Some common questions I hear from parents regarding strength training programs are, is it safe, is it effective and how hard should intensity be (load)? Data collected in the 1970s and 1980s concluded that resistance training was unsafe for children and adolescents and this dogma has prevailed. However, further analysis of the data showed that the injuries were caused by inappropriate training techniques, excessive loading, poor equipment and a lack of qualified supervision (Faigenbuam, 2009). In short, a well-designed, age appropriate strength program which takes into account maturational age and experience, is well supervised and progressed appropriately will put the child at a lower risk of injury and will improve their performance in sport. If you’re interested in learning more, read on………..
The primary concern surrounding strength training young athletes has been potential damage that may occur to growth plates. These can be separated into 3 main sites: the epiphyseal plate (a cartilage plate in the metaphysis at the end of long bones), the cartilage lining the bone of the joint (articular cartilage) and at the junctures where the bone meets the tendon, known as the apohpysis (Faigenbaum, 2000). The concern is that damage can occur which would cause the growth plate to fuse earlier than normal, resulting in a premature cessation of growth. A secondary concern would be that strength training is ineffective in preadolescent athletes due to a low level of androgens which promote muscle hypertrophy.
Interestingly, Faigenbaum and Myer (2010) found very little data which supported the notion that strength training increases injury risk in children or adolescents who follow age related guidelines and are well supervised. In fact, the National Strength and Conditioning Association recommend strength training as an effective method by which to reduce the incidence of sport-related injuries. Faigenbaum (2009) found that of 1576 sports related injuries reported in a study of school-aged youth, resistance training comprised 0.7% of injuries while football represented 19%. Conclusion? The incidence of injury in young athletes is WAY higher in their sports than in strength training. Vaughn and Micheli (2008) report that the few instances in which strength training resulted specifically in epiphyseal plate damage were the result of poor lifting technique, lifting maximal loads and having inadequate supervision. In addition, it has been suggested (Faigenbaum, 2000) that the preadolescent child is actually less vulnerable to growth plate damage when compared to the period around puberty and PHV as the growth plates in preadolescents seem to be stronger and more resilient to shearing forces. Faigenbaum and Myer (2010) comment that “in the vast majority of resistance training intervention studies summarized….the injury occurrence in children and adolescents was either very low or nil and the resistance training stimulus was tolerated well by subjects” (p.57).
During puberty, a ten-fold increase in testosterone is found in boys that can have a profound influence on the development of muscle mass (Faigenbuam, 2010). Girls benefit less from an increase in testosterone, but will experience an increase in the production of estrogen around puberty which will result in a widening of the hips, increased body fat and breast growth. Muscle mass increases more markedly in boys than it does in girls due to the greater presence of testosterone (an anabolic hormone). It is a common strategy to enhance muscle growth following PHV using strength training to promote hypertrophy. The peak incidence of damage to the ephiphyseal plate occurs around the time of PHV (Faigenbaum, 2000). It is advisable that, during this period, the coach will be required to monitor load and technique carefully as improper technique combined with heavy loads lifted during this period may increase the possibility of injury. The Long term athlete development plan ‘Canadian Sport for Life’ (Canadian Sport Centres, 2007) gives some guidelines for implementing strength training based on Peak Strength Velocity (PSV). They suggest that peak strength velocity for girls comes shortly after PHV at the onset of menarche, while for boys it occurs 12-18 months after PHV. This is considered the optimal ‘window of trainability’ for strength as hormone production increases dramatically while growth subsides.
Having trained athletes for a variety sports over the last 20 years, I can tell you that muscle hypertrophy is not something that can be rushed or even predicted. It is a common occurrence to witness the tall, skinny teenage boy in the weights room at the local rec centre lifting a weight that is way too big, through a restricted range of motion and with poor technique that results from excessive overload, with the belief that this will increase his size. Then he has a Big Mac afterwards (or nothing at all) to recover. And he probably has a giant tub of creatine at home.
The reality is that increases in muscle size (hypertrophy) will occur when the athlete’s hormonal profile allow it AND when the athlete has been taught effective training, recovery and nutrition interventions. The primary benefit of strength training for pre-adolescent children seems to be neural adaptations whereby motor unit recruitment, intra-muscular coordination, muscular activation and firing are enhanced (Faigenbaum et al. 2009; Faigenbaum, 2000) resulting in strength gains. Therefore, the groundwork for gains in muscle size can be established before and during puberty. Doing this will expedite gains once the athlete is past the growth spurt as motor control is established.
It’s also important to recognise the genetic variance in body types, referred to as ‘somatotype’. Certain body types lend themselves to success in certain sports. For example, ‘ectomorphs’ are long and lean and carry less body fat. Mesomorphs are generally more muscular. Somatotype will have an effect on how muscular an athlete will become through strength training. Some individuals struggle to gain muscle despite disciplined training practise. Others get big if they so much as look at a weight. Fortunately, there is much more to strength development that just building bigger muscles (otherwise body builders would be world-class athletes). Also, successful ski racers come in no particular size and shape, unlike high jumpers or marathon runners.
The guidelines below are from the Australian Strength and Conditioning Association:
Training any athlete follows a set of basic principles and should be progressed in a similar way regardless of age – this starts with the development or core / hip strength and mobility developed through body weight / lighter loads and full range of movement. The athlete works on their foundation (core / hip / shoulder stability + mobility) while developing technique in the bigger lifts. Strong arms and legs are useless to an athlete unless they have a strong core through which to transmit force. As the athlete moves from their growth spurt to full stature, maximum strength type work can be achieved provided the foundation has been laid early on. This approach leads to long term success. More challenges are presented when the athlete grows rapidly – loss of flexibility and coordination are typical amongst adolescent athletes.
It is also important to realise the transfer of work you do in the gym to the ski hill. Although young athletes tend to follow more generic programs, the principle of specificity should be followed for young skiers in strength programs:
-A greater emphasis on lower extremity strength
-An emphasis on eccentric control (e.g. lowering phase of the squat).
-An emphasis on developing explosive movement (e.g. plyometrics progressions)
-Develop unilateral (one-sided) strength as well as bi-lateral strength
-An emphasis on change of direction speed
-An emphasis on torso / hip stability training(esp. anti-rotational ability).
Here are some the principles to follow to keep athletes safe and progressing:
-Spend a lot of time on a progressive warm up that prepares them to lift. Mine usually takes 30-40 mins.
-Progressive overload: Increase the resistance every 1-2 weeks in small increments. Demand that the athlete do every rep with perfect form and the prescribed range of movement. With any athlete who is either pre-adolescent or in the growth spurt, I don’t go below 6RM.
-Supervise your athletes! You have to watch them like a hawk. Explain why doing a half squat with poor form is detrimental. Teach them gym etiquette.
-Variety: change the program every 3-6 weeks to promote new adaptations. You need to give them time to learn exercises and execute them properly before you introduce any overload.
-Teach them safety techniques such as use of racks, collars and spotting.
All for now,