Monitoring training load in youth soccer players: effects of a six-week preparatory training program and the associations between external and internal loads

Abstract

This study examined the effects of a six-week preparatory training program on physical performance and physiological adaptations in junior soccer players. Additionally, we investigated whether a relationship existed between external and internal loads. Youth soccer players (aged 16 years old) from a youth football academy participated in six weeks of pre-conditioning training. Wireless Polar Team Pro and Polar heart rate sensors (H10) were used to monitor physical performance indicators (sprint and acceleration scores, covered distance, maximum and average speed and duration), physiological responses (maximum and average heart rate [HR] and R-R interval, time in HR zones 4+5, and heart rate variability [HRV]), and training load score. Additionally, muscle status and rating of perceived exertion (RPE) scores were measured using digital questionnaires. Significant increases were observed in the majority of physical performance indicators [i.e., sprints (p = 0.015, ES = 1.02), acceleration (p = 0.014, ES = 1), total distance (p = 0.02, ES = 0.87), as well as maximum speed (p = 0.02, ES = 0.87)]. A trend towards improvement was observed in the remaining performance indicators (i.e., distance/min and avg speed; ES = 0.6), training load (ES = 0.2), muscle status (ES = 0.3)), and all physiological responses parameters (ES = 0.1 to 0.6). Significant correlations were found between the majority of external load parameters (i.e., performance indicators) and objective (i.e., physiological responses) and subjective (i.e., RPE, muscle status) internal load parameters (p < 0.001). The highest number of moderate-large correlations were registered between performance indicators and time in HR zone 4+5 (0.58 < r < 0.82), training load (0.53 < r < 0.83), average HR (0.50 < r < 0.87), maximal HR (0.51 < r < 0.54) and average R-R interval (0.58 < r < 0.76). HR zone 4+5, average and maximal HR, average R-R interval, and training load score may help control training parameters and reduce the risk of under- or over-training in youth soccer players. However, these conclusions should be confirmed and replicated in future studies with more diverse subject populations.

A new database of the analysis of the physiological needs in amateur female basketball during official matches

“…Various indicators have been employed to assess internal load (IL) in basketball. These indicators encompass the analysis of HR dynamics 7 , 8 , Rating Perceived Exertion (RPE) 9 , 10 , as well as their interrelationship 11 . Furthermore, the hormonal profile, specifically the testosterone-cortisol ratio 12 , 13 , and the concentration of metabolites such as lactate or ammonium 14 , 15 , have also been examined.…”

Follow-Up Weekly Training Distribution and Accumulated Internal Load Effects on Young Football Players’ Well-Being, Physical Fitness, and Technical Performance

“…Soccer (or football) is characterized by intermittent efforts at different intensities and durations in which its performance is determined by the integration and interaction of physiological and biomechanical aspects, tactical-technical ability, external-internal training load optimization, and mental skills, among others [ 1 , 2 , 3 ]. However, in light of recent trends in young soccer performance, there is growing concern about detailed information on the relationship of comprehensive factors to young soccer performance [ 2 , 4 , 5 ]. Thus, a deeper understanding is possible when exploring training program issues and integrated longitudinal data assessment in parallel [ 2 , 3 ].…”

“…Additionally, small-sided and conditioned games (SSG) should be included, as well as skill-based training (SBT), to encourage physical, physiological, and technical improvements [ 6 , 10 ]. This study of short-term pre-season training, which includes physical fitness, psychological factors, technical skills, and team tactics, significantly influences the development of jumping and running ability, speed and strength-based conditioning, motor skills, and aerobic endurance in young soccer players [ 5 , 10 ].…”

“…Despite this interest in pre-season training, different approaches have been identified to address the challenges coaches face in managing the amount of internal and external training load and their well-being status (such as stress, fatigue, muscle soreness, and sleep quality) during the pre-season period. These approaches aim to monitor the improvement of physical and physiological performance [ 1 , 2 , 6 ], account for variations in training responses [ 11 ], and prevent neuromuscular fatigue and soreness, which can increase the risk of injuries and negatively impact skill and balance in soccer players at all levels, from young national players to elite international players [ 5 , 12 ]. From these perspectives, subjective and objective measurement and monitoring of the complex process of the individual stress response to training, particularly in young Soccer players, is necessary to maintain the unique balance required for homeostasis [ 13 ].…”

The Quantification of Physical Performance and Internal Training Load in Youth Male Soccer Players During Preseason

“…For example, the quantification of internal training load is commonly assessed among youth soccer players using session ratings of perceived exertion (sRPE), with wellbeing questionnaires used to assess the response to training loads 13,14 . Significant correlations between physical performance (i.e., sprint, total distance, maximum speed, average speed) and ratings of perceived exertion (RPE) in training sessions have been found in adolescent soccer players examined during six weeks of preseason 15 . However, how these relationships change when match-play is considered and how external load is linked with internal load and changing perceptions of wellbeing (measured via questionnaires) remains unknown in youth soccer players 16 .…”