 rpm, expired CO(2) increased and reduced blood bicarbonate concentration ([HCO(3)(-)]) was reduced, maintaining blood pH similar to the other trials. A high pedaling cadence (i.e., 120 rpm) reduces performance (i.e., W(max)) and anaerobic threshold during an incremental test in well-trained cyclists. The data suggest that ventilatory anaerobic threshold (VT(2)) is a sensitive predictor of optimal pedaling cadence for performance, whereas blood pH or efficiency is not.

Torque and Power-Velocity Relationships in Cycling: Relevance to Track Sprint Performance in World-Class Cyclists

The aims of the present study were both to describe anthropometrics and cycling power-velocity characteristics in top-level track sprinters, and to test the hypothesis that these variables would represent interesting predictors of the 200 m track sprint cycling performance. Twelve elite cyclists volunteered to perform a torque-velocity test on a calibrated cycle ergometer, after the measurement of their lean leg volume (LLV) and frontal surface area (A(p)), in order to draw torque- and power-velocity relationships, and to evaluate the maximal power (P(max)), and both the optimal pedalling rate (f(opt)) and torque (T(opt)) at which P (max) is reached. The 200 m performances--i.e. velocity (V200) and pedalling rate (f 200)--were measured during international events (REC) and in the 2002 French Track Cycling Championships (NAT). P(max), f(opt), and T(opt) were respectively 1600 +/- 116 W, 129.8 +/- 4.7 rpm and 118.5 +/- 9.8 N . m. P(max) was strongly correlated with T(opt) (p < 0.001), which was correlated with LLV (p < 0.01). V200 was related to P(max) normalized by A(p) (p < or = 0.05) and also to f(opt) (p < 0.01) for REC and NAT. f 200 (155.2 +/- 3, REC; 149 +/- 4.3, NAT) were significantly higher than f(opt) (p < 0.001). These findings demonstrated that, in this population of world-class track cyclists, the optimization of the ratio between P(max) and A(p) represents a key factor of 200 m performance. Concerning the major role also played by f(opt), it is assumed that, considering high values of f 200, sprinters with a high value of optimal pedalling rate (i.e. lower f200-f(opt) difference) could be theoretically in better conditions to maximize their power output during the race and hence performance.