Background: The usage of the Force-Velocity relationship for individualizing training regimes for athletes has increased in popularity. This can be done through measurements of muscle mechanical properties and creating individual force-velocity profiles. To do this, one must use valid and reliable test equipment. These types of equipment are often expensive and impractical, which limits the usage to a small population with the right financial means. Therefore, the purpose of this study was to examine the concurrent validity of the inertial sensor Vmaxpro for measuring muscle mechanical properties. Method: 52 male ice-hockey players (age:17.9 ± 2.2 years, body weight: 77.7 ± 10.6 kg, height: 180.3 ± 6.2 cm) participated in this study and performed two jumps each on four different loading conditions (unloaded, 25, 50 and 75% of BW). The jumps were recorded simultaneously with an inertial sensor and a linear transducer. Three different variables were analyzed: peak velocity (pV), average velocity (avgV) and average power (avgP). Pearson’s correlation coefficient (r), linear regression analysis, Bland-Altman analysis, and standard error of estimate (SEE) was used to examine the concurrent validity. Results: The results showed a strong correlation, agreement and small SEE for pV: r=0.98, bias = -0.12, SEE = 0.08, for avgV: r=0.98 bias = 0.01, SEE = 0.04 and for avgP: r = 0.97, bias = 30.94, SEE = 73.47. Practical application: The results from the present study indicate that the Vmaxpro can be used for assessing muscle mechanical properties. Furthermore, since the Vmaxpro is both cheap and portable, it can potentially expand the usage of test equipment to clubs and associations with limited budgets.

The purposes of this dissertation were to examine the agreement the agreement between double integration using the trapezoidal method and measurements for push-off distance to create force-velocity profiles, examine the change in push-off distance between loading conditions when force-velocity profiling, and to observe the alterations in mechanical outputs of force-velocity profiles after 15-weeks of off-season training. The major findings are as followed. Using double integration with the trapezoidal method may be a reliable way to estimate push-off distance, despite a small systematic bias. This bias should have negligible effects on push-off distance and therefore not alter or effect calculations in a meaningful way. Therefore, using double integration for push-off distance estimation may provide the ability to retrospectively create force-velocity profiles. The analysis of change in push-off distance at each loading condition suggests that there is 5-10% change in push-off distance between conditions. The significant changes in push-off distance occurred between the bodyweight condition and 20 kg as well as bodyweight and 40 kg loading conditions. The observed mechanical output alterations after training did not yield any significant changes in mechanical outputs. However, based on the observed output changes in conjunction with the previous training, force-velocity profiling may be primarily indicative of acute training styles.