In cycling, performance models are used to investigate factors that determine performance and to optimise competition results. We present an innovative and easily applicable mathematical model describing time-resolved approaches for both the physical aspects of tractional resistance and the physiological side of propelling force generated by muscular activity and test its validity to reproduce and forecast time trials in track cycling. Six elite track cyclists completed a special preparation and two sprint time trials in an official velodrome under continuous measurement of crank force and cadence. Fatigue-free force-velocity profiles were calculated, and their fatigue-induced changes were determined by non-linear regression analysis using a monoexponential equation at a constant slope. Model parameters were calibrated based on pre-exercise performance testing and the first of the two time-trials and then used to predict the performance of the second sprint. Measured values for power output and cycling velocity were compared to the modelled data. The modelled results were highly correlated to the measured values (R2>0.99) without any difference between runs (p>0.05; d<0.1). Our mathematical model can accurately describe sprint track cycling time trial performance. It is simple enough to be used in practice yet sufficiently accurate to predict highly dynamic maximal sprint performances. It can be employed for the evaluation of completed runs, to forecast expected results with different setups, and to study various contributing factors and quantify their effect on sprint cycling performance.

In track cycling sprint events, optimal cadence PRopt is a dynamic aspect of fatigue. It is currently unclear what cadence is optimal for an athlete’s performance in sprint races and how it can be calculated. We examined fatigue-induced changes in optimal cadence during a maximal sprint using a mathematical approach. Nine elite track cyclists completed a 6-s high-frequency pedaling test and a 60-s isokinetic all-out sprint on a bicycle ergometer with continuous monitoring of crank force and cadence. Fatigue-free force-velocity (F/v) and power-velocity (P/v) profiles were derived from both tests. The development of fatigue during the 60-s sprint was assessed by fixing the slope of the fatigue-free F/v profile. Fatigue-induced alterations in PRopt were determined by non-linear regression analysis using a mono-exponential equation at constant slope. The study revealed that PRopt at any instant during a 60-s maximal sprint can be estimated accurately using a mono-exponential equation. In an isokinetic mode, a mean PRopt can be identified that enables the athlete to generate the highest mean power output over the course of the effort. Adding the time domain to the fatigue-free F/v and P/v profiles allows time-dependent cycling power to be modelled independent of cadence.

Background: Evaluation of power-force-velocity profiles in ballistic push-offs and in sprint movements are beneficial to enhance sport performance. There have only been a few studies investigating force-velocity profiles in rotational movements and there have not been any studies conducted on golf specific rotational movements. There is a lack of isoinertial power assessment protocols which can relate to golf swing performance. For this reason, 1080 Quantum was used for testing which is a machine able to measure power, force and velocity in several different resistance modes. Aim: The aim was to study the reliability of three golf specific rotational tests and to assess the reliable test’s validity. The secondary aim was to study the isoinertial force-velocity and power relationship in tests that assessed acceptable test-retest reliability and acceptable construct validity. Methods: Twelve high level golfers (handicap -1.5±1.2), 8 men and 4 women performed the tests with five different loads; 2 kg, 6 kg, 10 kg, 14 kg and 18kg with three golf specific rotational movements in a motorized cable machine (1080 Quantum, Sweden). The three new tests utilized were: full body rotational test (FBRT), thorax rotational test (TRT) and pelvis rotational test (PRT). Data gathered was used to study golfer’s individual force-velocity profile and to assess construct validity of the reliable tests against previously recorded normal-swing driver clubhead speed (CHSnormal), and maximum-swing driver clubhead speed (CHSmax). Construct validity was based on á priori stated hypothesizes, and data were analyzed with Spearman’s correlation coefficient (rs). Intraclass correlation coefficient (ICC) and coefficient of variation (CV) was used to assess test-retest reliability of FBRT, TRT and PRT. Results: In the reliability assessment, the highest peak power (PP) (ICC, 0.968, 95% CI (0.889- 0.991)), corresponding peak force (PF) (ICC, 0.993, 95% CI (0.96- 0.998)) and corresponding peak velocity (PV) (ICC 0.773, 95% CI (0.17- 0.936)) was only found to be acceptable in FBRT. Construct validity assessment of FBRT was not found acceptable in either of the resistances. The calculated average slopes indicated a velocity dominant force-velocity profile for women and a force dominant for men. Conclusion: The study demonstrated that only the FBRT assessed acceptable test-retest reliability for measuring force, velocity and power. Based on our hypothesizes FBRT is not a valid indicator of golf performance on either resistance, however it had a significant moderate to good correlation with CHSmax and with CHSnormal at all resistances apart from 2 kg. FBRT should not be applied as a test, nor to be used for the calculation of the force- velocity profile since it is not valid, even though it is reliable. since it is not valid, even though it is reliable. As a result, FBRT could only be used for exercise and needs further development to improve its validity. / <p>While only my name is featured on the title page of this thesis, it reached its final stage with the guidance and support of many others. I thank my primary supervisor, Ann Bremander and James Parker whom, with their professional guidance, helped complete this thesis.</p>