Mid Sweden University

Introduction: Biathlon combines cross country skiing and rifle marksmanship, and the athletes need to carry the rifle (mass >3.5 kg) on their back during skiing. Previous research in laboratory settings have shown that physiological variables, i.e. heart rate (HR), oxygen uptake (VO2), ventilation (VE), breathing frequency (BF), respiratory exchange ratio (RER) and blood lactate concentration (BLa) increases when roller-skiing with rifle (WR) at submaximal workloads compared to roller-skiing without rifle (NR) (1, 2). Roller-skiing performance is also shown to decrease for WR compared to NR during laboratory testing (1). Purpose: The aim was to investigate the effect of rifle carriage on performance and physiological variables during a simulated biathlon roller-skiing sprint in the field.Methods: 20 well-trained tier 3 (3) biathletes (10 women, 10 men; age 22±3 years) completed two biathlon roller-skiing sprints (women 3×2km; men 3×2.5km) in the field, one WR and one NR in a randomized order, separated by 30 minutes of active rest. After each lap, the athlete stopped for 30–45 s (normal shooting time) for measurement of BLa and rating of perceived exertion (RPE, 6–20). Respiratory variables and HR were measured throughout the sprints. A two-way repeated measurements ANOVA (two conditions (WR/NR) × three laps) was used to compare performance and physiological variables between conditions. During the stops, WR and NR was compared using paired samples t-test. Wilcoxon Signed Rank test was used if data was non-normally distributed. Data are presented as mean±SD, except for RPE (presented as median (IQR)).Results: Mean roller-skiing speed for the race was 0.20 m/s slower for WR compared to NR (5.5±0.5 vs. 5.7±0.5 m/s, p<0.001). The time loss during WR was 13.5±14.6, 12.2±8.7 and 16.9±9.6 s for laps 1, 2, and 3, respectively. No difference between WR and NR in mean HR, O2, VE, BF, RER or BLa was found for any of the skiing laps (all p>0.05). However, RPE, mean VO2, VE and BF during the second stop (simulating standing shooting) was higher for WR compared to NR (RPE 18 (1) vs 17 (1), p = 0.008; VO2 40±5 vs 37±4 ml/kg/min, p=0.006; VE 99±23 vs 92±18 L/min, p=0.031; BF 52±6 vs. 48±4 breaths/min, p=0.005) with no difference in the duration of the stop (p>0.05). Conclusion: Unlike previous laboratory studies, this field-based study demonstrates that respiratory variables, HR and BLa were similar for WR and NR during roller-skiing, despite the higher skiing speed for NR during all the three laps. However, respiratory variables and RPE were higher during the second stop for WR, which may impact shooting performance. To replicate competition demands, biathletes are advised to carry their rifle during high-intensity training sessions that include shooting.

1. Jonsson Kårström et. al (2019) doi: 10.3389/fphys.2019.015192. Stöggl et. al (2015) doi: 10.1249/mss.00000000000004383. McKay et. al (2022) doi: 10.1123/ijspp.2021-0451

Purpose: To compare the frequency and severity of self-perceived negative symptoms associated with the menstrual cycle or hormonal-contraceptive (HC) cycle between (1) HC users and non–HC users and (2) different competition levels. An additional aim was to describe the rate and type of HC use and prevalence of potential menstrual-cycle disturbances in female team handball players. Methods: A total of 136 team handball players, competing at different levels (international, 48; national, 52; local/regional, 36), completed a cross-sectional survey regarding self-reported negative cycle-related symptom frequency and severity, perceived influence on training/competition performance, menstrual function, and current and/or past HC use. Results: Although most players regularly experienced negative cycle-related symptoms, non–HC users reported more frequent and severe cramps (P = .001 to .026), as well as a higher occurrence of fatigue and skin problems (P = .019 to .045), compared with HC users. Negative symptoms such as fatigue were more common and severe for local/regional-level players compared with players at higher (international) competition levels (P = .006–.046). Half (47%) of the players currently used HC, primarily long-acting reversible contraceptives (52%), as well as the combined oral (33%) or progestin-only pill (14%). Notably, only 2% of players altered their training in response to negative cycle-related symptoms, despite 41% perceiving that these symptoms interfered with training quality and athletic performance. Conclusions: Negative cycle-related symptoms are common among team handball players, regardless of HC use, and are perceived by many players to adversely influence their athletic performance. 

This longitudinal study investigated 1) differences in self-reported cycle-related symptom severity and recovery measures (sleep quality, readiness to train, resting heart rate) between pre-bleeding, bleeding, and non-bleeding days in athletes using/not using hormonal contraception (HC); 2) associations between symptom severity and recovery measures. Fifty-eight female endurance athletes recorded recovery measures, perceived symptom severity, and menstruation/withdrawal (bleeding) days for one year. Athletes were grouped as: intrauterine system (IUS)-, implant-, progestin-only oral contraceptive (POC)-, combined oral contraceptive (COC)- and non-HC users. All groups reported higher symptom severity during bleeding compared to pre-bleeding and non-bleeding days (both p <.001), while implant users reported less severe symptoms than IUS (p <.001) and non-HC users (p =.008). Perceived sleep quality was lower during pre-bleeding compared to bleeding days (p <.001) for all groups. However, IUS users reported higher sleep quality (p =.039) and physical readiness-to-train (p =.010) than non-HC users. Symptom severity was negatively associated with sleep quality and physical readiness-to-train (both p <.050). Pre-bleeding days and cycle-related symptom severity were found to negatively influence self-reported recovery measures in both HC- and non-HC users. Therefore, athletes and their support staff are advised to prioritize symptom management and the adjustment of recovery strategies on an individual basis throughout the athletes’ cycles. 

Introduction: Power profiling is widely used in cycling performance analysis, but both absolute and mass-normalized power outputs have limitations as performance indicators, as they neglect external factors such as terrain, wind, aerodynamic drag, and pacing strategy. To address these limitations, this study introduced a numerical method to quantify how external forces acting on the cyclist influence the conversion of power output into race velocity. Thus, the study aimed to enable accurate prediction of cycling performance based on estimated mean power output over complex time-trial courses. Methods: Time-trial performances of five elite-level road cyclist profiles—a sprinter, climber, all-rounder, general classification (GC) contender, and a time trialist—were estimated using the power-duration relationship and previously published normative data. These performance estimates were applied to both simplified hypothetical courses and complex real-world time-trial courses. Optimal mass exponents for the power-to-mass ratio were determined based on the estimated average speeds over the respective course sections, cyclist morphology, and external factors such as gradient and wind velocity. Results: Across two recent Grand Tour individual time-trial courses, stage 21 of the 2024 Tour de France and stage 7 of the 2024 Giro d’Italia, the duration-weighted optimally mass-normalized power output metrics were (Formula presented.) and (Formula presented.), respectively. These metrics accurately predicted the estimated performances of the five defined cyclist profiles ((Formula presented.) for both). Discussion: The results indicate that the duration-weighted optimal mass exponents for the power-to-mass ratio are course-specific. By deriving optimal mass exponents across various modeled courses and wind conditions, the study was able to precisely quantify the influence of road gradient, headwind speed, and bicycle mass on the conversion of power output relative to body mass into speed. Further research is needed to validate the presented method for determining optimal mass exponents in real-world performance settings. 

The aims of the current study were to (1) report the prevalence of hormonal contraceptive (HC) use among Norwegian women across different training categories and age groups; (2) compare the frequency and severity of cycle-related symptoms across differing training categories and age groups; and (3) describe the bleeding pattern and prevalence of menstrual disorder/disturbances among non-HC users. A sample of 2059 Norwegian women completed a survey reporting: weekly training volume; current HC usage, type, and reasons for use; cycle-related symptom frequency and severity; and the prevalence of menstrual disorders/disturbances. Respondents were categorized by age (youth: 13–20; young adults: 21–30; older adults: 31–50 years) and training category (minimal: 0; low: < 5; moderate: 5–9; high: ≥ 9 h·week−1). Half (51.6%) of respondents reported current HC usage, predominantly long-acting reversible contraception or combined oral contraceptives. Young adults had the highest prevalence of HC use (62.7%) compared to youth (48.4%) and older adults (43.8%), although no differences in usage were seen across training categories. HC users reported fewer and less severe cycle-related symptoms compared to non-users. A third (30.8%) of non-HC users had experienced a menstrual disorder/disturbance, with no significant differences observed across training categories or age groups. In conclusion, HC use is widespread among Norwegian women, with no differences between training categories. This similar HC prevalence suggests that HC research conducted in female cohorts may be generalizable, independent of training category. However, attention should be paid to participants' age due to differences in HC use between age groups. 

Objectives: This study assessed the test–retest reliability of athletic performance tests in a cohort of trained Norwegian female handball players, as well as a sub-analysis of the test–retest reliability for naturally menstruating players. Design: Eighteen handball players (naturally menstruating: n = 8) completed performance test batteries on three separate occasions. Methods: The performance test battery included: a 1-repetition Smith machine back squat, maximal handgrip strength tests, counter-movement jumps, squat jumps, a modified agility T-test, and 15-m linear sprints. For the naturally menstruating players, the testing sessions were completed at three hormonally-distinct points within a menstrual cycle (i.e., early follicular, ovulation, and mid-luteal phases). Reliability statistics (intraclass correlations, standard error of measurement, minimum difference, and coefficient of variation) were calculated for each performance test. Results: Good-to-excellent test–retest reliability was found for all performance measures (intraclass correlation2,1 point estimates = 0.82 to 0.94), although max squat jumps were somewhat lower (intraclass correlation2,1 = 0.75 [95 % confidence interval = 0.55, 0.88]). Subgroup analysis for naturally menstruating players also revealed consistently high reliability values for all tests (intraclass correlation2,1 point estimate = 0.83 to 0.74). Conclusions: These reliability data support the periodic use of selected athletic tests in routine handball assessments, in order to identify changes in sporting performance and monitor player progress. As test reliability does not appear to be influenced by the menstrual cycle phase, coaches and sports practitioners may schedule testing sessions for all athletes, without concern of a confounding effect from menstrual phases. 

Purpose: To describe and compare the annual physical training characteristics between Norwegian female cross-country (XC) skiers and biathletes across competition levels and age categories. Methods: Daily training sessions for 1 year were recorded for 45 XC skiers and 26 biathletes, comprising international/national team (inter[national]) and nonnational/regional team members (nonnational) of both junior and senior age. Endurance, strength, flexibility, speed, and power training sessions were recorded. Data included exercise modality, intensity, and duration. Data were analyzed using linear mixed-effects models. Results: The total annual physical training volume consisted of -90% endurance training for both groups, although XC skiers had significantly higher total volumes (-10%; P = .003; d= 0.78) than biathletes. Senior XC skiers performed more training hours of skiing and/or roller skiing compared with biathletes over the season. However, biathletes compensated for this lower volume by more skating and a higher proportion of endurance training as skiing (81% [17%]) compared with XC skiers (68% [16%]; P < .001; d= 0.94). Overall, (inter)national-level athletes completed a higher annual training volume than non-national-level athletes (740 [90] h vs 649 [95] h; P= .004;d = 0.81). Although juniors reported less endurance volume than seniors, they maintained a relatively stable level of endurance training across the preparatory and competition period, unlike senior athletes. Conclusions: The higher annual physical training volume by XC skiers compared with biathletes is likely caused by the different demands of the 2 sports; XC skiing necessitates training for 2 skiing styles, while biathlon requires additional shooting practice. However, biathletes compensate with a higher proportion of ski training, particularly in the skating technique.

Female athletes frequently perceive performance changes throughout the menstrual cycle (MC). However, if and how the MC influences performance-determining variables remain unclear.PurposeThis study aimed to investigate the effect of the MC and endogenous sex hormone concentrations on performance-determining variables in three distinct MC phases in endurance-trained females.MethodsTwenty-one eumenorrheic trained/highly trained endurance athletes completed a standardized test battery during the early follicular phase (EFP), ovulatory phase (OP), and midluteal phase (MLP) for either one (n = 7) or two test cycles (n = 14). MC phases were determined using calendar-based counting, urinary ovulation testing, and verified with serum hormone analysis. MCs were retrospectively classified as eumenorrheic or disturbed. Disturbed MCs were excluded from analysis. The test battery consisted of 4-6 x 5-min submaximal stages with stepwise speed increases, a 30-s all-out double-poling ski ergometer test, and a maximal incremental treadmill running test.ResultsAt a group level, there was no effect of MC phase or the serum concentrations of estrogen and progesterone on peak oxygen uptake (VO2peak), oxygen uptake at 4 mmol<middle dot>L-1 blood lactate concentration, time to exhaustion, running economy, or mean 30-s power output (MPO30s). Serum testosterone concentration was positively associated with MPO30s (P = 0.016). Changes in VO2peak from EFP to MLP were inconsistent between individuals and across cycles.ConclusionsNone of the measured performance-determining variables were influenced by MC phase or serum estrogen or progesterone concentrations. Although some individual patterns could be observed, there was no indication that any single MC phase is consistently associated with improved or impaired VO2peak on a group level.

Purpose: To identify differences in heart rate (HR) and concentration of blood lactate ([La]) relationships between laboratory and field-based skate-roller-skiing tests.

Methods: Fourteen world-class biathletes (8 women, 6 men) completed a laboratory- and field-based roller-skiing test using the skate technique. The laboratory-based test comprised 5 to 7 submaximal steps at a fixed incline and speed on a roller-skiing treadmill. The field-based test comprised 5 steps on a course where the final hill was designed to mimic the conditions of the laboratory test. HR and [La] were measured for each step. The HR associated with 2 mmol·L−1(HR@2 mmol) and 4 mmol·L−1 (HR@4 mmol) of [La] was calculated using an interpolation method. A 1-way analysis of variance and Bland–Altman analyses with 95% limits of agreement (LoA) were used to determine if test type influenced HR@2 mmol orHR@4 mmol. A second-order polynomial was fitted to group-level data to highlight the HR–[La] relationships for laboratory- and field-based tests.

Results: HR@2 mmol was lower for field tests than for laboratory tests (mean bias: 1.9%HRmax; 95% LoA: −4.5 to+8.3%HRmax; P < .001). HR@4 mmol was also lower for field tests compared to laboratory tests (mean bias: 2.4%HRmax; 95%LoA: −1.2 to +6.0%HRmax; P < .001). On the group level, the lactate threshold occurred at a lower HR during roller skiing in the field compared to the laboratory.

Conclusions: The findings from this study confirm that for a given HR, [La] was greater in field compared with laboratory-based conditions. These results might have implications for how coaches define training-intensity“zones” during skate roller skiing based on laboratory tests.

Purpose: To compare physiological responses between a self-paced 4-min double-poling (DP) time-trial (TTDP) versus a 4-min diagonal-stride (DS) time-trial (TTDS). The relative importance of peak oxygen uptake (V ˙ O2peak), anaerobic capacity, and gross efficiency (GE) for projection of 4-min TTDP and TTDS roller-skiing performances were also examined. Methods: Sixteen highly trained male cross-country skiers performed, in each sub-technique on separate occasions, an 8 × 4-min incremental submaximal protocol, to assess individual metabolic rate (MR) versus power output (PO) relationships, followed by a 10-min passive break and then the TTDP or TTDS, with a randomized order between sub-techniques. Results: In comparison to TTDS, the TTDP resulted in 10 ± 7% lower total MR, 5 ± 4% lower aerobic MR, 30 ± 37% lower anaerobic MR, and 4.7 ± 1.2 percentage points lower GE, which resulted in a 32 ± 4% lower PO (all P &lt; 0.01). The V ˙ O2peak and anaerobic capacity were 4 ± 4% and 30 ± 37% lower, respectively, in DP than DS (both P &lt; 0.01). The PO for the two time-trial (TT) performances were not significantly correlated (R 2 = 0.044). Similar parabolic pacing strategies were used during both TTs. Multivariate data analysis projected TT performance using V ˙ O2peak, anaerobic capacity, and GE (TTDP, R 2 = 0.974; TTDS, R 2 = 0.848). The variable influence on projection values for V ˙ O2peak, anaerobic capacity, and GE were for TTDP, 1.12 ± 0.60, 1.01 ± 0.72, and 0.83 ± 0.38, respectively, and TTDS, 1.22 ± 0.35, 0.93 ± 0.44, and 0.75 ± 0.19, respectively. Conclusions: The results show that a cross-country skier’s “metabolic profile” and performance capability are highly sub-technique specific and that 4-min TT performance is differentiated by physiological factors, such as V ˙ O2peak, anaerobic capacity, and GE.