Background: Individually adjusting the training load of athletes is of undeniable importance, in optimizing adaptation and performance gains, however, this individualized approach has
been a challenge for coaches especially in team sports. The countermovement jump (CMJ) height with the minimal individual difference (MID), an individual’s typical error of measurement and the
respective confidence interval, has been suggested as a method for monitoring and regulating training load. Therefore, the purpose of this study is to introduce a method that can be applied by
researchers and practitioners to individually adjust the training load of team sports athletes.
Methods: Initially, the participants were familiarized with the CMJ. Thereafter, two reliability sessions were conducted after a 24h interval from the last familiarization session.
Thereafter, it was possible to calculate the MID of each participant as detailed in Equation 1: MID=(SDdiff÷√2)×2.145(1) where, MID is minimal individual difference, SDdiff is standard deviation of
the difference score i.e. the difference between the scores of jumps performed in session 1 and session 2 of the reliability testing, and 2.145 is used to establish the 95% Confidence Intervals (CI)
according to the distribution of probability for t(14) as p<0.05. In the T0 CMJ height was assessed with a contact mat to determine jump height. The mean of 8 jumps was used for analysis. The
participants were randomly allocated into: the regulated group (RG; n=9) and the control group (CG; n=9). The CG performed 4 weeks of periodized training, the aim of weeks 2 to 3 were to elicit
decreased or stable CMJ height, whereas the aim of week 4 was to decrease jump height (induced overreaching). For the taper weeks, increased CMJ height was the goal. With regards to the RG, CMJ height
and associated MID were assessed at the beginning of each week, and if necessary, training loads were modified. At the end of these 4 weeks of intensified training loading (T1) and after 2 weeks of
tapering (T2), the participants were reassessed. To quantify the training load, the session-rating of perceived exertion was used. The differences between groups and across time points were analysed
via a 2 way ANOVA.
Results: In the RG, the MID loading was increased in weeks 3 and 4 (8.2% and 14.5%, respectively; p<0.001) compared to the pre-planned loading of the CG during the overreaching phase.
However, the final training load did not differ significantly between groups (p=0.082). In terms of the jump results, the RG significantly (p<0.05) reduced CMJ height during T1 (ES=-0.31: 95%CI:
-0.58,-0.02), however there were no significant changes in the CG jump height. At T2, the RG significantly increased CMJ height above baseline (ES=0.30:95% CI:0.09,0.51).
Conclusion: Researchers and practitioners could use the CMJ with MID to regulate and monitor training load in team sports athletes. In terms of utility, the CMJ assessment requires
little equipment, it is easy to manage and can be easily applied in the field.