Strength Training for Youth Athletes
Introduction
Resistance training (RT) can be defined as a method of conditioning which involves an athlete working against a range of resistive loads to improve athletic performance and overall health (Lloyd et al., 2014). Well informed coaches now recognise the value of resistance training in terms of positive adaptations for youth athletes. The purpose of this piece will be to firstly discuss and refute some of the myths associated with RT for youth athletes. Secondly, the many benefits will be outlined and some practical applications suggested.
Myths and misconceptions
With such a plethora of information available to the public today, it is important to sift through some of the unfounded claims historically associated with RT for youth athletes. National governing bodies such as the UKSCA and NSCA have all released position papers debunking the myths which centre around RT for youths (Behm et al., 2008; Lloyd et al., 2013; Faigenbaum 2009).
The potential impact upon skeletal maturation commonly arises when discussing RT for youth athletes. Reports in the past suggested that RT could cause damage to the epiphyseal plates (growth plates) which exist at the ends of the long bones in children and adolescents. Contrary to these beliefs, childhood and adolescence appears to be the optimal time for bones to respond favourably to weight bearing exercise (Turner & Robling, 2003.)
Coaches should still be wary that younger athletes may to be more likely to sustain physeal stress injuries as repetitive loading of the extremity can disrupt metaphyseal perfusion (Caine et al., 2014). Appropriate loading and correct technique should be cornerstones of any youth athlete RT program. Ossification of epiphyseal plates occurs after puberty due to hormonal changes, so coaches should be mindful of prescribing suitable RT training programs (Zatiorsky & Kraemer, 2006). Previous assumptions that damage may occur at the growth plates, led to the belief that RT could potentially stunt growth in youths. However, these fears were not founded on solid evidence and were perhaps borne out of a small number of papers which highlighted some extremely rare cases of epiphyseal growth plate injuries (Benjamin & Glow, 2003; American Academy of Pediatrics, 2001). The vast majority of reports (Hammill,1994) on RT and youth athletes have not supported these claims, but in contrast have highlighted the value and safe nature of RT for youth athletes when appropriately programmed and supervised. Although peak bone mass may be dictated by genetic factors, participating in regular RT can significantly improve overall bone mass density and total bone mass (Lloyd & Oliver, 2014). Coaches should be aware that the pre-pubertal years see large increases in bone mass due to modelling and re-modelling. RT can provide an osteogenic stimulus for young athletes and has a positive effect on bone health (Lloyd & Oliver, 2012). Consideration should also be given to the positive effect RT can have on preventing osteoporosis in more susceptible groups such as females. Ishikawa et al (2013) highlighted increases of up to 60% in prevalence of osteoporosis within females over 50 during the last 50 years in the United States. With the same authors reporting that 90% of peak bone mass is attained before the age of 20, it seems warranted that young female athletes would include RT early in their careers.
Other concerns surrounding RT for youth athletes focus on the potential injury risk associated with these activities. Many of the injuries reported previously were taken from data gathered from emergency rooms which were aimed at making nationwide projections of the total amounts of injuries related to RT. However, these injuries may have actually been caused by inappropriate loading, poor training techniques, faulty equipment and a lack of qualified adult supervision. (United States Consumer Product Safety Commission. National Electronic Injury Surveillance System. Washington, DC: Directorate for Epidemiology, National Injury Information Clearinghouse, 1979). In reality, all physical activities come with an associated injury risk, but RT is at the low end of the scale in comparison with most sporting activities. Most RT injuries seem to be the result of overly aggressive progression of loading schemes or poor technical competence (Brady et al., 1982).
Assigning a specific age which is appropriate for commencing RT for youth athletes is often debated. Previous concerns about growth plate damage, stunted growth and injury risk have contributed to strength training facilities being restricted to adolescents above the age of 16 (Lloyd et al., 2014). However, Wilson, Bird, O’Connor & Jones (2017) outline that young athletes can participate in strength training from as young as 5-6 years old once they are capable of following instructions, have an understanding of safety procedures and are competent in basic postural control and balance. Reframing the idea of strength is important here as for these younger age groups RT could mean mastering bodyweight exercises before any additional external loading takes place.
The many benefits
Alongside benefitting bone health, there are many positive implications for young athletes who engage in appropriate RT programs. RT can provide significant benefits for those seeking body composition changes. Childhood obesity is on the increase in many parts of the world and societal changes have led to decreased levels of physical activity. Participation in RT programs may be an easier way for overweight children to exercise in comparison to longer sessions which include larger volumes of aerobic exercise such as running. Completing a structured RT program can increase muscular strength, improve lean mass and reduce body fat. (Lloyd et al., 2014; Faigenbaum et al; 2013)
For youth athletes, improving muscular strength is a much sought after training goal. Increasing muscle CSA has been noted as a key factor in increasing force production (Jones et al., 2008). Lloyd et al (2014) state that development of muscle CSA will typically result in adolescents increasing their ability to express force. Coaches should be aware of the role that growth and maturation play in development of muscular strength and that the normal patterns of maturation will see increases in muscle CSA regardless of taking part in RT (Peitz et al, 2018). However, it appears plausible to state that participation in RT will lead to enhanced gains in strength, outside of the processes of maturation, through increases in CSA and pCSA based on athletes adhering to a well-planned and appropriate training program. The optimal time period for this growth would appear to coincide with the increase in circulating androgens, namely testosterone, which occurs after the onset of puberty.
Coaches should be mindful of the differences in strength gains that may be seen around this stage in boys and girls with muscular size development more apparent in boys as a result of increased hormonal concentrations (Lloyd et at., 2013). From a practical standpoint, coach education should include understanding of how to monitor peak height velocity using protocols like the Khamis-Roche method within young athletes (Khamis-Roche,1994). Knowledge of peak height velocity can aid a coach in understanding when the young athlete is experiencing their maximal growth spurt and when certain training programs may be most suitable. In the case of hypertrophy focused training, the biggest gains may be seen after the onset of puberty in response to higher levels of hormone availability.
Strength gains seen in pre-pubertal children who participate in RT programs are suggested to occur due to neurological factors (Bernhardt et al., 2001). A lack of circulating androgens limits cross sectional area increases, with improvements in motor unit recruitment patterns and coordination levels likely to explain strength gains in this group (Sale et al.,1983). Studies such as those completed by Lambertz et al (2003) have highlighted children’s improved ability, within a specific task, to activate agonist muscles after RT participation with subsequent decreases shown in antagonistic co-activation. These improved recruitment and activation patterns can lead to more efficient sporting movements in young athletes.
Improvements garnered at muscular, tendinous, skeletal and neural levels can help to enhance specific qualities for all young athletes. In addition to muscular increases leading to strength development, additional benefits include potential increases in speed, power and increased robustness to minimise injury risk. Speed and acceleration are directly related to the amount of force an athlete can express, so development of high levels of force would appear relevant to enhancing speed (Lloyd et al., 2011). Appropriate RT can assist in combatting potential increases in body mass during puberty by allowing the athlete to apply more force relative to their body weight (Lloyd et al., 2011).
Improvements in rate of force development can be seen if appropriate RT programs are implemented. Improved RFD is highlighted by high levels of force expressed in shorter time periods, a quality that is most desirable in sporting settings. Dotan et al (2012) highlighted the lower RFD seen within children in comparison to adults suggesting it is a result of an inability to recruit fast twitch fibres efficiently. Targeted training with a focus on intent to move load quickly can enhance RFD for young athletes. Moving loads with maximal intent should occur only when technical proficiency has been mastered.
Creating robust athletes who can tolerate the stresses of training and competition is always a target for coaches. Lloyd et al (2016) suggest that implementing RT programs with youth athletes can help to strengthen the muscles and connective tissues that must withstand high external forces during sport. As a result there is a decrease in the likelihood of soft tissue injury.
RT may also have a positive impact on the psychosocial health of youth athletes. Tucker (1987) showed that females who completed a 12 week RT program had improved self- efficacy and self-esteem scores. If appropriate RT programs are implemented and young people are encouraged to feel positive their training, then RT programs could potentially have similar impacts to being involved in team sports (Faigenbaum et al., 2009). With increased levels of mental health issues within youth populations this may be added benefit for involvement in RT programs to improve self-esteem, body confidence and overall well-being.
Practical Implications
Renowned youth athlete expert Avery Faigenbaum et al (2009) provides some simple guidelines for youth strength training that should be adhered to. Qualified coaches should be in place and sessions should take place in a safe environment. Adequate warm ups should be included in each session. Volume should be controlled with 1-3 sets of 6-15 repetitions recommended for beginners. Light to moderate loads may be used with bodyweight exercises being an excellent starting point. Technique should always be prioritised firstly before adding load. Faigenbaum suggests that coaches should adjust the training program based on the needs, goals and abilities of the individual. Awareness of the athlete’s training age and stage of maturation should also be considered.
References
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