Maximal aerobic and anaerobic power and time performance in 800 m double poling ergometer.

The purpose of this study was to investigate to what extent aerobic power (MAP), maximal anaerobic power (MANP), anaerobic capacity measured as time to exhaustion at 130% MAP (TTE), and maximal accumulated oxygen deficit (MAOD) correlated with 800 m double poling time trial performance (800TT) in a ski ergometer. A second aim was to investigate the relationship between TTE and MAOD, and to what extent TTE and MAOD would relate to anaerobic power reserve (APR). Eighteen cross-country skiers were tested for peak oxygen uptake (VO2peak) and oxygen cost of double poling to assess MAP. Peak power measurements during a 100 m TT were performed to assess MANP. TTE and an 800TT with continuous VO2 measurements were performed to assess time performance and MAOD. All tests were performed on a ski ergometer. Both MAP and MANP correlated strongly (r = - 0.936 and - 0.922, respectively, p < 0.01) with 800TT. Neither TTE nor MAOD correlated with 800TT. TTE correlated moderately with MAOD, both in mL kg-1 and in %VO2peak (r = 0.559, p < 0.05 and 0.621, p < 0.01, respectively). Both TTE and MAOD seemed to be a product of APR. These results suggest focusing on MAP and MANP, but not anaerobic capacity to explain time performance in an event with approximately 3 min duration.

Relationships Between Maximal Aerobic Speed, Lactate Threshold, and Double Poling Velocity at Lactate Threshold in Cross-Country Skiers.

Purpose: To investigate the relationships between maximal aerobic speed (MAS), lactate threshold in per cent of peak oxygen uptake (LT) and velocity at LT (LTv) in cross-country skiers. Secondly, we aimed to explore the fit of an equation previously used in cyclists and runners in a cohort of well-trained, competitive cross-country skiers for calculation of LTv. Thirdly, we aimed to investigate if a new LTv could still be calculated after a period of regular training only by providing a new MAS. Methods: Ninety-five competitive cross-country skiers (65 males and 30 females) were tested for maximal oxygen uptake (VO2max), peak oxygen uptake in double poling (DP-VO2peak), oxygen cost of double poling (CDP), LT, and LTv. Thirty-five skiers volunteered to be tested 3 months later to evaluate potential changes in LT and LTv. Results: Velocity at LT was mainly determined by MAS (r = 0.88, p < 0.01). LT did not show a significant impact on LTv. The product of MAS·LT precisely predicted LTv at baseline (r = 0.99, SEE = 2.4%), and by only measuring MAS, a new LTv could be accurately calculated (r = 0.92, SEE = 6.8%) 3 months later in a sub-set of the initial 95 skiers (n = 35). Conclusion: The results suggest that LT has minor impact on LTv in DP tested in a laboratory. LTv seemed to be predominantly determined by MAS, and we suggest to put more focus on MAS and less on LT and LTv in regular testing to evaluate aerobic performance capacity in DP.

Effects of Individual Changes in Training Distribution on Maximal Aerobic Capacity in Well-Trained Cross-Country Skiers: A Follow-Up Study.

The purpose of this study was to evaluate individual changes in training distribution and the subsequent effects on maximal oxygen uptake (VO2max). The participants were well-trained cross-country skiers who had performed a year with no substantial changes in training prior to this study. Six cross-country skiers, who were participants in a larger previous study, volunteered for a follow-up study. All skiers performed self-motivated changes in training distribution for a new preparation period in this follow-up, generally by more high-intensity training (HIT). All training characteristics were registered from training diaries. During the follow-up period, all skiers performed an incremental VO2max test in February 2020 and August 2020. Training were categorized into three different training periods; (1) February 2019 to February 2020 (P 1) representing the training performed prior to the follow-up, (2) February 2020 to July 2020 (P 2), and (3) July 2020 to August 2020 (P 3). On average, the skiers increased their VO2max by 5.8 ± 5.0% (range: -1.8 to + 10.2%) during the follow-up study compared with the average VO2max during the preceding year. Total training volume increased on average by 10.0 and 25.7% in P 2 and P 3, respectively, compared with P 1. The average volume of HIT was similar between P 1 and P 2 but increased 62.8% in P 3. However, large individual differences in training changes were observed. In conclusion, the present study revealed that individual changes in training distribution generated an increased VO2max in four out of six already well-trained cross-country skiers. Reduced total training volume (three out of six) and increased (four out of six) HIT volume were the most marked changes.

Steeper or Faster? Tactical Dispositions to Minimize Oxygen Cost in Ski Mountaineering.

PURPOSE: Investigate the effect of speed, inclination, and use of heel elevator on the oxygen cost of vertical climbing (Cvert) in ski mountaineering. METHODS: In this study, 19 participants who were (3 women and 16 men) moderate- to well-trained recreational Norwegian ski mountaineers were involved. All participants were tested for VO2max in running, and in a ski mountaineering test on a treadmill, to assess Cvert. The test protocol consisted of 12 4 min work periods at different inclinations from 13 to 23°, with continuous VO2 measurements. After every second work period, the inclination increased by 2°, and speed was decreased accordingly. The speed reduction was based on the equation Vvert = speed · sin(α), where α represents the angle of inclination. Vvert was thus held constant for each work period (854 m·h-1). All work periods were completed twice, with and without a heel elevator. Half of the subjects started with the smallest inclination, and the other half started with the steepest inclination. RESULTS: The results showed that Cvert was unchanged at all inclinations except 13°, where there was a significantly higher Cvert, at the same Vvert. Only at 13°, Cvert was higher with the use of heel elevator. There was also a significant trend indicating lower Cvert with use of heel elevator with steeper inclination. CONCLUSIONS: There seemed to be nothing to gain by choosing detours if the inclination was 13° or less. The use of heel elevator was more advantageous, the steeper the inclination, but at 13° there was a negative effect of using heel elevator.

Improving Utilization of Maximal Oxygen Uptake and Work Economy in Recreational Cross-Country Skiers With High-Intensity Double-Poling Intervals.

PURPOSE: To investigate the effect of a double-poling (DP) high-intensity aerobic interval-training (HIT) intervention performed without increasing total HIT volume. This means that regular HIT training (eg, running) was replaced by HIT DP. The aim was to explore whether this intervention could improve peak oxygen uptake in DP, the fractional utilization of maximal oxygen uptake (VO2max) in DP, oxygen cost of DP, maximal aerobic speed, and a 3-km DP time trial. METHODS: Nine non-specially-DP-trained cross-country skiers (intervention group) and 9 national-level cross-country skiers (control group) were recruited. All participants were tested for VO2max in running, peak oxygen uptake in DP, oxygen cost of DP, and time-trial performance before and after a 6-wk, 3-times-per-week HIT DP intervention. The intervention group omitted all regular HIT with HIT in DP, leaving the total weekly amount of HIT unchanged. RESULTS: Seven participants in each group completed the study. VO2max in running remained unchanged in both groups, whereas peak oxygen uptake in DP improved by 7.1% (P = .005) in the intervention group. The fractional utilization of VO2max in DP thus increased by 7.3% (P = .019), oxygen cost of DP by 9.2% (P = .047), maximal aerobic speed by 16.5% (P = .009), and time trial by 19.5% (P = .004) in the intervention group but remained unchanged in the control group. CONCLUSIONS: The results indicate that a 6-wk HIT DP intervention could be an effective model to improve DP-specific capacities, with maintenance of VO2max in running.

No Change - No Gain; The Effect of Age, Sex, Selected Genes and Training on Physiological and Performance Adaptations in Cross-Country Skiing.

The aim was to investigate the effect of training, sex, age and selected genes on physiological and performance variables and adaptations before, and during 6 months of training in well-trained cross-country skiers. National-level cross-country skiers were recruited for a 6 months observational study (pre - post 1 - post 2 test). All participants were tested in an outside double poling time trial (TTDP), maximal oxygen uptake in running (RUN-VO2max), peak oxygen uptake in double poling (DP-VO2peak), lactate threshold (LT) and oxygen cost of double poling (CDP), jump height and maximal strength (1RM) in half squat and pull-down. Blood samples were drawn to genetically screen the participants for the ACTN3 R577X, ACE I/D, PPARGC1A rs8192678, PPARG rs1801282, PPARA rs4253778, ACSL1 rs6552828, and IL6 rs1474347 polymorphisms. The skiers were instructed to train according to their own training programs and report all training in training diaries based on heart rate measures from May to October. 29 skiers completed all testing and registered their training sufficiently throughout the study period. At pre-test, significant sex and age differences were observed in TTDP (p < 0.01), DP-VO2peak (p < 0.01), CDP (p < 0.05), MAS (p < 0.01), LTv (p < 0.01), 1RM half squat (p < 0.01), and 1RM pull-down (p < 0.01). For sex, there was also a significant difference in RUN-VO2max (p < 0.01). No major differences were detected in physiological or performance variables based on genotypes. Total training volume ranged from 357.5 to 1056.8 min per week between participants, with a training intensity distribution of 90-5-5% in low-, moderate- and high-intensity training, respectively. Total training volume and ski-specific training increased significantly (p < 0.05) throughout the study period for the whole group, while the training intensity distribution was maintained. No physiological or performance variables improved during the 6 months of training for the whole group. No differences were observed in training progression or training adaptation between sexes or age-groups. In conclusion, sex and age affected physiological and performance variables, with only a minor impact from selected genes, at baseline. However, minor to no effect of sex, age, selected genes or the participants training were shown on training adaptations. Increased total training volume did not affect physiological and performance variables.

Stronger Is Better: The Impact of Upper Body Strength in Double Poling Performance.

The purpose of the present study was to compare time results from a roller-skiing double poling (DP) time trial with different physiological variables, muscular strength variables, and DP characteristics in both male and female young competitive skiers with the same relative training background. In order to do this, 28 (16 women and 12 men) well-trained 16-25-year-old cross-country skiers from three Norwegian high schools for skiers, as well as local high performance competitive skiers from the South-East of Norway were recruited to participate in the study. All participants were tested for; maximal oxygen uptake in running, Peak oxygen uptake in DP, lactate threshold in DP, DP economy, time to voluntary exhaustion in DP, force analyses in DP, one repetition maximum and power output in pulldown, and leg press and a time trial during DP roller skiing. The results expressed strong correlations between roller skiing time trial performance and maximal strength in pull-down, both independent (r xy = -0.83, p < 0.01) and dependent (r xy-z = -0.50, p < 0.02) of sex. Higher maximal upper body strength was related to higher DP peak forces (PF) (r xy = 0.78, p < 0.02), lower DP frequency (r xy = -0.71, p < 0.01), and shorter DP contact time (CT) (r xy = -0.48, p < 0.02). The practical implications of the present study is to acknowledge maximal upper body strength as a performance determining factor in DP. This point at the importance of including maximal strength training in cross-country skiers training programs.

A time-saving method to assess power output at lactate threshold in well-trained and elite cyclists.

The purpose of this study was to examine the relationship between lactate threshold (LT) as a percentage of maximal oxygen consumption (V[Combining Dot Above]O2max) and power output at LT (LTW) and also to investigate to what extent V[Combining Dot Above]O2max, oxygen cost of cycling (CC), and maximal aerobic power (MAP) determine LTW in cycling to develop a new time-saving model for testing LTW. To do this, 108 male competitive cyclists with an average V[Combining Dot Above]O2max of 65.2 ± 7.4 ml·kg·min and an average LTW of 274 ± 43 W were tested for V[Combining Dot Above]O2max, LT %V[Combining Dot Above]O2max, LTW, MAP, and CC on a test ergometer cycle. The product of MAP and individual LT in %V[Combining Dot Above]O2max was found to be a good determinant of LTW (R = 0.98, p < 0.0001). However, LT in %V[Combining Dot Above]O2max was found to be a poor determinant of LTW (R = 0.39, p < 0.0001). Based on these findings, we have suggested a new time-saving method for calculating LTW in well-trained cyclists. The benefits from this model come both from tracking LTW during training interventions and from regularly assessing training status in competitive cyclists. Briefly, this method is based on the present findings that LTW depends on LT in %V[Combining Dot Above]O2max, V[Combining Dot Above]O2max, and CC and may after an initial test session reduce the time for the subsequent testing of LTW by as much as 50% without the need for blood samples.

Maximal strength training improves cycling economy in competitive cyclists.

The purpose of the present study was to investigate the effect of maximal strength training on cycling economy (CE) at 70% of maximal oxygen consumption (Vo2max), work efficiency in cycling at 70% Vo2max, and time to exhaustion at maximal aerobic power. Responses in 1 repetition maximum (1RM) and rate of force development (RFD) in half-squats, Vo2max, CE, work efficiency, and time to exhaustion at maximal aerobic power were examined. Sixteen competitive road cyclists (12 men and 4 women) were randomly assigned into either an intervention or a control group. Thirteen (10 men and 3 women) cyclists completed the study. The intervention group (7 men and 1 woman) performed half-squats, 4 sets of 4 repetitions maximum, 3 times per week for 8 weeks, as a supplement to their normal endurance training. The control group continued their normal endurance training during the same period. The intervention manifested significant (p < 0.05) improvements in 1RM (14.2%), RFD (16.7%), CE (4.8%), work efficiency (4.7%), and time to exhaustion at pre-intervention maximal aerobic power (17.2%). No changes were found in Vo2max or body weight. The control group exhibited an improvement in work efficiency (1.4%), but this improvement was significantly (p < 0.05) smaller than that in the intervention group. No changes from pre- to postvalues in any of the other parameters were apparent in the control group. In conclusion, maximal strength training for 8 weeks improved CE and efficiency and increased time to exhaustion at maximal aerobic power among competitive road cyclists, without change in maximal oxygen uptake, cadence, or body weight. Based on the results from the present study, we advise cyclists to include maximal strength training in their training programs.

Short-term effects of strength and plyometric training on sprint and jump performance in professional soccer players.

The purpose of this study was to compare the effects of combined strength and plyometric training with strength training alone on power-related measurements in professional soccer players. Subjects in the intervention team were randomly divided into 2 groups. Group ST (n = 6) performed heavy strength training twice a week for 7 weeks in addition to 6 to 8 soccer sessions a week. Group ST+P (n = 8) performed a plyometric training program in addition to the same training as the ST group. The control group (n = 7) performed 6 to 8 soccer sessions a week. Pretests and posttests were 1 repetition maximum (1RM) half squat, countermovement jump (CMJ), squat jump (SJ), 4-bounce test (4BT), peak power in half squat with 20 kg, 35 kg, and 50 kg (PP20, PP35, and PP50, respectively), sprint acceleration, peak sprint velocity, and total time on 40-m sprint. There were no significant differences between the ST+P group and ST group. Thus, the groups were pooled into 1 intervention group. The intervention group significantly improved in all measurements except CMJ, while the control group showed significant improvements only in PP20. There was a significant difference in relative improvement between the intervention group and control group in 1RM half squat, 4BT, and SJ. However, a significant difference between groups was not observed in PP20, PP35, sprint acceleration, peak sprinting velocity, and total time on 40-m sprint. The results suggest that there are no significant performance-enhancing effects of combining strength and plyometric training in professional soccer players concurrently performing 6 to 8 soccer sessions a week compared to strength training alone. However, heavy strength training leads to significant gains in strength and power-related measurements in professional soccer players.