David Sundström

Mid Sweden University · Sports Tech Research Centre, Department of Quality Technology and Management, Mechanical Engineering and Mathematics

Purpose The aim of this study was to develop and validate a bioenergetic model describing the dynamic behavior of the alactic, lactic, and aerobic metabolic energy supply systems as well as different sources of the total metabolic energy demand. Methods The bioenergetic supply model consisted of terms for the alactic, lactic, and aerobic system me...

Purpose: To develop a method for individual parameter estimation of four hydraulic-analogy bioenergetic models and to assess the validity and reliability of these models’ prediction of aerobic and anaerobic metabolic utilization during sprint roller-skiing. Methods: Eleven elite cross-country skiers performed two treadmill roller-skiing time trials...

The aim of the study was to investigate the influence of slope and speed on lower-limb kinematics and energy cost of running. Six well-trained runners (VO2max 72 ± 6 mL·kg-1·min-1) were recruited for the study and performed: 1) VO2max and energy-cost tests and 2) an experimental running protocol at two speeds, 12 km·h-1 and a speed corresponding to...

Introduction Downhill running poses challenges were the gradient is of importance for energy cost and oxygen uptake. While demonstrated that downhill running at a slight gradient is most efficient, the energy cost increases with a steeper gradient (1). However, the additional effect of running speed has not been studied for downhill running. Theref...

The purpose of this study was to evaluate and compare various power output estimates and estimate anaerobic energy supply during treadmill roller-skiing. Roller-skiing sprint time-trial performance on a treadmill was compared to numerical simulations of three different power output estimates; non-inertial power estimate (NIP), inertial power estima...

It has been shown theoretically that performance can be enhanced by varying power in parallel with variable ambient conditions. However, no theoretical model has considered aerobic substrate utilization dynamics, limited carbohydrate stores, force–velocity relationships, and proper efficiency modelling. Furthermore, no study has investigated optima...

It is desirable to test sportswear and sports equipment at exactly the same conditions experienced during use. Although outdoor tests are in many cases the most adequate, they are at the same time quite complex, demand special measurement technology and wearable equipment. Results of such tests are often hard to interpret due to large variations be...

Bioenergetic models for exercise performance simulations and pacing strategy optimizations currently lag behind empirical knowledge in human bioenergetics. Therefore, the objective of this study was the construction of a four-compartment hydraulic bioenergetic model that incorporates separate oxidative phosphorylation of lipids and carbohydrates an...

Cross-country skiing, biathlon and ski orienteering are competitive sports with practitioners who are mostly from countries in the northern hemisphere. The competition season is during the time when the ground is covered with snow, which roughly extends from mid-November to late March. During the rest time of the year, which is a long preparatory p...

Performance in endurance sports depends on the athlete's ability to generate power output through muscle contraction. The energy requirements of muscles are satisfied by the alactic and lactic bioenergetic pathways, working anaerobically, and the aerobic oxidative phosphorylation of fats and carbohydrates. The aim of this study was to apply further...

Abstract Road cycling races in general, but particularly criteriums (short circuit race), have a considerable number of bends along the race course. Sharp bends force the rider to decelerate in order to retain the grip between the tires and the road. This study focused on how these course bends influence the optimal pacing strategy in road cycling....

Road cycling performance is dependent on race tactics and pacing strategy. To optimise the pacing strategy for any race performed with no drafting, a numerical model was introduced, one that solves equations of motion while minimising the finishing time by varying the power output along the course. The power output was constrained by two different...

Abstract The wide-spread use of power-meters in today's competitive road cycling has been an incentive for optimizing the distribution of power output i.e. the pacing strategy. Therefore, the aim of this study was to examine the effects of course profile on the optimal pacing strategy in road cycling. For that reason, three course profiles, built u...

When studying events involving locomotive exercise, such as cross-country skiing, one generally assumes that pacing strategies (i.e. power distributions) have a significant impact on performance. In order to better understand the importance of pacing strategies, a program is developed for numerical simulation and optimization of the pacing strategy...

During events involving locomotive exercise, such as cross-country skiing, it is believed that pacing strategies (i.e. power distribution) have a significant impact on performance. Therefore, a program was developed for the numerical simulation and optimization of cross-country ski racing, one that numerically computes the optimal pacing strategy f...