Assessment of bike handling during cycling individual time trials with a novel analytical technique adapted from motorcycle racing

A methodology to study bike handling of cyclists during individual time trials (ITT) is presented. Lateral and longitudinal accelerations were estimated from GPS data of professional cyclists (n=53) racing in two ITT of different length and technical content. Acceleration points were plotted on a plot (g-g diagram) and they were enclosed in an ellipse. A correlation analysis was conducted between the area of the ellipse and the final ITT ranking. It was hypothesized that a larger area was associated to a better performance. An analytical model for the bike-cyclist system dynamics was used to conduct a parametric analysis on the influence of riding position on the shape of the g-g diagram. A moderate (n=27, r=-0.40, p=0.038) and a very large (n=26, r=-0.83, p<0.0001) association were found between the area of the enclosing ellipse and the final ranking in the two ITT. Interestingly, this association was larger in the shorter race with higher technical content. The analytical model suggested that maximal decelerations are highly influenced by the cycling position, road slope and speed. This investigation, for the first time, explores a novel methodology that can provide insights into bike handling, a large unexplored area of cycling performance.

Alternate-Day Low Energy Availability During Spring Classics in Professional Cyclists

PURPOSE

To assess energy and carbohydrate (CHO) availability and changes in blood hormones in 6 professional male cyclists over multiple single-day races.

METHODS

The authors collected weighed-food records, power-meter data, and morning body mass measurements across 8 d. CHO intakes were compared with contemporary guidelines. Energy availability (EA) was calculated as energy intake minus exercise energy expenditure, relative to fat-free mass (FFM). Skinfold thickness and blood metabolic and reproductive hormones were measured prestudy and poststudy. Statistical significance was defined as P ≤ .05.

RESULTS

Body mass (P = .11) or skinfold thickness (P = .75) did not change across time, despite alternate-day low EA (14 [9] vs 57 [10] kcal·kg-1 FFM·d-1, race vs rest days, respectively; P < .001). Cyclists with extremely low EA on race days (<10 kcal·kg-1 FFM·d-1; n = 2) experienced a trend toward decreased testosterone (-14%) and insulin-like growth factor 1 (-25%), despite being high EA (>46 kcal·kg-1 FFM·d-1) on days between. CHO intakes were significantly higher on race versus rest days (10.7 [1.3] vs 6.4 [0.8] g·kg-1·d-1, respectively; P < .001). The cyclists reached contemporary prerace fueling targets (3.4 [0.7] g·kg-1·3 h-1 CHO; P = .24), while the execution of CHO guidelines during race (51 [9] g·h-1; P = .048) and within acute (1.6 [0.5] g·kg-1·3 h-1; P = .002) and prolonged (7.4 [1.0] g·kg-1·24 h-1; P = .002) postrace recovery was poor.

CONCLUSIONS

The authors are the first to report the day-by-day periodization of energy and CHO in a small sample of professional cyclists. They also examined the logistics of conducting a field study under stressful conditions in which major cooperation from the subjects and team management is needed. Their commentary around these challenges and possible solutions is a major novelty of the article.

Ketone Diester Ingestion Impairs Time-Trial Performance in Professional Cyclists

We investigated the effect of pre- “race” ingestion of a 1,3-butanediol acetoacetate diester on blood ketone concentration, substrate metabolism and performance of a cycling time trial (TT) in professional cyclists. In a randomized cross-over design, 10 elite male cyclists completed a ~31 km laboratory-based TT on a cycling ergometer programmed to simulate the 2017 World Road Cycling Championships course. Cyclists consumed a standardized meal [2 g/kg body mass (BM) carbohydrate (CHO)] the evening prior to a trial day and a CHO breakfast (2 g/kg BM CHO) with 200 mg caffeine on the morning of a trial day. Cyclists were randomized to consume either the ketone diester (2 × 250 mg/kg) or a placebo drink, followed immediately by 200 mL diet cola, given ~ 30 min before and immediately prior to commencing a 20 min incremental warm-up. Blood samples were collected prior to and during the warm-up, pre- and post- TT and at regular intervals after the TT. Urine samples were collected pre- and post- warm-up, immediately post TT and 60 min post TT. Pre-exercise ingestion of the diester resulted in a 2 ± 1% impairment in TT performance that was associated with gut discomfort and higher perception of effort. Serum β-hydroxybutyrate, serum acetoacetate, and urine ketone concentrations increased from rest following ketone ingestion and were higher than placebo throughout the trial. Ketone ingestion induces hyperketonemia in elite professional cyclists when in a carbohydrate fed state, and impairs performance of a cycling TT lasting ~50 min.

Physical Demands of Sprinting in Professional Road Cycling

The aim of this study was to quantify the demands of road competitions ending with sprints in male professional cycling. 17 races finished with top-5 results from 6 male road professional cyclists (age, 27.0±3.8 years; height, 1.76±0.03 m; weight, 71.7±1.1 kg) were analysed. SRM power meters were used to monitor power output, cadence and speed. Data were averaged over the entire race, different durations prior to the sprint (60, 10, 5 and 1 min) and during the actual sprint. Variations in power during the final 10 min of the race were quantified using exposure variation analysis. This observational study was conducted in the field to maximize the ecological validity of the results. Power, cadence and speed were statistically different between various phases of the race (p<0.001), increasing from 316±43 W, 95±4 rpm and 50.5±3.3 km·h(-1) in the last 10 min, to 487±58 W, 102±6 rpm and 55.4±4.7 km·h(-1) in the last min prior to the sprint. Peak power during the sprint was 17.4±1.7 W·kg(-1). Exposure variation analysis revealed a significantly greater number of short-duration high-intensity efforts in the final 5 min of the race, compared with the penultimate 5 min (p=0.010). These findings quantify the power output requirements associated with high-level sprinting in men's professional road cycling and highlight the need for both aerobic and anaerobic fitness.