Mid Sweden University

PURPOSE: To investigate the effect of rifle carriage on performance, physiological responses, power output and external work during a simulated biathlon competition in the field. METHODS: Twenty well-trained biathletes (10 women) completed a simulated biathlon competition (women 3 × 1.9 km, men 3 × 2.4 km) twice, one trial while carrying the rifle (WR) and the other without rifle (NR) in a randomized counter-balanced order. Laps were separated by two simulated shootings, lasting 38.9 ± 8.2 s. Trials were separated by 30-min of active recovery. Heart rate and respiratory variables were measured throughout each trial. Furthermore, blood lactate concentration and ratings of perceived exertion were assessed after each lap. Power output and external work were estimated for both trials based on positional data. RESULTS: , p < 0.001), with largest differences during the uphill sections. No differences in physiological responses were found between WR and NR during laps or course sections (p > 0.05), but oxygen uptake and breathing frequency were higher WR than NR during the second simulated shooting (p < 0.05). Mean power output was slightly lower WR than NR; however, the participants performed more external work WR compared to NR due to the longer duration of the WR trial (both p < 0.05). CONCLUSION: Since elevated physiological markers may negatively impact standing shooting performance, biathletes should optimize their pacing strategies to maximize overall performance. In addition, rifle carriage increases external work through a lengthened skiing duration, which should be considered when planning and performing biathlon training. 

Background

Physical activity is essential for preventing noncommunicable diseases and improving health parameters. However, individuals with intellectual disabilities often struggle to meet recommended activity levels. Sustainable solutions and long-term follow-up are crucial for evaluating intervention efficacy.

Methods

This mixed-method longitudinal follow-up study examines the effects and experiences of a 12-week web-based exercise programme on individuals with intellectual disabilities (ID). Body composition, physical activity levels and waist circumference were measured before and after the 12-week intervention period as well as 12 months after the end of the intervention period (i.e., long-term follow-up). Experiences were analysed using semistructured interviews. In the data analysis, repeated measures ANOVA with Bonferroni correction was utilised to investigate changes over time.

Results

No significant changes were observed after 12 months, but there were effects on postintervention compared with preintervention on waist circumference. Some participants reported experiencing health benefits, which contributed to motivation, while others lacked motivation and were unaware that they could continue to exercise.

Conclusions

While improvements were noted post-intervention, sustaining these gains proved challenging during long-term follow-up. This study highlights the potential of web-based exercise programmes to support individuals with ID in increasing physical activity levels. However, the findings also underscore the need for more tailored and sustainable interventions, including structured support and ongoing engagement strategies, to enable lasting health behaviour change over time.

Background Physical activity is essential for health and well-being during adolescence, and active behaviour early in life predicts higher physical activity levels in adulthood. Although adolescents with intellectual disability (ID) consistently show lower activity levels than peers without ID, national environments—such as school structures, disability support systems, and access to inclusive leisure activities—may influence these patterns. There is limited evidence from Sweden, a country with distinct educational and support frameworks for youth with ID. The present study aimed to examine physical activity patterns among Swedish adolescents with and without ID using accelerometer data. Methods Physical activity was measured objectively using hip-worn accelerometers (ActiGraph GT3X) over seven consecutive days. This cross-sectional study included 45 adolescents with mild-to-moderate ID (median [IQR], 17.0 [14.0–19.0] years; 45.2% females) and 70 adolescents without ID (16.0 [15.0-16.3] years; 62.2% females). Physical activity was categorised as sedentary behaviour (SB), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) and analysed across school days, weekend days, and separately for daytime and evening periods on school days. Results Overall, the relative amount of SB was similar between groups (p > 0.05), but significant differences were observed for LPA and MVPA. Adolescents with ID accumulated more LPA during school-day daytime hours (23% vs. 19%; p = 0.012), while peers without ID accumulated more MVPA during leisure time, such as school-day evenings (p = 0.025) and weekends (p = 0.039). For both groups, MVPA was higher on school days than on weekends (p < 0.001). Among adolescents with ID, SB increased markedly on weekends (72% vs. 77%; p < 0.001). Conclusion Adolescents with ID were generally less physically active than peers without ID, except during schoolday daytime, where the MVPA was similar and LPA was higher. Leisure time, particularly weekends and schoolday evenings, seems to be a critical period in achieving sufficient MVPA among adolescents with ID. Targeted interventions and coordinated support from key stakeholders such as school health services, paediatric health care, social care services and organised sports, with a particular focus on unstructured time, may help promote active lifestyles and reduce health disparities in this population.

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. 

Introduction This study aimed to develop a methodology for establishing the power-duration relationship in cross-country skiers and to investigate the influence of incline on critical power ( C P ) model parameters.Methods Twelve trained male cross-country skiers performed four constant work-rate predictive trials on a motor-driven treadmill, using the double poling sub-technique, to determine their power-duration relationships at 2 degrees and 8 degrees inclines in a randomized order. The testing protocol also included maximum speed tests performed at both inclines. Power-duration relationships were modeled using a modified expression of the three-parameter critical power model.Results The derived power-duration relationships were significantly different between the two inclines. At an 8 degrees incline, the estimated work capacity above C P (i.e., W ' ) was more than two times higher than at a 2 degrees incline ( 24.87 +/- 8.75 kJ vs. 7.07 +/- 1.61 kJ, respectively; Z = 3.06 , P = 0.002 , r r b = 0.88 ), which was partly explained by an increased anaerobic power capacity (i.e., P a n = 4.82 +/- 0.64 W & sdot; kg-1 vs. 1.67 +/- 0.34 W & sdot; kg-1, respectively; Z = 3.06 , P = 0.002 , r r b = 0.88 ). Although C P estimates differed by approximately 16 % between the two inclines on a group level ( 2.78 +/- 0.22 W & sdot; kg-1 vs. 2.39 +/- 0.74 W & sdot; kg-1 at a 2 degrees and at an 8 degrees incline, respectively), a moderate non-significant effect of incline was observed with large individual variances ( Z = 1.88 , P = 0.06 , r r b = 0.54 ). The incline had a non-significant effect on the time constant parameter estimates ( Z = 1.57 , P = 0.12 , r r b = 0.45 ), yet inter-individual variation remained considerable.Discussion The findings demonstrate that in cross-country skiing, both W ' and P a n are highly incline-dependent, showing markedly higher values at steeper gradients. Moreover, the variability observed in C P and W ' across inclines exceeded the typical sensitivity of these parameters to external factors reported in cycling. A large proportion of the incline-related changes in model parameters could be explained by accounting for the estimated variations in gross efficiency across speeds and inclines. However, the persistence of a significant difference in W ' even when expressed in terms of estimated metabolic power at steeper inclines suggests the involvement of additional physiological mechanisms, potentially a larger amount of recruited muscle mass due to differences in muscle fiber recruitment between conditions.

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.