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Purpose: To investigate how cycling time-trial (TT) performance changes over a cycling season, both in a "fresh" state and in a "fatigued" state (durability). Additionally, the aim was to explore whether these changes are related to changes in underlying physiological factors such as gross efficiency, energy expenditure (EE), and substrate oxidation (fat oxidation [FatOx] and carbohydrate oxidation [CarbOx]). Methods: Sixteen male semiprofessional cyclists visited the laboratory on 3 occasions during a cycling season (PRE, START, and IN) and underwent a performance test in both fresh and fatigued states (after 38.1 [4.9] kJ/kg), containing a submaximal warm-up for the measurement of gross efficiency, EE, FatOx, and CarbOx and a maximal TT of 1 (TT1min) and 10 minutes (TT10min). Results were compared across states (fresh vs fatigued) and periods (PRE, START, and IN). Results: The average power output (PO) in TT1min decreased (P <.05) from fresh to fatigued state across all observed periods, whereas there was no change in the PO in TT10min. Over the course of the season, the PO in TT1min in the fatigued state improved more compared with the PO in TT1min in the fresh state. Furthermore, while EE did not significantly change, there was an increase in FatOx and a decrease in CarbOx toward the fatigued state. These changes diminished during the cycling season (IN), indicating a greater contribution of CarbOx in the fatigued state. Conclusions: TT1min performance is more sensitive to fatigue compared with TT10min. Also, during a cycling season, durability improves more when compared with fresh maximal POs, which is also observed in the changes in substrate oxidation. [ABSTRACT FROM AUTHOR]

This study investigated whether repeated transitions between seated and standing positions has a different physiological response compared to continuous use of either seated position or standing position during steep uphill cycling among elite cyclists. Ten elite male cyclists completed three 5-min treadmill cycling tests at an inclination of 6.8° with constant individual-based speed resulting in a work intensity close to the aerobic threshold. During the first and third test, the participants used standing position (ST test) and seated position (SE test) or vice versa, whereas in the second test, they made repeated transitions between standing and seated positions every 10 s (RT test). The last 2 min of each test was used to measure the mean values of oxygen uptake (V̇O2) and respiratory exchange ratio, which were used to calculate the metabolic rate (MR) and gross efficiency (GE). Additionally, the blood-lactate concentration before and after (Lapost) each test was determined. One-way repeated measures ANOVA was used to determine the effect of cycling position on the physiological response. No significant differences between tests were observed for the variables related to aerobic energy expenditure (i.e., V̇O2, MR and GE), whereas the RT test was associated with a significantly lower Lapost compared to the ST and SE tests. Steep uphill cycling, at an intensity close to the aerobic threshold, with repeated transitions between standing and seated positions, did not have a higher oxygen consumption; instead, the blood-lactate concentration was lower during the RT test compared to that under continuous use of either seated or standing position. [ABSTRACT FROM AUTHOR]

Purpose: There are several published equations to calculate energy expenditure (EE) from gas exchanges. The authors assessed whether using different EE equations would affect gross efficiency (GE) estimates and their reliability. Methods: Eleven male and 3 female cyclists (age 33 [10] y; height: 178 [11] cm; body mass: 76.0 [15.1] kg; maximal oxygen uptake: 51.4 [5.1] mL·kg−1·min−1; peak power output: 4.69 [0.45] W·kg−1) completed 5 visits to the laboratory on separate occasions. In the first visit, participants completed a maximal ramp test to characterize their physiological profile. In visits 2 to 5, participants performed 4 identical submaximal exercise trials to assess GE and its reliability. Each trial included three 7-minute bouts at 60%, 70%, and 80% of the gas exchange threshold. EE was calculated with 4 equations by Péronnet and Massicotte, Lusk, Brouwer, and Garby and Astrup. Results: All 4 EE equations produced GE estimates that differed from each other (all P <.001). Reliability parameters were only affected when the typical error was expressed in absolute GE units, suggesting a negligible effect—related to the magnitude of GE produced by each EE equation. The mean coefficient of variation for GE across different exercise intensities and calculation methods was 4.2%. Conclusions: Although changing the EE equation does not affect GE reliability, exercise scientists and coaches should be aware that different EE equations produce different GE estimates. Researchers are advised to share their raw data to allow for GE recalculation, enabling comparison between previous and future studies. [ABSTRACT FROM AUTHOR]

Triathlon is a multisport composed of swim, cycle, and run segments and two transition periods. The swim-to-cycle transition is considered a critical period for the change in body position and the modifications in physiological (heart rate, VO2, lactate) and biomechanical parameters (cycling power and cadence, swimming stroke rate). Therefore, the aim of this review was to summarize the current evidence regarding the physiological and biomechanical changes and their interlink during the swim-to-cycle transition hinting at practical recommendations for coaches and athletes. The influence of the swim segment on cycle one is more evident for short-distance events. Greater modifications occur in athletes of lower level. The modulation of intensity during the swim segment affects the changes in the physiological parameters (heart rate, blood lactate, core temperature), with a concomitant influence on cycling gross efficiency. However, gross efficiency could be preserved by wearing a wetsuit or by swimming in a drafting position. A higher swim leg frequency during the last meters of the segment induces a higher cadence during the cycle segment. Training should be directed to the maintenance of a swimming intensity around 80–90% of a previous maximal swim test and with the use of a positive pacing strategy. When athletes are intended to train consecutively only swim and cycle segments, for an optimal muscle activation during cycling, triathletes could adopt a lower cadence (about 60–70% of their typical cadence), although an optimal pedaling cadence depends on the level and type of athlete. Future research should be focused on the combined measurements of physiological and biomechanical parameters using an intervention study design to evaluate training adaptations on swim kick rate and their effects on cycling performance. Coaches and athletes could benefit from the understanding of the physiological and biomechanical changes occurring during the swim-to-cycle transition to optimize the overall triathlon performance. [ABSTRACT FROM AUTHOR]

This study examined the physiological effects of crushed ice ingestion before steady state exercise in the heat. Ten healthy males with age (23 ± 3 y), height (176.9 ± 8.7 cm), body-mass (73.5 ± 8.0 kg), VO2peak (48.5 ± 3.6 mLkgmin-1) participated in the study. Participants completed 60 min of cycling at 55% of their VO2peak preceded by 30 min of precooling whereby 7 g⋅kg-1 of thermoneutral water (CON) or crushed ice (ICE) was ingested. The reduction in Tc at the conclusion of precooling was greater in ICE (-0.9 ± 0.3 °C) compared with CON (-0.2 ± 0.2 °C) (p £ .05). Heat storage capacity was greater in ICE compared with CON after precooling (ICE -29.3 ± 4.8 W⋅m-2; CON -11.1 ± 7.3 W⋅m-2, p < .05). Total heat storage was greater in ICE compared with CON at the end of the steady state cycle (ICE 62.0 ± 12.5 W⋅m-2; CON 49.9 ± 13.4 W⋅m-2, p < .05). Gross efficiency was higher in ICE compared with CON throughout the steady state cycle (ICE 21.4 ± 1.8%; CON 20.4 ± 1.9%, p < .05). Ice ingestion resulted in a lower thermal sensation at the end of precooling and a lower sweat rate during the initial stages of cycling (p < .05). Sweat loss, respiratory exchange ratio, heart rate and ratings of perceived exertion and thirst were similar between conditions (p > .05). Precooling with crushed ice led to improved gross efficiency while cycling due to an increased heat storage capacity, which was the result of a lower core temperature. [ABSTRACT FROM AUTHOR]

Previous research showed that gross efficiency (GE) declines during exercise and therefore influences the expenditure of anaerobic and aerobic resources. PURPOSE: To calculate the anaerobic work produced during cycling time trials of different length, with and without a GE correction. METHODS: Anaerobic work was calculated in 18 trained competitive cyclists during 4 time trials (500, 1000, 2000, and 4000-m). Two additional time trials (1000 and 4000 m) that were stopped at 50% of the corresponding "full" time trial were performed to study the rate of the decline in GE. RESULTS: Correcting for a declining GE during time-trial exercise resulted in a significant (P < .001) increase in anaerobically attributable work of 30%, with a 95% confidence interval of [25%, 36%]. A significant interaction effect between calculation method (constant GE, declining GE) and distance (500, 1000, 2000, 4000 m) was found (P < .001). Further analysis revealed that the constant-GE calculation method was different from the declining method for all distances and that anaerobic work calculated assuming a constant GE did not result in equal values for anaerobic work calculated over different time-trial distances (P < .001). However, correcting for a declining GE resulted in a constant value for anaerobically attributable work (P = .18). CONCLUSIONS: Anaerobic work calculated during short time trials (<4000 m) with a correction for a declining GE is increased by 30% [25%, 36%] and may represent anaerobic energy contributions during high-intensity exercise better than calculating anaerobic work assuming a constant GE. [ABSTRACT FROM AUTHOR]

Recumbent and supine cycling are common exercise modes in rehabilitation and clinical settings but the influence of postures on work efficiency is unclear. Therefore, the aim of this study was to compare metabolic and ventilatory efficiency during upright, recumbent, and supine postures. Potential differences should be assessed for suitable diagnostics and for prescriptions of training that probably is performed in alternative postures. Eighteen healthy subjects (age: 47.2 ± 18.4 years; 10 female, 8 male) participated in the study and each completed three incremental cycle ergometer tests until exhaustion in upright, recumbent (40°), and supine positions. Gas exchange, heart rate (HR), and lactate concentrations were analyzed and efficiency was calculated subsequently. Testing sessions were performed in random order within a 2-week period. Upright cycling resulted in significantly higher peak values [power output, oxygen uptake (Vo2), HR] as well as performance at lactate and ventilatory thresholds in comparison to recumbent or supine positions. Vco2/Vo2 slope and ventilatory efficiency (VE/Vco2 slope) were not affected by posture. Aerobic work efficiency (Vo2/P slope) and gross efficiency (GE) differed significantly between postures. Hereby, GE was lowest in supine cycling, particularly obvious in a mainly aerobic condition at 70 Watt [Median 11.6 (IQR 10.9–13.3) vs. recumbent: 15.9 (IQR 15.6–18.3) and upright: 17.4 (IQR 15.1–18.3)]. Peak power as well as GE and work efficiency values are influenced by cycling position, reinforcing the importance of adjusting test results for training prescriptions. Surprisingly, ventilatory efficiency was not affected in this study and therefore does not seem to falsify test results for pulmonary diagnostics.

Cycling technique is steeped in cultural lore. One deeply held belief is that “pulling up” to lift the leg (increased muscular leg flexion) will optimize technique and improve efficiency. In contrast, scientific evidence suggests that when cyclists are instructed to pull-up efficiency decreases. However, such interventions may not have allowed sufficient time for cyclists to adapt and refine their technique. This case study documented how a cyclist with a complete unilateral limb amputation consumed metabolic power to produce mechanical power during single-leg cycling. The cyclist was a four time US National Paralympic Champion who performed single-leg cycling for 7 yr and thus was fully adapted to pull up. We hypothesized that a counterweight system, which reduced the requirement to pull up, would decrease metabolic power and increase efficiency for this cyclist. The cyclist performed submaximal cycling (100, 135, 170, 205 W, 80 rpm, 5 min) with and without a counterweight (10 kg) on the unused crank. Expired gases were measured, and metabolic power and gross efficiency were calculated. Metabolic power decreased on average by 87 ± 7 W (P < 0.001) and gross efficiency increased from 16.3 ± 1.9 to 18.0 ± 1.8% (P < 0.001) when cycling with the counterweight. During counterweighted single-leg cycling, the metabolic power of unloaded cycling decreased (317 vs. 238 W) and delta efficiency was similar (25.2 vs. 25.5%). Results demonstrated that significant metabolic power was associated with pulling up to produce muscular leg flexion power even in a cyclist who pulled up substantially during cycling. Our findings confirm observations from previous studies that altered pedaling technique acutely and indicate that pulling up during cycling is less efficient. NEW & NOTEWORTHY This study offers unique insight into pedaling technique and provides the “final nail in the coffin” to the notion that pulling up improves cycling efficiency. When the requirement for pulling up was reduced with the counterweight, the cyclist immediately benefited as the cost to move the limb decreased and gross efficiency increased. These case study results along with previous research suggest that, in general, cyclists should not adopt pedaling techniques, which increase the action of pulling up. [ABSTRACT FROM AUTHOR]

BACKGROUND: The purpose of this study was to evaluate changes to key aerobic performance determinants, namely maximal oxygen uptake (VO 2max), lactate threshold (LT) and gross efficiency (GE) over the cycling season. METHODS: Twelve well-trained road cyclists completed three incremental tests during a season in order to determine VO 2max , LT and GE. The laboratory tests were performed using the following sequence: after the transition period (TRAN), during the preparatory period (PREP) and during the competition period (COMP). RESULTS: VO 2max did not change significantly over the season. Workload at lactate threshold (WL LT) increased by 11% between the TRAN and COMP periods (p < 0.001), which was accompanied by an increase in oxygen uptake at lactate threshold (VO 2LT ; p < 0.01). The percentage of VO 2max at the LT changed from 80.1% to 85.6% (p < 0.05). GE increased from 21.9 ± 1.1% in TRAN to 22.8 ± 0.8% in COMP (p < 0.01). No significant correlations were found between VO 2max and GE and between changes in GE and those in VO 2max in any training period. CONCLUSIONS: In well-trained athletes, the training process contributes mostly to improvements in submaximal indicators, while it does not change VO 2max. GE is an indicator that is expected to improve over the season, but further research is needed to explain the mechanisms responsible for the individual fluctuations of the GE value in athletes. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of antioxidant supplementation on intense endurance exercise performance and the physiologic exercise response acutely and in early recovery.Methods: Well-trained cyclists (n = 11, peak VO2: 69 ± 7 ml/min/kg) completed two identical standardized 20-min warm-up periods (WU-1 and WU-2) prior to two performance tests (PT) with a duration of ~ 4 min representing a qualifying (PT-1) and final race (PT-2) on the same day separated by 90 min. Subjects were supplemented orally with placebo (PLA) and N-acetyl cysteine (NAC; 20 mg/kg) before exercise in a double-blinded crossover design.Results: Mean power during PT-1 did not differ (P = 0.39) between PLA (400 ± 44 W) and NAC (401 ± 44 W) as was the case during PT-2 with similar performance (P = 0.74) between PLA (401 ± 43 W) and NAC (400 ± 42 W). Subjective "readiness" was lowered by prior exhaustive exercise from PT-1 to PT-2 (P = 0.012) in both PLA and NAC. Plasma total antioxidant capacity was not affected by supplementation and prior exhaustive exercise (respective main effects: P = 0.83 and P = 0.19) which also was observed for peak VO2 at ~ 5 L/min (P = 0.84 and P = 0.30). In WU-1 and WU-2, both cycling economy at ~ 20% (P = 0.10 and P = 0.21) and plasma potassium at ~ 5 mmol/L (P = 0.46 and P = 0.26) were unaffected by supplementation and prior exercise.Conclusions: Athletes executing maximal efforts of a ~ 4-min duration twice daily, as seen in track cycling, appear to gain no benefit from oral NAC supplementation on acute and subsequent performance following short-term recovery. Moreover, well-trained cyclists exhibit rapid recovery from a single bout of intense endurance cycling. [ABSTRACT FROM AUTHOR]

Purpose. The research aim was to determine the relationship between gross efficiency (E) and the ability to repeat the given pressure force (ARGPF). Methods. A group of 23 road cyclists performed an incremental exercise test on a cycle ergometer and a repeated isometric force test (RIFT) with lower and upper limbs. E was calculated on the basis of the estimated energy expenditure (EE) during the last 30 seconds of the submaximal work with the loads of E-100W, E-150W, E-200W, E-250W, E-300W. During RIFT, carried out on a kinesthesiometer with strain gauges, the subjects performed pressures with the force of 10 kg with upper limbs and 20 kg with lower limbs. RIFT was performed immediately before and after the incremental test; the data served to express ARGPF by means of the repeated given pressure force (RGPF) value. Results. Post-exercise RGPF for the left lower limb significantly correlated with E at all incremental test loads (r: 0.64, 0.72, 0.7, 0.63, 0.62, respectively, for 100 W, 150 W, 200 W, 250 W, and 300 W). Pre-exercise RGPF for the left upper limb significantly correlated with E at 100 W, 150 W, and 200 W loads (r: 0.68, 0.72, 0.62, respectively). Both RGPF for limbs and E positively and statistically significantly correlated with the cyclists' age. Conclusions. Road cyclists with higher E presented greater variability of the repeated pressure force of the left limbs. Both characteristics show a strong relationship with the cyclists' age, which may indicate that their development depends on training experience. [ABSTRACT FROM AUTHOR]

The present study investigated the effects of initial levels of cycling performance, peak oxygen uptake (O2peak) and gross efficiency (GE) on the subsequent adaptations of these variables and their relationship following high-intensity training (HIT) designed to increase O2peak in competitive cyclists. Sixty cyclists (O2peak = 61 ± 6 mL kg-1 min-1) were assigned a 12-week training program consisting of twenty-four supervised high-intensity interval training sessions and ad libitum low intensity training. GE was calculated at 125, 175, and 225 W and performance was determined by mean power during a 40-min time-trial (Power40 min). In addition to correlation analyses between initial level and pre- to post-intervention changes of the different variables, we compared these changes between four groups where participants were categorized with either low and/or high initial levels of O2peak and GE. Average volume of high- and low-intensity training during the 12-week intervention was 1.5 ± 0.3 and 8.3 ± 2.7 h·week-1, respectively. Following the 12-week training period, there was a significant increase in absolute and body mass normalized O2peak and Power40 min (p < 0.05) and a significant decrease in GE (p < 0.05) for all athletes pooled. There was no change in body mass following the 12-week training period. We found a moderate negative correlation between initial level of O2peak and the change in O2peak following the training period (r = -0.32; p < 0.05). A small negative correlation was also found between initial Power40 min and its change following training both when expressed in absolute power and power normalized for body mass (r = -0.27 and -0.28; both p < 0.05). A moderate negative correlation was also found between initial levels for GE and its change following training (r = -0.44; p < 0.01). There were no differences between the four groups based on initial levels of O2peak and GE in the response to training on O2peak, GE, or Power40 min (all p > 0.12). In conclusion, the present findings suggest that there are statistically significant effects of initial levels of cycling performance and O2peak and on the subsequent adaptations following a 12-week HIT program, but the small and moderate effects indicate limited influence on training practice.

The purpose of our study was to assess physiological adaptations and measure mood outcomes following a cycling training camp in competitive athletes. Fourteen competitive athletes (8 males, 6 females) performed 2 incremental tests to exhaustion before and after a training camp. Volume and intensity (load) of the training regimen were recorded. Submaximal and maximal metabolic data were analysed, as well as economy variables (gross mechanical efficiency and cycling economy). Skeletal muscle adaptations were assessed using near infrared spectroscopy (NIRS). For both genders (n = 14), peak power output, peak power output-W/kg ratio and peak power output-B[La] were significantly increased (p < 0.05) after the cycling training camp (p < 0.05). Significant increases occurred for gross mechanical efficiency measured at the lactate threshold (+4.9%) and at the same precamp lactate threshold power output (+2.9%). At the lactate threshold and Post Camp Lactate Threshold Power, cycling economy increased by 5.2 and 2.9%, respectively (p < 0.05). These power measurements were significantly correlated with individual fluctuations in deoxyhaemoglobin in the vastus lateralis for male cyclists only. Profile of Mood State questionnaire results showed that subcategories "Tension-Anxiety", "Confusion", "Fatigue" and "Total Global Score" significantly decreased after the training camp. Cycling training camps were associated with positive adaptations (increased cycling economy, gross mechanical efficiency and power output) as well as some mental benefits. This indicates that despite some significant physiological adaptations participants probably did not overreach during their CTC. [ABSTRACT FROM AUTHOR]

The present study investigated the effects of initial levels of cycling performance, peak oxygen uptake ( O2peak) and gross efficiency (GE) on the subsequent adaptations of these variables and their relationship following high-intensity training (HIT) designed to increase O2peak in competitive cyclists. Sixty cyclists ( O2peak = 61 ± 6 mL kg-1 min-1) were assigned a 12-week training program consisting of twenty-four supervised high-intensity interval training sessions and ad libitum low intensity training. GE was calculated at 125, 175, and 225 W and performance was determined by mean power during a 40-min time-trial (Power40 min). In addition to correlation analyses between initial level and pre- to post-intervention changes of the different variables, we compared these changes between four groups where participants were categorized with either low and/or high initial levels of O2peak and GE. Average volume of high- and low-intensity training during the 12-week intervention was 1.5 ± 0.3 and 8.3 ± 2.7 h·week-1, respectively. Following the 12-week training period, there was a significant increase in absolute and body mass normalized O2peak and Power40 min (p < 0.05) and a significant decrease in GE (p < 0.05) for all athletes pooled. There was no change in body mass following the 12-week training period. We found a moderate negative correlation between initial level of O2peak and the change in O2peak following the training period (r = -0.32; p < 0.05). A small negative correlation was also found between initial Power40 min and its change following training both when expressed in absolute power and power normalized for body mass (r = -0.27 and -0.28; both p < 0.05). A moderate negative correlation was also found between initial levels for GE and its change following training (r = -0.44; p < 0.01). There were no differences between the four groups based on initial levels of O2peak and GE in the response to training on O2peak, GE, or Power40 min (all p > 0.12). In conclusion, the present findings suggest that there are statistically significant effects of initial levels of cycling performance and O2peak and on the subsequent adaptations following a 12-week HIT program, but the small and moderate effects indicate limited influence on training practice. [ABSTRACT FROM AUTHOR]

The efficiency of energy conversion of aerobic metabolism to external work is of great importance to sports exercise. Despite this fact, gross efficiency (GE) is not commonly used as a parameter in the assessment of cyclists’ exercise ability. It is also known that road cyclists traverse most of their route at a work intensity below the anaerobic threshold (AT). We tried to examine the relationship between the standard aerobic parameters used for defining the endurance of cyclists and GE, measured just below the anaerobic threshold. Fifty cyclists were subjected to a progressive test. Work done and the basic respiratory and circulatory parameters were measured. Gross efficiency was calculated at work intensity just below AT. We observed a very low correlation (R = –0.137) between GE (24.9 ±2.06) and maximal oxygen uptake (VO2max) – 63.8 ±6,27 ml × kg–1 × min–1. The strongest correlation (R = –0.258) was recorded between GE and the percentage of maximal oxygen consumption (58.9 ±7.0%) for the load prior to the occurrence of the anaerobic threshold. The weak, but existing correlation between GE and selected respiratory and circulatory parameters may suggest that GE provides unique and independent information about the examined athletes.

The article presents a study conducted to determine the effects of kinesiology tape, Rocktape (RT) on the perceived exertion ratings and efficiency of cycling among recreational cyclists. Topics discussed includes determining maximal oxygen consumption peak with RT and without RT, calculation of ratio of work performed to expended energy and use of analysis of variance to measure the difference between intensity and tape conditions.

To assess the effect of dietary manipulation on gross efficiency (GE), 15 trained male cyclists completed 3 × 2 h tests at submaximal exercise intensity (60 % Maximal Minute Power). Using a randomized, crossover design participants consumed an isoenergetic diet (~4 000 kcal.day-1) in the 3 days preceding each test, that was either high in carbohydrate (HighCHO, [70 % of the total energy derived from carbohydrate, 20 % fat, 10 % protein]), low in carbohydrate (LowCHO, [70 % fat, 20 % carbohydrate, 10 % protein]) or contained a moderate amount of carbohydrate (ModCHO, [45 % carbohydrate, 45 % fat, 10 % protein]). GE along with blood lactate and glucose were assessed every 30 min, and heart rate was measured at 5 s intervals throughout. Mean GE was significantly greater following the HighCHO than the ModCHO diet (HighCHO = 20.4 % ± 0.1 %, ModCHO = 19.6 ± 0.2 %; P < 0.001). Additionally, HighCHO GE was significantly greater after 25 min (P = 0.015) and 85 min (P = 0.021) than in the LowCHO condition. Heart rate responses in the HighCHO condition were significantly lower than during the LowCHO tests (P = 0.005). Diet had no effect on blood glucose or lactate (P > 0.05). This study suggests that before the measurement of gross efficiency, participants’ diet should be controlled and monitored to ensure the validity of the results obtained. [ABSTRACT FROM AUTHOR]

The objective of this study is to compare the effects of constant- and variable-intensity cycling on gross efficiency (GE) and to compare estimates of energy expenditure (EE) made using indirect calorimetry (CAL) with estimates derived from commercially available power meters. Methods: Nine national team female road cyclists completed a GE test (GEtest = 4 min at approximately 45%, approximately 55%, approximately 65%, and approximately 75% maximal aerobic power (MAP)) before and after 10.5 min of either constant- (CON)- or variable- (VAR)- intensity cycling averaging approximately 55% MAP. GE measured before, after, and during CON and VAR cycling was compared. Total EE (Id) for 10.5 min of VAR cycling was estimated using indirect CAL and compared with estimates on the basis of mechanical power [Schoberer Rad Messtechnik (SRM)] using the group mean GE, each athlete's mean GE, and each athlete's power to GE regression. Results: There was no effect of VAR on GEtests (P = 0.74). GE reduced from 19.1% ± 0.4% (mean ± SE) during the pretrial GEtests to 18.7% ± 0.4% during the posttrial GEtests (P < 0.05) in both conditions. Differences in GE (mean + SD) measured during CON (18.4% ± 1.6%) and VAR cycling (18.6% ± 1.1%) were trivial (P = 0.28). SRM-based estimates of EE were most accurate when using individual athlete's power GE regression using Pre- and Post-VAR GEtest, data combined (Δ ̄X (%) ± 90% CI, 0.3 ± 0.8; R2 0.98, P <0.001). Group mean estimates were within approximately 1% of CAL, although individual errors were approximately 11%. Conclusion: Findings support the use of calibrated power meters for estimating cycling EE. For trained female road cyclists, total mechanical work (kj) multiplied by 5.3 (GE = 19%) provides a valid estimation of total EE during variable-intensity cycling <75% MAP, although determining each athlete's GE improves accuracy greatly. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the influence of age, training status, and muscle fiber-type distribution on cycling efficiency. Forty men were recruited into one of four groups: young and old trained cyclists, and young and old untrained individuals. All participants completed an incremental ramp test to measure their peak O2 uptake, maximal heart rate, and maximal minute power output; a submaximal test of cycling gross efficiency (GE) at a series of absolute and relative work rates; and, in trained participants only, a 1-h cycling time trial. Finally, all participants underwent a muscle biopsy of their right vastus lateralis muscle. At relative work rates, a general linear model found significant main effects of age and training status on GE (P < 0.01). The percentage of type I muscle fibers was higher in the trained groups (P < 0.01), with no difference between age groups. There was no relationship between fiber type and cycling efficiency at any work rate or cadence combination. Stepwise multiple regression indicated that muscle fiber type did not influence cycling performance (P > 0.05). Power output in the 1-h performance trial was predicted by average O2 uptake and GE, with standardized β-coefficients of 0.94 and 0.34, respectively, although some mathematical coupling is evident. These data demonstrate that muscle fiber type does not affect cycling efficiency and was not influenced by the aging process. Cycling efficiency and the percentage of type I muscle fibers were influenced by training status, but only GE at 120 revolutions/min was seen to predict cycling performance. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the effect of "Pose" cycling (a combination of specific bicycle setup and pedaling technique) on metabolic efficiency and pedaling mechanics. Eighteen recreational cyclists were tested for efficiency and pedaling mechanics during steady-state cycling (90% gas-exchange threshold) using two different bicycle setups (preferred and "Pose") and three different pedaling rates (70, 90 and 110 rpm). Nine of the participants underwent a coaching intervention (4 × 1 h) consisting of drills based on the "Pose" instruction manual. The remaining nine participants did not receive an intervention. All participants were tested before and after the intervention period. Analyses of variance were performed to test the independent effects of the "Pose"-specific bicycle setup and pedaling technique on gross efficiency and pedaling mechanics. The "Pose"-specific bicycle setup resulted in increased gross efficiency at each pedaling rate compared to the participants' preferred bicycle position (P < 0.05). This increase in efficiency was accompanied by a significant increase in trunk frontal area (P < 0.05). The coaching intervention resulted in decreased gross efficiency at 110 rpm (P < 0.05); at this pedaling rate the intervention resulted in a slight increase in the non-muscular contribution to pedal power in the experimental group and a decrease in the control group. The combination of changed bicycle setup and pedaling technique had no effect on gross efficiency and only small effects on pedaling mechanics. Our findings add to a growing body of literature that short-term interventions in pedaling technique can change pedaling mechanics but do not improve efficiency during steady-state cycling. [ABSTRACT FROM AUTHOR]

The article discusses a study that compares the anaerobic capacity based on maximal accumulated oxygen deficit (MAOD) method with that based on gross efficiency (GE) method. The study involved 15 healthy male cyclists who refrained from strenuous exercise a day prior to the tests. It concludes that while the 4+Y MAOD procedure and GE method results in the most precise values of the anaerobic capacity it cannot point which of the indirect methods results in the real anaerobic capacity values.

The aim of this study was to examine differences in cycling efficiency between competitive male and female cyclists. Thirteen trained male (mean + SD: 34 ± 8 yr, 74.1 ± 6.0 kg, Maximum Aerobic Power (MAP) 414 ± 40 W, VO2max 61.3 ± 5.4 ml·kg-1·min-1) and 13 trained female (34 ± 9 yr, 60.1 ± 5.2 kg, MAP 293 ± 22 W, VO2max 48.9 ± 6.1 ml·kg-1·min-1) competitive cyclists completed a cycling test to ascertain their gross efficiency (GE). Leg and lean leg volume of all cyclists was also measured. Calculated GE was significantly higher in female cyclists at 150W (22.5 ± 2.1 vs 19.9 ± 1.8%; p < 0.01) and 180W (22.3 ± 1.8 vs 20.4 ± 1.5%; p = 0.01). Cadence was not significantly different between the groups (88 ± 6 vs 91 ± 5 rev·min-1). Lean leg volume was significantly lower for female cyclists (4.04 ± 0.5 vs 5.51 ± 0.8 dm³; p < 0.01) and was inversely related to GE in both groups at 150 and 180W (r = -0.59 and -0.58; p < 0.05). Lean leg volume was shown to account for the differences in GE between the males and females. During an "unloaded" pedalling condition, male cyclists had a significantly higher O2 cost than female cyclists (1.0 ± 0.1 vs 0.7 ± 0.1 L·min-1; p < 0.01), indicative of a greater non-propulsive cost of cycling. These results suggest that differences in efficiency between trained male and female cyclists can be partly accounted for by sex-specific variation in lean leg volume. [ABSTRACT FROM AUTHOR]

The impact of different intensity training on cycling efficiency in competitive cyclists is unknown. Twenty-nine endurance-trained competitive male cyclists completed 3 laboratory visits during a 12-week training period. At each visit, their cycling efficiency and maximal oxygen uptake were determined. After the first visit, cyclists were randomly split into 2 groups (A and B). Over the first 6 weeks, between tests 1 and 2, group A was prescribed specific high-intensity training sessions, whereas group B was restricted in the amount of intensive work undertaken. After test 2 and for the second 6-week period, group B was allowed to conduct high-intensity training. Gross efficiency (GE) increased in group A (+1.6 ± 1.4%; p < 0.05) following the high-intensity training, whereas no significant change was seen in group B (+0.1 ± 0.7%; p > 0.05). Group B cyclists increased their GE between tests 2 and 3 (+1.4 ± 0.8%; p < 0.05) but no changes in GE were observed in group A over this period (+0.4 ± 0.4%; p > 0.05). Delta efficiency (DE) did not change significantly in either group across the study period. This study demonstrates that GE is increased following high-intensity training in competitive male cyclists after 12 weeks. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the impact of a novel crank system on laboratory time-trial cycling performance. The Rotor system makes each pedal independent from the other so that the cranks are no longer fixed at 180°. Twelve male competitive but non-elite cyclists (mean ± s: 35 ± 7 yr, Wmax = 363 ± 38 W, VO2peak = 4.5 ± 0.3 L·min-1) completed 6-weeks of their normal training using either a conventional (CON) or the novel Rotor (ROT) pedal system. All participants then completed two 40.23-km time-trials on an air-braked ergometer, one using CON and one using ROT. Mean performance speeds were not different between trials (CON = 41.7 km·h-1 vs. ROT = 41.6 km·h-1, P > 0.05). Indeed, the pedal system used during the time-trials had no impact on any of the measured variables (power output, cadence, heart rate, VO2, RER, gross efficiency). Furthermore, the ANOVA identified no significant interaction effect between main effects (Time-trial crank system*Training crank system, P > 0.05). To the authors' knowledge, this is the first study to examine the effects of the Rotor system on endurance performance rather than endurance capacity. These results suggest that the Rotor system has no measurable impact on time-trial performance. However, further studies should examine the importance of the Rotor 'regulation point' and the suggestion that the Rotor system has acute ergogenic effects if used infrequently. [ABSTRACT FROM AUTHOR]

The article presents a study aimed at monitoring the training-related changes in gross efficiency (GE) of trained cyclists during the competitive cycling season. Considerations on the subject of the study is provided, in which trained cyclists, during competitive cycling season, underwent laboratory tests for lactate threshold, onset of blood lactate accumulation, maximal minute power and oxygen uptake and GE. Base on the interpretation of the results, the study found changes of GE during the cycling season and GE is related to the intensity of training conducted.

The purpose of this study was to examine the acute effect of talocrural joint position on muscle activity and gross mechanical efficiency (GE). Eleven trained cyclists participated in three randomized 6-min cycling bouts at approximately 80% of maximal aerobic capacity on an electromagnetically braked cycle ergometer while oxygen consumption and muscle activity (EMG) were monitored during the subject's self-selected pedaling technique (control) and while using a dorsi- and plantarflexed pedaling technique. The mean differences in range of motion of the dorsi- and plantarflexed technique from the control position were 7.1 +/- 4.4 and 6.9 +/- 5.4 degrees , respectively. Gastrocnemius EMG activity was higher with the dorsiflexion technique than when using the self-selected control position (33.2 +/- 13.0 and 24.2 +/- 8.4 microV s, respectively; P < 0.05). Moreover, GE was 2.6% lower while riding with the dorsiflexion technique than the control position (19.0 +/- 1.2 and 19.5 +/- 1.3%, respectively; P < 0.05). The data suggested that introducing more dorsiflexion into the pedal stroke of a trained cyclist increases muscle activity of the gastrocnemius lateralis and decreased GE when compared to the self-selected pedal stroke. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the interactions between cadence and power output effects on cycling efficiency. Fourteen healthy subjects performed four constant power output-tests (40, 80, 120 and 160 W) in which the cadence varied in five bouts from 40 to 120 rpm. Gross efficiency (GE) was determined over the last ten respiratory cycles of each bout and was calculated as the ratio of mechanical energy to energy expenditure. Results showed that (1) GE-cadence relationships reached a maximum at each power output corresponding to the cadence maximising efficiency (CAeff) and (2) GE increased with power output whatever the cadence until a maximal theoretical value. Moreover, interactions were found between these two factors: the cadence effect decreased linearly with power output and the power output effect increased exponentially with cadence. Consequently, cycling efficiency decreased more when cadence differed from CAeff at low than at high power output, and increased more with power output at high cadence than at low cadence. These interactions between cadence and power output effects on GE were mainly due to cadence and power output effects on the energy expenditure shares not contributing to power production. [ABSTRACT FROM AUTHOR]

The article presents a study which was conducted to determine the effect of high pedaling cadences on maximal cycling power output. Well-trained cyclist performed a continuous, incremental cycle-ergometer test to exhaustion either at 80, 100, or 120 revolutions per minute on three different occasions. It was concluded that a high pedaling cadence reduces performance and anaerobic threshold during an incremental test in well-trained cyclists. The data suggested that ventilatory anaerobic threshold is a sensitive predictor of optimal pedaling cadence for performance.

This study proposed a non-invasive method to determine the gross (GE, no baseline correction), net (NE, resting metabolism as the baseline correction) and work (WE, unloaded cycling as the baseline correction) efficiencies during cycling at an intensity higher than the maximal aerobic power (MAP). Twelve male subjects performed two exercises consisting of 4 min at 50% MAP followed either by 8 min at 63% MAP or by 8 sequences of 60 s divided into 10 s at 130% MAP and 50 s at 50% MAP (i.e., 63% MAP on average). Oxygen uptake was continuously measured to calculate GE, NE and WE at 50%, 63% and 130% MAP, and the data presented as the means and standard deviations. The GE values were 18.2%, 19.1%, 22.7%, the NE values were 22.4%, 22.8%, 24.3% and the WE values were 34.2%, 31.4% and 27.2% at 50%, 63% and 130% MAP, respectively. The GE and NE increased (P < 0.001) whereas the WE decreased (P < 0.001) with each increment in power output. The GE was lower than the NE (P < 0.001) at 50% and 63% MAP and than the WE (P < 0.001) at all intensities. The NE was lower (P < 0.001) than the WE at 50% and 63% MAP. These results showed that (1) efficiency index values obtained during supra-maximal exercise were consistent with previous proposals and (2) the efficiency-power output relationships were not limited to sub-maximal intensity levels but were confirmed at higher power output. [ABSTRACT FROM AUTHOR]