Boye Welde

• Dr. Philos
• Researcher at Norwegian Institute of Public Health

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 disturbance...

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 measure...

Positive associations between physical activity and bone health have been found in population-based studies, however, mostly based on self-reported physical activity. Therefore, we investigated the association between accelerometer-measured physical activity, measured in steps per day and minutes of moderate to vigorous physical activity (MVPA) per...

Female athletes frequently perceive performance changes throughout the menstrual cycle (MC). However, if and how the MC influences performance-determining variables remains unclear. Purpose To investigate the effect of the MC and endogenous sex hormone concentrations on performance-determining variables in three distinct MC phases in endurance-tra...

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 non...

Background Current knowledge about the relationship between physical activity (PA) and cardiac remodeling is mainly derived from cross-sectional studies of athletes, and there is a knowledge gap of this association in the general adult and elderly population. Therefore, we aimed to explore the longitudinal association between cumulative PA and chan...

Purpose To investigate the prevalence of hormonal contraceptive (HC) use by female cross-country (XC) skiers and biathletes competing at a national and/or international level, their reasons for HC use, and to compare negative symptoms related to the HC-/menstrual cycle in HC users and non-HC users. Additionally, to characterize the self-perceived i...

The aim of this study was to examine how relationships between exercise intensity and the rate of energy release established in different ways, affect the calculated O2 deficit accumulated during strenuous exercise. Aerobic energy release is readily measured by the O2 uptake, while anaerobic energy release is by definition independent of O2. The la...

Aims The aim was to investigate the long-term association between leisure time physical activity and hip areal bone mineral density (aBMD), in addition to change in hip aBMD over time, in 32–86 years old women and men. Methods Data were retrieved from the 2001, 2007–2008, and 2015–2016 surveys of the Tromsø Study, a longitudinal population study i...

Studies on females’ decisive physical components to physical match‐play performance are sparse and only emphasize endurance tests. Thus, the influence of maximal strength and power on physical performance during match‐play is currently unknown. The aim of this study was to assess the association between one repetition maximum (1RM) half squat stren...

Whereas left atrial (LA) enlargement is an independent predictor for adverse cardiovascular events and all-cause mortality, this is regarded a physiological adaption of exercise. Paradoxically, LA size in athletes may overlap the enlargement observed in patients with cardiac pathology. Current knowledge is mainly derived from studies of athletes, a...

Introduction: The COVID-19 outbreak with partial lockdown has inevitably led to an alteration in training routines for football players worldwide. Thus, coaches had to face with the novel challenge of minimizing the potential decline in fitness during this period of training disruption. Methods: In this observational pre-to posttest study involving...

Background High load (HL: > 85% of one repetition maximum (1RM)) squats with maximal intended velocity contractions (MIVC) combined with football sessions can be considered a relevant and time-efficient practice for maintaining and improving high velocity movements in football. Flywheel (FW) resistance exercise (RE) have recently emerged with promi...

International Journal of Exercise Science 13(3): X-Y, 2020. This study investigated the acute post-exercise hypotension (PEH) response in persons with elevated blood pressure or stage 1 hypertension following moderate and high-intensity isoenergetic endurance exercise. Twelve middle-aged persons (six females), with resting systolic and diastolic BP...

The aim of this study was to investigate the effect of prolonged ski racing using skating style on technique choice in a transition section among female and male high-level skiers. Fifty three national-to-elite level skiers (20 females: 26.7 ± 4.8 years, 167.0 ± 6.5 m, 61.0 ± 5.1 kg, and 75.5 ± 68.8 FIS points; 33 males: 25.2 ± 3.5 years, 179.0 ± 5...

The aim was to describe longitudinal trends in peak oxygen uptake (VO2peak) among 14- to 19-year-old adolescents in Norway, and to examine effects of sex, body mass index (BMI), and physical activity (PA) level on VO2peak during adolescence. Of 124 invited students from two lower secondary schools in Norway, 116 eighth-grade students (61 boys and 5...

Introduction Long-distance cross-country skiing (XCS) has gained increased popularity within the past decades. However, research about long-distance XCS is limited; therefore, the aim of this study was to analyze the intensity distribution, technique application, and pacing strategies during long-distance XCS racing. Methods Heart rate (HR) and se...

Background: Changes of direction (COD) repeated sprints (RSs) might have greater relevance to football than linear RSs. We aimed to compare the effects of linear and COD RSs on intermittent high intensity running (HIR) over an entire season. Methods: In total, 19 high-level male football players (16-19 years) randomly performed linear RSs or COD...

This randomized within‐subjects crossover‐designed study evaluated intra‐arterial blood pressure (BP) traits in seven healthy males (24 ± 1 years) during heavy resistance exercise (HRE) to failure (10 × 5 repetitions, 5RES) and not to failure (10 × 3 repetitions, 3RES), both at 5RM load. By combining few repetitions, avoidance of Valsalva maneuver,...

The benefits of using longer than self-selected poles have been shown in double poling, but these potential benefits have not been examined in the gear 3 ski skating sub-technique (G3), during which the poling movement is very similar to double poling. The aim of this study was to examine the effect of longer than self-selected poles on physiologic...

Biomechanical differences in double poling (DP) between sex and performance level were investigated in female and male crosscountry skiers during a classical race (10/15 km). Skiers were divided into faster and slower on basis of race performance: females faster (n=20), females slower (n=20), males faster (n=20), and males slower (n=20). Based on v...

Longer distance cross-country ski (14-220 km) races such as the Visma Ski Classics (VSC) has recently gained attention in addition to the traditional Olympic distances (5-50 km) associated with cross-country (XC) skiing. These long-distance races are characterized by extensive use of the upper body while double poling (DP). While there is a substan...

Background The aim of this study was to compare the effect of different soccer-specific maximal actions (Continuous run, Sprint, Sprint with change of direction [Sprint COD], Jump and Shot) upon physiological (oxygen uptake and heart rate) and perceptual (rating of perceived exertion [RPE]) responses and accelerometer load. Materials and methods T...

Here, female and male elite cross-country (XC) skiers were compared on varying terrain during an official 10-km (women) and 15-km (men) Norwegian championship race. On the basis of race performance, 82 skiers were classified as fast (FS) (20 women, 20 men) or slower (SS) (21, 21) skiers. All were video recorded on flat (0°), intermediate (3.5°), up...

This study compared the effects of long (4×4 min) and short intervals (4×8×20 s) of high-intensity interval exercise bouts (HIIT) on running performance, physiological and perceptual responses, and excess postexercise oxygen consumption (EPOC). Twelve healthy college students (8 men, 4 women; mean age=22±2 years) performed long (90–95% of peak hear...

INTRODUCTION: Cross-country skiing (XCS) has been studied extensively, and is unique due to its high demands for endurance capacity and complex regulation and fluctuation of oxygen delivery for both upper and lower body (Holmberg et al., 2007). The Visma Ski Classics (VSC) merges the most traditional long distance XCS events (14-90 km) in Europe an...

In this study the pacing strategy, cycle characteristics and choice of technique of elite male cross-country (XC) skiers during a three-lap, 15-km classical race with interval start were measured. During the Norwegian Championships in 2016, fast (n = 18, age: 26±4 yr; height: 182±4 cm; body mass: 78±3 kg (means±SD)) and slow skiers (n = 18, age: 22...

This study compared the effects of adding upper-body sprint-intervals or continuous double poling endurance training to the normal training on maximal upper-body strength and endurance capacity in female cross-country skiers. In total, 17 female skiers (age: 18.1±0.8yr, body mass: 60±7 kg, maximal oxygen uptake (VO2max): 3.30±0.37 L.min⁻¹) performe...

Supporting data. (XLSX)

Maximal oxygen uptake (VO2max) is regarded as the most performance-differentiating physiological measure in cross-country (XC) skiing. In addition, upper-body strength and lean mass have been associated with double poling (DP) power in XC skiers. In this study, we tested upper-body maximal strength, lean mass and VO2max’s contributions to predict D...

Affiliations: 1Department of Sport and Physical Education, Nord-Trøndelag University College, Levanger, Norway 2Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway 3Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway Introduction: Sprint interval...

The aims of the study were twofold: (a) to investigate how school size affects absentee rates in physical education (PE) and (b) to examine the experiences of students and teachers at a small rural high school in relation to attendance in PE at their school. The absentee rates in PE among all students (N = 6928 students) in a county in Norway were...

In the current study, we evaluated the impact of exercise intensity on gender differences in upper-body poling among cross-country skiers, as well as the associated differences in aerobic capacity, maximal strength, body composition, technique and extent of training. Eight male and eight female elite skiers, gender-matched for level of performance...

To study performance, physiological and biomechanical responses during repeated upper-body sprint exercise. Twelve male elite cross-country skiers performed eight 8-s maximal poling sprints with a 22-s recovery while sitting on a modified SkiErg poling ergometer. Force, movement velocity, cycle rate, work per cycle, oxygen saturation in working mus...

Introduction Upper-body strength and endurance capacity is of high importance for cross-country skiing performance and especially relevant in the double poling movement. This study aimed to investigate how maximal strength in the elbow, shoulder and trunk segments (measured in isolation) influence double poling efficiency, endurance and sprint perf...

INTRODUCTION Although male and female elite skiers possess the same professionalism and general training patterns, it has recently been shown that gender differences increase as the contribution from poling increases. To gain further understanding about this phenomenon, the present study compared sprint and endurance performance, energetic capacit...

Th e present study aimed to examine the eff ects of two diff erent ballistic resistance training regimens, with and without the possibility to utilize the proximal to distal coordination between knee and ankle, upon maximal vertical jump performance. Changes in 1 repetition maximum (1-RM) squat performance, as well as power, force and velocity vari...

INTRODUCTION: Previous studies have shown upper-body strength and power to associate with work economy/efficiency and endurance performance in various types of locomotion. This aspect has not yet been investigated for isolated upper-body work. The present study correlated gross efficiency (GE) and performance with maximal strength and power during...

Physical activity is central in prevention and treatment of metabolic syndrome. High-intensity aerobic exercise can induce larger energy expenditure per unit of time compared with moderate-intensity exercise. Furthermore, it may induce larger energy expenditure at post-exercise recovery. The aim of this study is to compare the excess post-exercise...

INTRODUCTION: Ice sledge hockey is a popular paralympic team sport where players rely entirely on their upper-body to propel themselves rapidly across the ice surface. An ice sledge hockey game is comprised of three periods lasting 15 minutes, and characterized by random variations between short sprints, stopping actions and circular movements. Pre...

Purpose: To investigate performance and the associated physiological and biomechanical responses during upper-body repeated-sprint work. Methods: Twelve male ice sledge hockey players from the Norwegian national team performed eight 30-m sprints with start every 30 s and an active recovery between sprints. Time was captured every 10 m by photoce...

Ice sledge hockey is a popular paralympic team sport where players rely entirely on their upper-body to propel themselves rapidly across the ice surface. The isolated and repetitive poling movements provide a good model for examining upper-body sprint ability and the related movement and strength characteristics. Therefore, the purpose of the prese...

Th e present study aimed to examine the eff ects of two diff erent ballistic resist-ance training regimens, with and without the possibility to utilize the proximal to distal coordination between knee and ankle, upon maximal vertical jump performance. Changes in 1 repetition maximum (1-RM) squat performance, as well as power, force and velocity var...

The purpose of this study was to test whether a long duration of aerobic high-intensity interval training is more effective than shorter intervals at a higher intensity in highly trained endurance athletes. The sample comprised of 12 male and 9 female, national level junior cross-country skiers (age: 17.5±0.4 yr, maximal oxygen uptake (VO2max): 67....

Purpose: The present study describes the distribution of cardiorespiratory fitness (VO2peak) in a large sample of healthy adolescents and the associations between VO2peak, self-reported physical activity, and a selection of conventional markers for future cardiovascular health. Methods: In a substudy of the Young-HUNT study in Norway, 570 adoles...

Purpose: The objective of this study is to examine the effects of acute ingestion of dietary nitrate on endurance running performance in highly trained cross-country skiers. Dietary nitrate has been shown to reduce the oxygen cost of submaximal exercise and improve tolerance of high-intensity exercise, but it is not known if this holds true for hi...

Introduction Sledge ice-hockey is a modified version of regular ice hockey targeting athletes with a physical disability, typically affecting the lower body. An aluminum sledge is used as an adaptive device and each player carries two sticks for puck handling and player movement. Thus, the players rely solely on their upper body to propel themselve...

Introduction Laterality, or limb dominance, is well known feature in both humans and animals. In the cross-country skiing G2 skating technique, skiers use an asymmetrical loaded double pole push synchronous with one leg push (strong side), but without poling on the other leg push (weak side). Anecdotal evidence indicates that most elite skiers mana...

The purpose of the present study was to investigate the relationship between aerobic characteristics and sprint skiing performance, and the effects of high-intensity endurance training on sprint skiing performance and aerobic characteristics. Ten male and 5 female elite junior cross-country skiers performed an 8-week intervention training period. T...

The aim of this thesis was to examine the energy cost of cross-country skiing and to study effects of heavy resistance exercise and intensive endurance training upon physiological characteristics, muscle histology and cross-country ski race performance. Predictions of racing performance included physiological and motivational style variables in eli...

First, to measure the O(2) uptake ([OV0312]O(2)) and the blood lactate concentration during cross-country skiing at competition speed. Second, to compare these entities for the free technique and the classical technique. Further, to establish the subjects' [OV0312]O(2max) and the [OV0312]O(2) corresponding to the onset of blood lactate accumulation...

The performance of the Metamax I and the Metamax II portable analysers for measuring the O2 uptake has been examined during exercise. Healthy subjects ran on the treadmill or bicycled on ergometers while the O2 uptake was measured by the Metamaxes and also by the Douglas bag technique or the Vmax 29 instrument. In the first series of experiments, O...

The purpose of this study was to examine how intense training may affect the maximal O2 uptake and lactate threshold of 11 well-trained male junior cross country skiers (18.7 +/- 0.2 yr) during a 12 wk period which included training on dry land and on snow. The subjects, who had a maximal O2 uptake of 71 +/- 2 ml x kg-1 x min-1 (mean +/- SEM) and a...