The present study aimed to retrospectively compare MIPs extracted from training and competitive sessions throughout an 8-week in-season cycle in an elite male FH team. The analysis of more than 300 individual recordings revealed that peak intensities during training neither reached competition intensities for distance- nor acceleration-based metrics. A comparison of effect sizes between the different inspected outcomes (TD, HIR, SPRINT, and ACCEL) indicated higher discrepancies between training and competition for distance-based metrics. No systematic differences were observed concerning the length of the window chosen for MIP extraction. The observed discrepancies between training and competition intensities provide important implications for the design of training sessions in FH and team sports.
As a key finding of this study, the analysis revealed that distance-based MIPs during training significantly failed to reach the magnitude of peak intensities observed during competitive matches. As shown in Figs. 1 and 2, TD-, HIR- and SPRINT-based MIPs did not reach the intensities the players experienced during competitive matches on the weekend. In comparison to a previous study extracting MIPs from matches in high-level female FH players by McGuinness et al. (2022) and Delves (2019), the MIPs extracted in the present study were slightly lower, particularly for high-intensity MIPs (HIR and SPRINT). However, the MIPs experienced during the competition were still ~ 40 to 60% higher than the peak intensities observed during the training sessions. Therefore, it might be stated that the intensity of training sessions was not high enough to prepare the players for competition intensities.
Discrepancies in intensities between training and competitive session intensity have been observed and reported in previous analyses of team sports. For instance, Oliva-Lozano et al. (2022) analyzed activity data from professional soccer players over a consecutive in-season period and reported that match days induced a higher load on the players compared to training sessions. Similar observations have been made in professional handball players (Font et al., 2022) and youth soccer players (Szigeti et al., 2021) through retrospective analyses. On the one hand, a tapering of training load between matches seems reasonable to reduce the metabolic and mechanical load and boost the performance capacities of a player (Vachon et al., 2021). However, exercise sessions that are not representative of competitive characteristics are likely to fail to induce the physiological overload needed for physiological adaptations relevant to performance (Delaney et al., 2017). The present study identified a discrepancy between training and matches also for the maximum intensities experienced during exercise. One issue of not preparing players for competitive MIPs during training is that the latter is associated with fatigue-initiated reductions in physical performance. Schimpchen et al. (2021) observed reduced high-intensity running activity for five consecutive minutes after individual MIPs. Therefore, MIPs seem to display severe physiological stressors athletes are not familiarized with during regular exercise sessions.
A possible reason for this discrepancy between peak intensities could be found in training routines in team sports, such as the focus on technical-tactical content during the season and the utilization of SSGs to simulate game situations (Weaving et al., 2022). For instance, Duthie et al. (2019) already reported in a sample of FH players that typical training contents, e.g. SSGs, do not reach the distance-related intensity of competitive matches, but do so for acceleration-based metrics. Lacome et al. (2018) also described this phenomenon concerning MIPs in soccer players comparing SSGs and competitive matches (Lacome et al., 2018). Among other reasons, the reduction of court dimensions and potential running distances was discussed as a possible reason for lower distance-based intensities. Findings from Martin-Garcia (2019) on soccer players support the observation that particularly for high-speed activities, SSGs seem insufficient to stimulate competition-like intensities. Further, the ecological context of training drills seems to affect the peak intensities a player can experience. For instance, Sansone et al. (2023) reported that the focus on skill-related exercises exposes players to lower intensities than game-based exercises (Sansone et al., 2022). Therefore, the present study supports previous studies claiming insufficient intensities in (FH?) team sports training, with a specific focus on MIPs as short, but strenuous periods of activity. A possible solution could be increasing the court dimensions in the SSG to maintain the spatial characteristics of the team sports and avoid reductions in speed and running demands (Lacome et al., 2018).
In addition to distance-based metrics, acceleration-based MIPs revealed discrepancies between training and competition intensities. Particularly for MIPs calculated across time windows ≥ 2 minutes, significantly higher MIPs were observed for competitive sessions. Based on effect size estimation and the observation of MIP distribution in Fig. 1, it can be stated that training-competition discrepancies for acceleration-based MIPs are less drastic than for distance-based metrics (TD, HIR, and SPRINT). Furthermore, the effect sizes indicate higher differences between competition and training for a larger MIP window length. Considering that several studies suggested that SSGs better match acceleration- than distance-based competition intensities and partly extend the latter (Duthie et al., 2019; Lacome et al., 2018; Oliva-Lozano et al., 2022), the reduction of court dimensions seems to be effective in preserving game-like acceleration demands. However, the significant differences in acceleration data observed in the present study are likely to result from the pooling of all recorded exercise sessions within the analyzed period of the season. Considering the variability of training intensities in terms of micro-cycle periodization, it seems legit that not all exercise sessions reach competition intensity (Oliva-Lozano et al., 2020, 2022). Furthermore, the duration of SSGs is frequently restricted to bouts of a few minutes with intermittent breaks (Duthie et al., 2019), so an increased intensity over several minutes cannot be reached in such types of game-based exercise.
As a final observation of this study, it is worth noting that the discrepancy between training and competition was in parts moderated by the window length chosen for MIP extraction. Several studies indicated that the length of the analyzed window modulates the severity of differences between the average and peak intensity and highlighted the importance of the choice of window length for the description of peak intensities (Delves et al., 2019; McGuinness et al., 2020). For comparison of training and competition data, the length of the chosen window had a substantial impact on ACCEL-based MIPs (Table 1) and amplified the discrepancy between training and competition. Further, the different metabolic demands associated with high-intensity exercise such as SSGs of varying window length (e.g. 1 minute vs. 5 minutes) should be considered when using objective MIP values as benchmarks for training design (Gaudino et al., 2014). To prepare an athlete for the intermittent and variable demands of the competition, it could be important to implement SSG formats of varying lengths for simulating worst-case scenarios experienced during competition across different time scales.
Limitations
Despite the important implications of this study for exercise planning, several potential limitations must be considered. First, only one team was analyzed, so team-specific routines may have contributed to the discrepancy between training and competition MIPs. Although such discrepancies have been reported previously (Lacome et al., 2018), it is highly recommended to compare MIPs from training and competition for each team specifically before re-calibrating training intensities. Further, the present approach is restricted to the physical demands of team sports. While training routines such as SSGs seem to not match the physical requirement of the competition yet, an intensification of non-physical aspects such as tactics and techniques compared to the match demands might be still given (Clemente et al., 2021). Therefore, coaches and scientists are requested to treat the observation of the present study as a piece of complementary information for the optimization of training.