Cycle-run Transition Research Articles

Running after cycling induces inter-limb differences in muscle activation but not in kinetics or kinematics

ABSTRACT Overuse injuries are a common problem to triathletes’ population. Overuse injuries may arise from inter-limb biomechanical differences during running, but the literature lacks information regarding inter-limb differences in triathletes. In this study inter-limb differences were investigated in injury-free triathletes during the running portion of a simulated cycle-run transition. Thirteen triathletes performed a 5 km run preceded by a 20 min cycling trial at 70% of maximal power output. During the Start, Mid and End stages of running, kinetic, kinematic and muscle activation variables were compared between the preferred and non-preferred limbs across the stance phase. A statistical parametric mapping analysis showed no differences between limbs when considering kinetic and kinematic variables (p > 0.05, ES<0.60). A lower soleus activation was observed in the preferred limb (p < 0.05, ES>0.60) from 53.40–75.9% of the stance phase at the End stage of running. In conclusion, inter-limb differences in kinetic or kinematic variables may not represent a risk for overloading in triathletes. However, inter-limb differences in triceps surae activation during running after cycling may represent one potential factor leading to overuse injuries in triathletes and should be further investigated.

Neuromuscular and physiological variables evolve independently when running immediately after cycling

During the early period of running after cycling, EMG patterns of the leg are modified in only some highly trained triathletes. The majority of studies have analysed muscle EMG patterns at arbitrary, predetermined time points. The purpose of this study was to examine changes to EMG patterns of the lower limb at physiologically determined times during the cycle-run transition period to better investigate neuromuscular adaptations. Six highly trained triathletes completed a 10min isolated run (IR), 30min of rest, then a 20min cycling procedure, before a 10min transition run (C-R). Surface EMG activity of eight lower limb muscles was recorded, normalised and quantified at four time points. Oxygen uptake and heart rate values were also collected. Across all muscles, mean (±SD) EMG patterns, demonstrated significant levels of reproducibility for each participant at all four time points (α<0.05; r=0.52–0.97). Mean EMG patterns during C-R correlated highly with the IR patterns (α<0.05). These results show that EMG patterns during subsequent running are not significantly affected by prior cycling. However, variability of muscle recruitment activity does appear to increase during C-R transition when compared to IR.

Impact of Cycling Intensity on Cycle-run Transition in Female Triathletes

PURPOSE: The purpose of the study was to determine the impact of intensity during the final km of a cycling bout on subsequent run and overall cycle-run (CR) performance. A secondary aim of the study was to examine how manipulations in cycling power affect cycle-run performance in female triathletes exclusively. METHODS: Nine well-trained female triathletes participated in the study. The triathletes completed two CR sessions (20 km cycle, 5 km run). The intensity of the first 19 km of cycling was equivalent to peak power at 70% of peak oxygen consumption (O 2 peak) and the final 1 km varied between power achieved at 95% of O 2 peak (high intensity, HI) and power achieved at 50% of O 2 peak (low intensity, LI). The 5 km run was completed as fast as possible. RESULTS: Mean blood lactate concentration [La - ] was significantly higher during the run following the cycling bout ending with a HI rather than a LI (11.5 ± 0.64 mmol/L vs. 9.3 ± 0.72 mmol/L). Run performance was not significantly different between HI and LI (24:54 ± 02:53 min vs. 00:24:36 ± 00:03:17 min). As well, no significant differences were found between overall CR sessions (01:23:23 h ± 00:05:47 min vs. 01:23:50 h ± 00:07:01 min). CONCLUSION: Despite increases in [La - ], cycling intensity during the final stages of a 20 km cycling bout does not impact run or CR performance in well-trained female triathletes.

Risk factors and injury mechanism in Triathlon

In the triathlon the combined practice of swimming, cycling and running permits the reduction of overuse injuries compared to the practice of the running alone. Redistribution of stress over several part of the body and correction of muscle imbalance are cited as reasons for the reduction in injuries occurrence. Nonetheless, like other endurance sports, 80-85% of triathlon injuries can be scribed to overuse. From an etiopathogenetic point of view the overuse injuries must be studied in relation to the technical characteristics of the triathlon, to the transitional phases between the disciplines and particularly to the cycle-run transition, to the different load of training that the preparation of the Olympic distance requires compared to the long distance triathlon. Most of the injuries are caused by running and athletes most at risk are former swimmers and cyclists, since they lack of running experience and muscle elasticity. The triathlon cycle-run transition (T2) is a period of particular risk for knee and lower back injury. The knee, the ankle/foot and the lower back are the anatomic site most at risk of injuries. Ileotibial band friction syndrome is common in age groupers whereas Achilles tendon injuries and stress fractures occur more in elite athletes. Previous injuries are correlated with injuries occurrence and the sudden changes in training intensity or volume, hill training and the insufficient development of running technical ability are injuries extrinsic factors. The acute traumatology is due almost exclusively to falls in training and competition in cycling. The episodes of rhabdomiolysis are instead not rare, associated or not to exertional heat/idratation injuries. Injury prevention is based in particular on the learning of the correct technique of the three disciplines, on the right programming of the training sessions, on the study of the overload that the biomechanics of the transition phases between the three sports act on the locomotor apparatus and on the suitability of the technical instruments used.

The Effects of Compression Socks on Running Economy Following a Cycle-Run Transition

The Effects of Compression Socks on Running Economy Following a Cycle-Run Transition

The Effect of Cycling Cadence on the Cycle-Run Transition in Triathletes

The Effect of Cycling Cadence on the Cycle - Run Transition in Triathletes PURPOSE: This study investigated the effect of deviating from triathletes' preferred cycling cadence (PC) on triathlon cycle-run transition and 10 km run performance. METHODS: Trained triathletes (N = 12) underwent three Olympic-distance cycle-run trials at race pace. The first (baseline) trial established PC, average power output (PO) and 10 km run time. In the second and third trials, administered in a counter-balanced fashion, cadence was increased (HC) or decreased (LC) cadence by 20% from PC during the last 13 km of the 40 km cycling bout; PO was constant across all bouts. Six physiological variables (heart rate (HR), oxygen consumption (VO2), minute ventilation (VE), respiratory exchange ratio (RER), rating of perceived exertion (RPE) and lactate) were measured at four time points during all trials: 27 - 28 km cycle (Time 1), 38 - 40 km cycle (Time 2), 1 - 8 min run (Time 3) and 8 - 10 km run (Time 4). Run time and physiological variables at Times 1 and 4 over the three trials were each analyzed by one-way ANOVA, whereas physiological variables at Times 2 and 3 (cycle-run transition) were analyzed by 3 x 2 (trial x time) ANOVA with repeated measures on both factors. RESULTS: The cycle-run transition, but not run time, was influenced by cadence manipulation. When comparing HC to LC, HC resulted in a smaller change in energy requirements when transitioning from cycling to running. The LC strategy was more energetically efficient than HC during cycling, but resulted in a greater change in energy requirements during the cycle-run transition. Overall, the HC strategy was more physiologically demanding than the LC trial. CONCLUSION: Triathletes may minimize energy usage during cycling by utilizing a lower than preferred cadence prior to running. In contrast, they may minimize the difference in energy usage between the cycling and running bouts, thus minimizing the cycle-run transition, by utilizing a higher than preferred cadence strategy prior to running.

Impact of seated and standing bicycle riding position on subsequent running performance

This study examined the effects of cycling posture on subsequent running performance similar to the transition phase of a triathlon. Experienced, non-elite triathletes completed two trials of a cycle-run transition. During the last three minutes of a 30 minute cycling bout, at power output equal to lactate threshold, subjects either remained seated (SEAT), or alternated seated and standing cycling (30 s at a time; ALT). Heart rate, RPE, minimum and maximum knee angle, stride frequency and length, and onset and duration of quadriceps and hamstrings activity were obtained at the end of a three-minute control run and at minutes 0, 2, &amp; 4, of running after cycling transition. Repeated Measures ANOVA (condition X minute; p = 0.05) found control was significantly different than minute 0 for stride frequency and length, but not for minimum or maximum knee angle. EMG duration at minute 4 was less than all other time points for both quadriceps and hamstrings. Onset of muscle activity was not different for hamstring or quadriceps. Heart rate and RPE both increased over 15 minutes after transition and were higher for SEAT than ALT, however, there was no interaction (minute by position) for either variable. Results indicated changes in stride rate and length following cycling occur, but disappear within two minutes after the transition to running and do not differ between postures. Changes in duration of muscle activity may be related to changes in stride. Also HR and RPE differ between the SEAT and ALT cycling positions and over time.

Effects of Multicycle-Run Training on Triathlete Performance

The purpose of this study was to determine the effect of triathlon training using multiple, short cycle-run sequences (multicycle-run training) on cycle-run performance. Twelve competitive triathletes, randomized into two groups, underwent multicycle-run training or normal training for 6 weeks. During this period, baseline training remained the same for both groups, and only the high-intensity component differed. The differentiated exercises were performed at or above 100% maximal aerobic velocity. The improvements in overall cycle-run performance were similar (3.3 ± 1.4 % and 6.1 ± 1.7 % rise in performance in multicycle-run and normal training, respectively). However, the improvement in performance was significantly greater for the multicycle-run training (- 11.2 ± 6.8 s versus −1.2 ± 7.7 s for multicycle-run training and normal training, respectively) during both the cycle-run change and the first 333-m lap, which together are termed the cycle-run transition. We concluded that 6 weeks of multicycle-run training did not induce greater improvement in cycle-run performance than did normal training in competitive triathletes. However, it did induce significant improvement in the cycle-run transition. This finding indicates that multicycle-run training may help competitive triathletes to develop greater skill and better physiological adaptations during this critical transition period of the triathlon race.

Catecholamine, blood lactate and ventilatory responses to multi-cycle-run blocks.

This study was designed to determine whether the physiological responses elicited during the run part of repeated bouts of cycle-run exercise are similar to those required during the run segment of a cycle-run succession. Thirteen male triathletes underwent four successive laboratory trials: 1) an incremental treadmill test, 2) an incremental cycle test, 3) 30 min of cycling followed by 20 min of running (C-R), and 4) five repeated bouts of 6 min of cycling and 4 min of running (X-CR). During the C-R and X-CR trials, venous blood samples were obtained to measure lactate, epinephrine and norepinephrine concentrations. During all trials, ventilatory data were collected every min using an automated breath-by-breath system. The results showed that 1) the cardiorespiratory responses observed during running were similar in the X-CR and C-R trials, 2) the lactate concentration was similar in both trials, 3) the epinephrine concentration was greater (277.9 +/- 11.9 vs 169.8 +/- 86.7 pg x mL(-1), P < 0.025) in X-CR than in C-R, and 4) the norepinephrine concentration was similar in both trials, except at the first cycle-run succession (T1) of X-CR. We concluded that 1) multi-block training is a good method to stimulate the specific adaptations required for the cycle-run succession, and particularly for the cycle-run transition, and 2) multi-block training seems to induce a greater catecholaminergic response, which may be due to a combination of an inherent effect of this type of training and the triathletes' relative lack of experience with it. In any case, the efficacy of the multi-block model needs to be more thoroughly evaluated over the course of a longer-term training program.

Ventilatory responses during experimental cycle-run transition in triathletes.

To determine the effects of cycling on a subsequent triathlon run, nine male triathletes underwent four successive laboratory trials: 1) an incremental treadmill test, 2) an incremental cycle test, 3) 30 min of cycling followed by 5 km of running (C-R), and 4) 30 min of running followed by 5 km of running (R-R). Before and 10 min after the third and fourth trials, the triathletes underwent pulmonary function testing including spirometry and diffusing capacity testing for carbon monoxide (DL(CO)). During the C-R and R-R trials, arterialized blood samples were obtained to measure arterial oxygen pressure (PaO2). During all trials, ventilatory data were collected every minute using an automated breath-by-breath system. The results showed that 1) the oxygen uptake (VO2) observed during subsequent running was similar for the C-R and R-R trials; 2) the ventilatory response (VE) during the first 8 min of subsequent running was significantly greater in the C-R than in R-R trial (P < 0.05); 3) only the C-R trial induced a significant increase (P < 0.05) in residual volume (RV), functional residual capacity (FRC), and the ratio of residual volume to total lung capacity (RV/TLC); and 4) although a significant decrease (P < 0.05) in DL(CO) was noted after C-R, no difference between the two exercise trials was found for the maximal drop in PaO2. We concluded that 1) the C-R trial induced specific alterations in pulmonary function that may be associated with respiratory muscle fatigue and/or exercise-induced hypoxemia, and 2) the greater VE observed during the first minute of running after cycling was due to the specificity of cycling. This reinforces the necessity for triathletes to practice multi-trial training to stimulate the physiological responses experienced during the swim-cycle and the cycle-run transitions.

Ventilatory specificities of the cycle-run transition in triathletes

Ventilatory specificities of the cycle-run transition in triathletes