ECSS Paris 2023: OP-AP15
INTRODUCTION: To organize training into shorter periods of time with specific training focuses has become increasingly common for endurance athletes in recent years. Particularly, organizing high-intensity interval training sessions in microcycles has been well-studied and found to improve endurance performance-related variables [1]. There is, however, little evidence on how efficient similar type of training strategy is when performing moderate-intensity interval training (MIT) in well-trained endurance athletes. Here, we compare the physiological effects of a seven-day MIT microcycle with a time-matched period with usual training (CON) in well-trained cyclists. METHODS: Using a randomized crossover design, 30 male cyclists (maximal oxygen consumption (VO2max),70.5 (4.6) mL/min/kg) performed both a MIT microcycle and CON training. Sixteen and 14 of them started with the MIT microcycle and CON training, respectively. The MIT microcycle consisted of six interval sessions distributed over seven days. In consecutive days, except for a rest day on the 4th day, they performed interval sessions with 7x10 min, 6x12 min, 5x14 min, 7x10 min, 5x14 min, and 6x12 min work periods, with the aim of hitting 14-15 on the Borg 6-20 rating of perceived exertion (RPE) during the work intervals (equivalent to a perceived exertion of “somewhat hard” to “hard”). A six-day taper period was carried out before physiological testing. The efficacy of the MIT and CON training was measured as changes in 15-min maximal average power output (PO15min), power output at 4 mmol/L [blood lactate] (PO4mmol), mean power output achieved during the last minute of an incremental test (pVO2max), and VO2max. RESULTS: Average RPE during work intervals in the MIT microcycle was 14.4 (0.3), which corresponded to 66.4 (4.8) % of pVO2max, 85.3 (3.3) % of maximal heart rate, and 2.8 (1.1) mmol/L [blood lactate]. The MIT microcycle led to significantly larger improvements than CON on PO4mmol (4.0 (4.4) % vs. -1.3 (3.7) %, respectively; p<0.001) and pVO2max (2.5 (4.5) % vs. -0.7 (3.9) %, respectively; p=0.007), while changes in PO15min were not statistically different between interventions (3.9 (8.3) % vs. 0.2 (6.8) %, respectively; p=0.138). VO2max tended to increase more following MIT than CON (2.0 (3.9) % vs 0.0 (3.5) %, respectively; p=0.055). CONCLUSION: Six MIT sessions distributed over seven days followed by a taper period induced larger improvements in measures of endurance performance than a time-matched period of usual training in well-trained cyclists. Reference: 1. Mølmen KS, Øfsteng SJ, Rønnestad BR. Block periodization of endurance training - a systematic review and meta-analysis. Open access J Sport Med. 2019;10:145–60.
Read CV Knut Sindre MølmenECSS Paris 2023: OP-AP15
INTRODUCTION: Typically, low intensity endurance exercise (LIE) is performed as a continuous session below the first lactate threshold. However, this is not the only way to execute LIE. High intensity micro-intervals, which should not be confused with maximal sprint interval exercises, are exercises, where work phase lasts at most 15 seconds at ~100% VO2max and recovery period is at least twice as long. These intervals mimic LIE metabolically and cardiopulmonarily [1]. The energy during micro-intervals is produced aerobically using oxygen from the myoglobin stores [1, 2]. Therefore, micro-intervals are highly promising stimulus for peripheral aerobic adaptations, as well as for neuromuscular system adaptations, as muscles operates at or near 100% VO2max with minimal anaerobic component and metabolic cost. However, little is known about the feasibility and usability of such intervals in the long-term training. The aim of the present study was to investigate whether high-level cyclists’ LIE can be replaced with high intensity micro-intervals. METHODS: In this quantitative-qualitative pilot study, three national-level cyclists (one female) progressively replaced majority of their LIE with micro-intervals for 10 weeks. They underwent a VO2max test and a 6-minute time trial before and after the intervention. To monitor the stressfulness of the training, they completed total quality recovery -scale [3] each morning. Finally, they were interviewed immediately after the intervention. RESULTS: During the 10-week intervention, the cyclists accumulated 12.5–14.0 h (9–14% of all training time) above VO2max intensity, which accounted for 65–99% of the amount they accumulated during the entire year prior. The cyclists became accustomed to micro-intervals and reported neither cumulative fatigue nor a decrease in total quality recovery. 6-min time trial improved 12–27 W (3–7%), while there were no changes in VO2max. CONCLUSION: A novel finding was that the extensive use of high intensity micro-intervals is a feasible method for athletes; Micro-intervals do not induce excessive fatigue, they allow athletes to accumulate a large amount of high intensity time, and they provide positive performance adaptations. However, the optimal way to include micro-intervals into training and their role in training programming still need thorough examination. [1] Åstrand I, et al. Myohemoglobin as an Oxygen‐Store in Man. Acta Physiol Scand. 1960;48(3–4):454–60. [2] Saltin B & Essen B. Muscle glycogen, lactate, ATP, and CP in intermittent exercise. 1971 [3] Kenttä G & Hassmén P. Overtraining and Recovery A Conceptual Model. Sports Medicine. 1998;26(1):1–16.
Read CV Pekka MatomäkiECSS Paris 2023: OP-AP15
INTRODUCTION: The glycolytic system supports the metabolic energy requirements during intense exercise. The formula of maximal glycolytic rate (Mader’s model) is considered the delta lactate between maximal blood lactate accumulation after a 10-15 s exercise and resting blood lactate levels are divided by the difference between the total exercise time and phosphagen system-contributed time (tPCr). However, this formula does not subtract the energy contribution of oxidative metabolism. Furthermore, tPCr is assumed in which no lactate production takes place (“fictitiously”) although it is well known that lactate production occurs independently of oxygen availability under anoxic, hypoxic, and normoxic conditions. The point of −3.5% from the peak power output (tPCr −3.5%) was utilised in previous studies without providing an in-depth explanation on why the decreased 3.5% time point of the peak power output was used as tPCr. However, this method was based on an error in the early SRM cycle ergometer. Therefore, we modified the limitations of the previous formula and compared different calculations of the maximal glycolytic rate. METHODS: Calculations of the maximal glycolytic rate were based on the differences in defining the phosphagen-contributed time and incorporating the oxidative energy system contribution. In different calculations of the maximal glycolytic rate, tPCr −3.5%, tPCr−peak (the time until peak power output using the latest SRM cycle ergometer [± 0.5-1% error]), and incorporation of the oxidative energy system contribution for pure maximal glycolytic rate using the analysis of the PCr-La−-O2 method during a 15-s maximal cycling test were used. RESULTS: The level of maximal glycolytic rate (tPCr −3.5%) was higher than pure maximal glycolytic rate and maximal glycolytic rate (tPCr−peak) while maximal glycolytic rate (tPCr−peak) was lower than pure maximal glycolytic rate (p < 0.0001, respectively). A very high association between pure maximal glycolytic rate and maximal glycolytic rate (tPCr−peak) was observed (r = 0.99). This association was higher than the relationship between pure maximal glycolytic rate and maximal glycolytic rate (tPCr −3.5%) (r = 0.87). CONCLUSION: Pure maximal glycolytic rate as a novel calculation of maximal glycolytic rate provides more detailed insights into inter-individual differences in energy and glycolytic demands than other calculations of maximal glycolytic rate (tPCr−peak and tPCr −3.5%). In particular, because oxidative and phosphagen contributions can differ remarkably between elite track cyclists, implementing those values in pure maximal glycolytic rate can establish more optimized individual responses for elite track cyclists.
Read CV Woo-Hwi YangECSS Paris 2023: OP-AP15