As part of American Heart Month in February, I penned a few posts on aerobic fitness in youth and adults.
In the past month, I have been reading and writing frantically to complete an overdue book chapter for the 2nd edition of Endurance Training - Science and Practice. The chapter provides an overview of the research on endurance capacity and trainability of youth.
In the first edition (2012), we focused primarily on the traditional endurance athlete - runners, cyclists, and swimmers (and triathletes) of long, sustained distances with some mention of the health benefits of aerobic activity and a high V̇O2max for general health of all youth.
The second edition could have been much simpler than I made it. We (co-authors: Jason Hettler, former PhD student Clemens Drenowatz, and my PhD mentor Bob Malina) could have simply searched the related literature from the time of the first edition to now and updated the references and any new findings. But instead, we decided to think more broadly about endurance in young people and young athletes and expand it to sports that require a significant aerobic component (mixed energy system/intermittent, repeat high-intensity bouts; soccer, basketball, etc.) and again also highlight the importance of the health aspect of aerobic activity for all youth given the continued ills associated with our contemporary society of sedentary behaviours.
A Games-based Approach to Aerobic Fitness
What? Games. Aerobic Fitness. In the same sentence?
Yes, indeed. One aspect that I really wanted to emphasize was the games-based approach to practice and training to develop aerobic capacity, whilst also enhancing the technical/tactical and skill development of court/field and team sport athletes. It’s also important to note that this can also have implications for non-athletes as well. Why? Because kids love games!! Heck, teens love games. And so do adults … and this all might be part of the reason that compliance with conventional sustained aerobic activity is relatively poor - it’s boring for most people!
[Special shout-out to Jason Hettler and Johnny Parkes for inspiring this topic. I met these colleagues at IMG Academy, and both had a great grasp of LTAD principles and especially the “conditioning” component.]
Key Papers
A few papers are worth mentioning here related to the games-based approach for team sport athletes (and of course all youth).
📰 Moran et al. Effects of small-sided games vs. conventional endurance training on endurance performance in male youth soccer players: a meta-analytical comparison. Sports Medicine, 49(5), 731–742, 2019.
In this meta-analysis of 7 studies comparing small-sided games (SSG) to conventional endurance training among male adolescent soccer players, SSG were found to be as effective as conventional endurance training for increasing aerobic endurance performance. The analysis also revealed that the training effect requires two sessions per week with ≥ 4 sets of 4 minutes of activity interspersed with recovery periods of 3 minutes for ≥ 8 weeks.
📰 Landgraff et al. Longitudinal changes in maximal oxygen uptake in adolescent girls and boys with different training backgrounds. Scandinavian Journal of Medicine & Science in Sports, 31(S1), 65–72, 2021.
For team or skill sport athletes, the emphasis of designing effective and efficient training sessions that enhance both endurance and the acquisition of motor skills is important. This is supported by this paper comparing boys and girls engaged in organized training with either a high volume of endurance training (~7 hours per week) or a primary focus on technical and tactical skill development with a low volume of endurance training (~1.6 hours per week). Although the initial V̇O2max values were higher in the endurance trained groups, there was no difference between the training groups in the development of V̇O2max between the ages of 12 to 15 years. Thus, the authors concluded that high volumes of systematic endurance training do not have an additional effect on V̇O2max compared with a similar volume of training mainly aiming at developing motor skills.
📰 Harrison et al Development of aerobic fitness in young team sport athletes. Sports Medicine, 45(7), 969–983, 2015
Although the findings and conclusions of review papers and meta-analyses provide some general recommendations for aerobic training in youth, few guidelines align with LTAD principles and stages of development. To determine current best practices for aerobic fitness development aligned with growth and development and LTAD stages, Harrison and colleagues reviewed and analysed aerobic training studies in young athletes. Based on theory and research, the authors recommended the following:
Pre-pubertal years (about ages 6-12 years of age)/Foundation Phase: a young athlete should be sampling multiple sports in which aerobic fitness training is integrated into sport-specific drills, activities and skill-based games.
Mid-adolescence (about ages 13-15 years of age)/ Developmental Phase: a young athlete may show an increased commitment or specialization to a chosen sport, where training to develop aerobic fitness should prioritize high-intensity SSG to simultaneously develop aerobic fitness and technical skills.
Late adolescence (16-18 years of age)/Performance Phase: Once athletes enter the investment stage or the pursuit of proficiency in a chosen sport, a combination of SSG and HIIT is recommended.
Final Thoughts
These research findings and recommendations are important for a few reasons:
1) SSG and invasion games can allow both endurance and sport skills training to be carried out simultaneously, thus providing a more efficient training stimulus, and
2) practical experience informs us that young people and youth athletes enjoy games more than conventional endurance training methods, whether that be long slow distance or intervals.
So, instead of a 2-mile run for the middle school football team - which is dumb anyways - let them play sharks and minnows. Or maybe team handball or ultimate frisbee for your AAU basketball team (unless of course they are playing a 6 game weekend tournament - and yes that is sarcasm). Either one of those games, along with many others, would be a great for any summer camp kid, and also a fun and engaging way to start any practice as a general warm-up. I imagine there are some social-emotional learning aspects for Phys Ed in there as well.
Bottom line: Conditioning and getting kids “in shape” does not need to be boring, long steady state runs, especially at the younger ages. This also does not mean that this approach is “for kids” and not for your high school kids. In contrast, you will conditioning them without them even knowing it. And last, I am not saying that long slow distance, tempo runs, or intervals do not have a place in conditioning adolescent athletes …. I’m just saying that you have tools to consider in your exercise prescription / program design. As always, it’s an art based on science.