Case Studies in Physiology: Maximal oxygen consumption and performance in a centenarian cyclist

The purpose of this study was to examine the physiological characteristics of an elite centenarian cyclist who, at 101 yr old, established the 1-h cycling record for individuals ≥100 yr old (24.25 km) and to determine the physiological factors associated with his performance improvement 2 yr later at 103 yr old (26.92 km; +11%). Before each record, he performed an incremental test on a cycling ergometer. For 2 yr, he trained 5,000 km/yr with a polarized training that involved cycling 80% of mileage at “light” rate of perceived exertion (RPE) ≤12 and 20% at “hard” RPE ≥15 at a cadence between 50 and 70 rpm. His body weight and lean body mass did not change, while his maximal oxygen consumption (V̇o2max) increased (31–35 ml·kg−1·min−1; +13%). Peak power output increased from 90 to 125 W (+39%), mainly because of increasing the maximal pedaling frequency (69–90 rpm; +30%). Maximal heart rate did not change (134–137 beats/min) in contrast to the maximal ventilation (57–70 l/min, +23%), increasing with both the respiratory frequency (38–41 cycles/min; +8%) and the tidal volume (1.5–1.7 liters; +13%). Respiratory exchange ratio increased (1.03–1.14) to the same extent as tolerance to V̇co2. In conclusion, it is possible to increase performance and V̇o2max with polarized training focusing on a high pedaling cadence even after turning 100 yr old. NEW & NOTEWORTHY This study shows, for the first time, that maximal oxygen consumption (+13%) and performance (+11%) can still be increased between 101 and 103 yr old with 2 yr of training and that a centenarian is able, at 103 yr old, to cover 26.9 km/h in 1 h.

Time-frequency analysis of heart rate variability reveals cardiolocomotor coupling during dynamic cycling exercise in humans

To test the hypothesis that cycling exercise modulates heart rate variability (HRV), we applied a short-time Fourier transform on the electrocardiogram of subjects performing a maximal graded cycling test. A pedaling frequency component (PFC) in HRV was continuously observed over the time course of the exercise test and extracted from R-R interval series obtained from 15 healthy subjects with a heterogeneous physical fitness, exercising at three different pedaling frequency ( n = 5): 70, 80, and 90 rpm. From 30 to 50% of the maximal power output (Pmax), in the 90 rpm group, spectral aliasing caused PFC to overlap with the respiratory sinus arrhythmia (RSA) band, significantly overestimating the PFC amplitude ( APFC). In the meantime, APFC did not increase significantly from its minimal values in the 70 rpm (∼1.26 ms) and 80 rpm (∼1.20 ms) groups. Then, from 60 to 100% maximal power output (Pmax), workload increase caused a significant ∼2.8-, ∼3.3-, and ∼3.4-fold increase in APFC in the 70, 80, and 90 rpm groups, respectively, with no significant difference between groups. At peak exercise, APFC accounted for ∼43, ∼39, and ∼49% of the total HRV in the 70, 80, and 90 rpm groups, respectively. Our findings indicate that cycling continuously modulates the cardiac chronotropic response to exercise, inducing a new component in HRV, and that workload increase during intense exercise further accentuates this cardiolocomotor coupling. Moreover, because PFC and RSA overlapped at low workloads, methodological care should be taken in future studies aiming to quantify RSA as an index of parasympathetic activity.

Some Observations on Human Control of a Bicycle

The purpose of this study is to identify human control actions in normal bicycling. The task under study is the stabilization of the mostly unstable lateral motion of the bicycle-rider system. This is done by visual observation of the rider and measuring the vehicle motions. The observations show that very little upper-body lean occurs and that stabilization is done by steering control actions only. However, at very low forward speed a second control is introduced to the system: knee movement. Moreover, all control actions are performed at the pedaling frequency, whilst the amplitude of the steering motion increases rapidly with decreasing forward speed.

Does Prior 1500-m Swimming Affect Cycling Energy Expenditure in Well-Trained Triathletes?

The purpose of this study was to determine the effects of a 1,500-m swim on energy expenditure during a subsequent cycle task. Eight well-trained male triathletes (age 26.0 ± 5.0 yrs; height 179.6 ± 4.5 cm; mass 71.3 ± 5.8 kg; [Formula: see text] 71.9 ± 7.8 ml kg−1•min−1) underwent two testing sessions in counterbalanced order. The sessions consisted of a 30-min ride on the cycle ergometer at 75% of maximal aerobic power (MAP), and at a pedaling frequency of 95 rev•min−1, preceded either by a 1,500-m swim at 1.20 m•s−1 (SC trial) or by a cycling warm-up at 30% of MAP (C trial). Respiratory and metabolic data were collected between the 3rd and the 5th min, and between the 28th and 30th min of cycling. The main results indicated a significantly lower gross efficiency (13.0%) and significantly higher blood lactate concentration (56.4%), [Formula: see text] (5.0%), HR (9.3%), [Formula: see text] (15.7%), and RF (19.9%) in the SC compared to the C trial after 5 min, p < 0.05. After 30 min, only [Formula: see text] (7.9%) and blood lactate concentration (43.9%) were significantly higher in the SC compared to the C trial, p < 0.05. These results confirm the increase in energy cost previously observed during sprint-distance triathlons and point to the importance of the relative intensity of swimming on energy demand during subsequent cycling. Key words: lactate, oxygen uptake, intensity, exercise duration, performance

Determinants of increased energy cost of submaximal exercise in obese subjects

The energy cost of submaximal cycling exercises is studied in 23 obese (OS) and 13 lean control (LS) subjects at 1) a constant pedaling frequency (60 rpm) and at various work loads [external work loads (Wmec) up to 100 W] for one group of OS and LS, and at 2) constant Wmec (brake free and 60 or 70 W) and various frequencies (38–70 rpm) for a second group of OS and LS. The total energy expenditure (WO2) is calculated from O2 consumption (VO2) measured in both conditions and is compared with anthropometric data. The results show that at rest or at the same Wmec, WO2 is always greater in OS than in LS. At rest the quotients of WO2 over body surface area are not significantly different. At work the difference in WO2 cannot be explained by the muscular mechanical efficiency, which is not statistically different in OS (26 +/- 7.8%) and LS (25 +/- 4.6%). The calculated increase in the work of breathing of OS can account only for 5–15% of the energy overexpenditure. The energy cost of leg movement is estimated in brake-free cycling trials; it is significantly greater in OS than in LS (118 J compared with 68 J/pedal stroke), but when divided by leg volume the figures are not different (9.2 compared with 8.5 J X dm-3 X pedal stroke-1). Leg moving may account for approximately 60–70% of the energy cost of moderate exercise in cycling OS. The remaining difference in WO2 between OS and LS (20–30%) may be explained by an increase in muscular postural activity related to the lack of physical training of OS.

Effects of glycogen depletion and pedaling speed on "anaerobic threshold"

Nine male subjects performed continuous incremental exercise on a bicycle ergometer pedaling at 50 and 90 rpm in a normal glycogen state (NG) and at 50 rpm in a glycogen-depleted state (GD) to determine if alterations in pedaling frequency and muscle glycogen content would affect their “anaerobic thresholds.” Ventilatory [T(vent)] and lactate [T(lac)] thresholds were identified as the points after which expired minute volume and blood lactate began to increase nonlinearly as a function of work rate. The GD protocol elicited a significant divergence between the two thresholds shifting the T(vent) to a lesser and the T(lac) to a greater work rate relative to the NG state. When the pedaling frequency was increased to 90 rpm in the NG condition, the T(lac) was shifted to a lesser work rate relative to the 50-rpm NG condition. A correlation of only 0.71 was obtained between subjects' T(vent) and T(lac). In subjects of less than 70 kg body wt, the T(lac) came at a work rate 400 kg.m.min-1 less than in subjects of greater than 80 kg body wt despite equivalent O2 uptake. The observation that the T(vent) and T(lac) could be manipulated independently of each other reveals limitations in using the T(vent) to estimate the so-called anaerobic threshold.