Use of planar covariation in lower limb kinematics to characterize adaptations of running after cycling in elite triathletes.

Purpose: To characterize alterations of lower limb intersegmental coordination during the acute phase of running after cycling among highly trained triathletes using an analysis of planar covariation. Methods: Nine highly trained triathletes completed a control run (CR) and a run after transitioning from cycling exercise (transition run, or TR condition) on a motorized treadmill at a self-selected pace. Sagittal plane kinematics were recorded using a 3D Vicon motion capture system. Intersegmental coordination of the thigh, shank and foot segments of the right lower limb and run loop planarity were calculated during running before cycling and at four different times after the end of cycling. Results: PCA showed a significant within-subject phase shift of the run loop planarity (F = 6.66, P = 0.01). Post hoc analysis showed significance median differences increase for u 3t parameter between CRSS vs. TR30 (P = 0.01), TRt1/2 (P = 0.01) and TRMRT (P = 0.01). No difference for u 3t parameter existed between CRSS vs. TRSS. Conclusion: Prior variable-cadence, moderate intensity cycling has a significant effect on run loop planarity and therefore intersegmental coordination during the acute transition phase among highly trained triathletes. However, alterations to lower limb coordination are corrected by the 3rd minute after the beginning of the post cycle run. We suggest that planar covariation can be used as a more sensitive measure of cycling-induced variations in running to characterize adaptation in elite and importantly, developing athletes.

Is Moderate Intensity Cycling Sufficient to Induce Cardiorespiratory and Biomechanical Modifications of Subsequent Running?

Walsh, JA, Dawber, JP, Lepers, R, Brown, M, and Stapley, PJ. Is moderate intensity cycling sufficient to induce cardiorespiratory and biomechanical modifications of subsequent running? J Strength Cond Res 31(4): 1078-1086, 2017-This study sought to determine whether prior moderate intensity cycling is sufficient to influence the cardiorespiratory and biomechanical responses during subsequent running. Cardiorespiratory and biomechanical variables measured after moderate intensity cycling were compared with control running at the same intensity. Eight highly trained, competitive triathletes completed 2 separate exercise tests; (a) a 10-minute control run (no prior cycling) and, (b) a 30-minute transition run (TR) (preceded by 20-minute of variable cadence cycling, i.e., run versus cycle-run). Respiratory, breathing frequency (fb), heart rate (HR), cost of running (Cr), rate constant, stride length, and stride frequency variables were recorded, normalized, and quantified at the mean response time (MRT), third minute, 10th minute (steady state), and overall for the control run (CR) and TR. Cost of running increased (p ≤ 0.05) at all respective times during the TR. The V[Combining Dot Above]E/V[Combining Dot Above]CO2 and respiratory exchange ratio (RER) were significantly (p < 0.01) elevated at the MRT and 10th minute of the TR. Furthermore, overall mean increases were recorded for Cr, V[Combining Dot Above]E, V[Combining Dot Above]E/V[Combining Dot Above]CO2, RER, fb (p < 0.01), and HR (p ≤ 0.05) during the TR. Rate constant values for oxygen uptake were significantly different between CR and TR (0.48 ± 0.04 vs. 0.89 ± 0.15; p < 0.01). Stride length decreased across all recorded points during the TR (p ≤ 0.05) and stride frequency increased at the MRT and 3 minutes (p < 0.01). The findings suggest that at moderate intensity, prior cycling influences the cardiorespiratory response during subsequent running. Furthermore, prior cycling seems to have a sustained effect on the Cr during subsequent running.

Comparative effectiveness of 5-fluorouracil with and without oxaliplatin in the treatment of colorectal cancer in clinical practice.

BACKGROUND: First-line chemotherapeutic treatment of colorectal cancer (CRC) typically comprises oral (capecitabine) or intravenous 5-fluorouracil (5-FU) plus leucovorin (LV), in combination with oxaliplatin (XELOX or FOLFOX, respectively), although debate exists regarding the best course of treatment by modality in clinical practice. Evidence from practice comparisons is important in considering the net benefit of alternative chemotherapy regimens, given expected differences in survival associated with compliance and age of patients treated in real life versus controlled trial settings. PATIENTS AND METHODS: Practice variation in 5-FU treatment (i.e. 5-FU/leucovorin, FOLFOX, capecitabine and XELOX) of patients with CRC from an Australian area health service (n=636) was analyzed between modalities by patient age, tumour stage and site using non-parametric tests. Survival analyses (n=434) were conducted over a three-year follow-up period using Cox regression, adjusting for observed confounders. RESULTS: FOLFOX was the most commonly administered regimen. 5-FU modality was significantly associated with patient age (p<0.001), tumour stage (p<0.001) and site (p<0.001). Cox regression analyses found no significant difference in survival with the addition of oxaliplatin to 5-FU regimens. CONCLUSION: Our findings suggested no survival benefit with the addition of oxaliplatin to 5-FU modalities in treating CRC in practice. This raises questions as to the net benefit of oxaliplatin, given its known toxicity profile and expense.