Strength Training Recommendations for the Young Athlete

In recent years there has been a significant increase in the number of youth participating in organized and competitive sports. Recent studies have supported the participation of preadolescent athletes in strength training to improve health and performance in sports. This article presents the most recent data available to help youth develop a safe and effective strength training program. Variables, such as the recommended rate of progression, the number of sets and repetitions an athlete should perform on each exercise, and how often an athlete needs to workout to avoid loss of strength achieved during a period of strength training are presented.

Over the past two decades, recommendations for strength training in youth have made pivotal changes in response to several studies that have given us new understanding regarding the safety and efficacy of strength training in the prepubescent athlete . Not only have many of the concerns over subjecting the immature skeleton to repetitive loading been resolved , many of the benefits gained from youth resistance training have been substantiated . Strength training has become recognized as an effective method to help youth enjoy sports by decreasing their risk of injury and increasing their chance of success by improving their performance .

Some of the issues that have been addressed in recent studies of resistance training in preadolescent athletes include: the appropriate age for strength training, neuromuscular adaptations, training frequency, number of repetitions, and detraining. The purpose of this article is to present the most current recommendations for strength training in the preadolescent athlete and to provide guidelines that can be used in developing a program that is both safe and effective.

Age

The first consideration involving age is whether strength training is safe for the prepubescent athlete. Much of this concern is related to the open physis. Because cartilage is weaker than bone, many have considered the physis to be the “weak link” in the skeleton. Their concern has been that placing the physis under superphysiologic and repetitive loads would potentially damage the physis, causing it to prematurely fuse, resulting in limb deformity and cessation of limb growth . Micheli noted, however, that the potential for a growth plate injury may actually be less in a child than in an adolescent because the epiphyseal plate of a child is stronger and more resistant to shearing forces.

The few studies that have reported injuries to the epiphyseal plate from strength training have been in adolescents and have been attributed to improper lifting techniques, lifting maximal amounts of weights, and lifts performed without adequate adult supervision . Growth plate injuries have not been reported in any prospective resistance training study that included prescribed training regimens and competent instruction . To protect the growth plate from potential injury, it is recommended that children avoid improper lifting techniques and never perform heavy lifts in an unsupervised setting .

The second issue related to the age a child should begin strength training concerns the efficacy of strength training in children. Because prepubertal boys do not have sufficient levels of circulating androgens to allow for muscles to hypertrophy in response to weight training, in the past it was believed that they could not benefit from weight training.

In 1978, a study by Vrijens questioned whether preadolescents could gain any benefit from weight training . In a group of six boys with an average age of 10.4 years, no significant increase in strength or muscle cross-sectional area was noted after 8 weeks of strength training. When assessed in the light of recent strength studies in children, it seems these findings were likely the result of a low training volume and intensity. In this same vein, a position paper by the American Academy of Pediatrics in 1983 stated that “prepubertal boys do not significantly improve strength or improve muscle mass in a weight training program because of insufficient levels of circulating androgens” .

One of the earliest articles demonstrating the effectiveness of strength training in preadolescents was a study by Sewall and Micheli . In this study 18 prepubescent children strength trained three times per week for 9 weeks. Mean strength increase was 42.9%, compared with an increase of only 9.5% in the control group. Ramsay attributed these gains in strength to adaptations in muscle excitation-contraction coupling, increased motor unit activation, and improved motor skill coordination .

Within the last 10 years, clinical studies and observations have confirmed that a resistance training program of sufficient duration and intensity can enhance the strength of prepubescents beyond what it is as a result of normal growth and development . Although the earliest age that a child should be involved in strength training has yet to be determined, all participants should have the emotional maturity to accept and follow directions, and should understand both the benefits and risks associated with strength training . In a report by Falk , children as young as 6 years old benefited from weight training.

Training frequency

The American College of Sports Medicine recommends that children strength train two to three times per week on nonconsecutive days . Too much exercise may lead to overuse injuries by not allowing adequate time for musculoskeletal tissues to recover between training episodes . Too little strength training may lead to loss of the strength gained during a period of training . To avoid overuse injury, Micheli recommended allowing adequate recovery time between training sessions and not advancing the volume or intensity of training too soon .

Several studies have supported the recommendation of strength training several days per week. Faigenbaum showed that larger strength gains can be made by children performing strength training twice per week as compared with once per week. After 8 weeks of strength training, children (aged 7–12) that trained twice per week had increased their one repetition maximum (1RM) on the chest press by 11.5%, compared with 9% by those who worked out only once per week and 4.4% in the control group. In the leg press, a 24.9% increase in the 1RM was observed by those who worked out twice per week, compared with a 14.2% and 2.4% increase in those who worked out once per week and the control group, respectively. In an additional study by Faigenbaum and colleagues , boys and girls between the ages of 8 and 12 increased their strength an average of 74.3%, compared with 13.0% in the control group after 8 weeks of performing three sets of five different exercises twice per week.

Training frequency

The American College of Sports Medicine recommends that children strength train two to three times per week on nonconsecutive days . Too much exercise may lead to overuse injuries by not allowing adequate time for musculoskeletal tissues to recover between training episodes . Too little strength training may lead to loss of the strength gained during a period of training . To avoid overuse injury, Micheli recommended allowing adequate recovery time between training sessions and not advancing the volume or intensity of training too soon .

Several studies have supported the recommendation of strength training several days per week. Faigenbaum showed that larger strength gains can be made by children performing strength training twice per week as compared with once per week. After 8 weeks of strength training, children (aged 7–12) that trained twice per week had increased their one repetition maximum (1RM) on the chest press by 11.5%, compared with 9% by those who worked out only once per week and 4.4% in the control group. In the leg press, a 24.9% increase in the 1RM was observed by those who worked out twice per week, compared with a 14.2% and 2.4% increase in those who worked out once per week and the control group, respectively. In an additional study by Faigenbaum and colleagues , boys and girls between the ages of 8 and 12 increased their strength an average of 74.3%, compared with 13.0% in the control group after 8 weeks of performing three sets of five different exercises twice per week.

Repetitions

A few studies have examined the influence of exercise volume on strength gains in children. In 1999 Faigenbaum and colleagues performed a study comparing a group of 15 children, strength training using a heavy load and performing one set of six to eight repetitions (low repetition-heavy load), to a group of children training with a moderate load and performing one set of 13 to 15 repetitions (high repetition-moderate load). Participants were assigned to strength train twice per week for a total of 8 weeks. The high repetition-moderate load group was found to have a significantly higher increase in strength (40.9% compared with 31.0%) than the low repetition-heavy load group.

An additional study performed in 2001 by Faigenbaum and colleagues lent support to his previous findings that using a higher number of repetitions with a moderate load led to greater strength gains than training with a heavier load and performing a lower number of repetitions. This study divided children into groups performing four different resistance-training protocols. The first group performed six to eight repetitions on the chest press with a heavy load. A second group performed 13 to 15 repetitions of the same exercise with a moderate load. A third group performed six to eight repetitions of chest press, immediately followed by six to eight medicine ball chest passes (12–16 total repetitions), and a fourth group performing only one set of 13 to 15 medicine ball chest passes. The only groups who improved their strength (using a 1RM chest press strength) after an 8-week training program were the groups who performed a higher number of repetitions and used the chest press as part of their training protocol.

The number of repetitions a child is able to perform often varies between exercises and is most likely the result of differing amounts of muscle mass involved in each exercise . In a study using percentages of the 1RM it was found that the number of repetitions a child could perform at a specific percentage of the 1RM varied between exercises . The number of repetitions that each child could perform at a given percentage of the 1RM was significantly greater when performing the leg press than when performing the chest press.

The method used by Dr. Thomas DeLorme to determine effectual ratios of resistance to repetitions for young military males in a rehabilitation setting is still used today in many training centers . The 1RM was determined each week. The patient then trained at 60% to 70% of the 1RM, while usually closely approximating the 10RM, depending on the lift being performed. Concerns have been raised, however, regarding the safety of performing the one repetition maximum in children.

Perhaps the safest way to determine the number or repetitions that should be performed for each exercise in children is by starting with a relatively low weight that a child can easily lift 13 to 15 times without difficulty, and then increasing the weight until a point where a child is able to perform no more than 15 repetitions, but is able to perform at least 13 repetitions. As the child’s strength increases, the amount of weight he or she is lifting can be increased by 2.5 to 5 pounds until the number of repetitions they can perform is within a set number of repetitions .

Single versus multiple sets

Whether a single set is as efficient in making strength gains as performing multiple sets of the same exercise has been the subject of several studies and meta-analysis in the adult population; however, no studies have been performed specific to the preadolescent athlete. Recent studies in adult populations support greater strength gains when using multiple sets rather than single sets, especially after progression occurs and higher gains are desired .

In a study by Rhea and colleagues , young men (age 21, plus or minus 2 years) were randomized to groups performing one or three sets of leg presses and bench presses, three times a week for a period of 12 weeks. Using 1RM testing, those in the group performing three sets of each exercise made 30% greater strength gains in the leg press and 13% greater strength gains in the bench press than those performing only one set of each exercise. Similar findings were seen in a study performed in a group of women performing either one or three sets of a variety of exercises for a period of 6 weeks.

Currently, the National Strength and Conditioning Association supports preadolescents performing one to three sets of a variety of single- and multijoint exercises . Increasing the number of sets performed is another way to influence an athlete’s strength progression. Further studies conducted in preadolescents may provide additional information regarding whether the number of sets performed on each exercise effects strength gains.

Rest period between sets

The time an athlete should rest between sets to get the most out of his or her training has been the subject of various studies in adult populations . No study in preadolescents has specifically addressed this subject.

In a study by Richmond and Godard , 28 men performed two sets of bench presses to volitional exhaustion. Rest periods of 1, 3, and 5 minutes between sets were used on three separate testing days. No difference in total work load (repetitions × weight) was found between the 3- and 5- minute rest periods, but the work load decreased significantly if the rest period was decreased to 1 minute.

Hill-Haas and colleagues , found a greater increase in strength (45.9% versus 19.6%) after a 5 week strength training program in women given an 80-second rest interval between sets, compared with those given a 20-second rest interval.

Although trying to manipulate as many variables as possible to get as much as possible out of a strength training session may be a prudent use of time, structuring a workout program too rigidly may discourage a young athlete from long term participation in an activity that can be both fun and rewarding.

Mode of training

Several different types of exercises have been used to perform resistance exercises in children. Some that have been used include free weights, weight machines, body weight exercises (ie, push-ups or pull-ups), rubber tubing, medicine balls, and plyometrics.

It is important to consider the varying abilities of the children that will be participating when choosing the type of exercise to include in a strength training program. Some children may not be able to exert enough strength to successfully perform certain body weight exercises, such as push-ups or pull-ups. The preadolescent athlete may not be big enough to perform certain movements on adult sized equipment. Child-sized weight machines are available, but they are often difficult to find and can be quite expensive to purchase. Simply adding some extra padding to adult size equipment may resolve this discrepancy.

Free weights may be a good option for children because they are inexpensive, widely available, and allow for more variability between loads than some adult sized weight machines. They do, however, require close supervision to avoid injury from improper use. When free weights are chosen as a strength training modality, the authors feel that barbells are safer for children than dumbbells. Barbells promote better form and do not lend themselves as easily to the swinging, bounding movements sometimes common to lifting with dumbbells.

Among the several strength training exercises that can be chosen to include in a strength training program, a focus should be made on including exercises that strengthen the “core” of a young athletes body (low back, abdomen, and hips) . Examples of core strengthening exercises include sit-ups, back extensions, and exercises rotational exercises performed with a medicine ball . Including core exercises in a strength training program can help an athlete avoid injuries by strengthening the areas most commonly injured in youth sports .

Among the different types of exercises to include in a strength training program are exercises that involve single joints and those that involve multiple joints. Single-joint exercises are those that target a specific muscle group. Examples of single-joint exercises include leg-extensions and bicep curls, where only a single joint is involved in the movement. Examples of multi-joint exercises include the squat ( Fig. 1 ) and bench press. Although multi-joint exercises are technically more difficult to master, they provide additional benefit to the athlete by incorporating coordination, balance, and proprioception into the workout program. That having been said, great care and close supervision with double spotting should be used when children perform squats. If this is not possible, machine leg presses are preferable and safer.