Research evidence continues to define the unique health- and performance-related benefits of resistance exercise for children and adolescents. While the effectiveness of resistance exercise in increasing muscle strength and motor skill performance has been demonstrated repeatedly, current scientific evidence indicates that the right “dose” of resistance exercise can enhance physical performance in young athletes and reduce the risk of developing cardiometabolic disease. The papers discussed in this commentary add to our understanding of the potential benefits of youth resistance exercise by defining dose-response relationships for key training variables, exploring sex-specific adaptations to this type of training, and examining the relationship between muscular strength early in life and cardiometabolic risk later in life. Noteworthy is the identification of unique, sex-specific thresholds for normalized strength to detect high risk cardiometabolic phenotypes in youth. New insights indicate that stronger boys and girls will be better prepared for sport and for life.
Avery D. Faigenbaum
The good news is that a growing body of evidence recognizes resistance training as foundational to long-term physical development. Original research and reviews published in 2017 conclude that early exposure to developmentally appropriate resistance training can improve markers of health, increase muscular fitness, enhance physical literacy, and reduce the risk of injury in young athletes. Although the papers discussed in the commentary add to our understanding of the pleiotropic benefits of youth resistance training, they also raise concerns. As measures of muscular strength and power have been found to track from childhood to adulthood, the bad news is that youth with low levels of muscular fitness tend to become weak adults who are at increased risk for functional limitations and adverse health outcomes. Furthermore, global participation in youth resistance training is falling far short of public health recommendations, and these ugly trends will likely impact the health and well-being of future generations. A change in current attitudes and common practices is urgently needed to educate parents, practitioners, and clinicians about the potential benefits of resistance training for all children and adolescents, not only young athletes.
Avery D. Faigenbaum
Jim Wilcox, Rich Larson, Kevin M. Brochu and Avery D. Faigenbaum
The purpose of this investigation was to determine whether the performance of explosive-force movements before bench-press exercise would improve 1-repetition-maximum (1RM) strength.
Twelve male college athletes participated in 3 testing sessions separated by at least 5 days of rest. During each testing session, the 1RM was assessed on the bench-press exercise. After a general warm-up, subjects performed a specific warm-up that consisted of submaximal sets with increasing loads on the bench-press exercise before attempting a 1RM lift. During the first testing trial, subjects performed a series of 1RM attempts with increasing loads until their 1RM was determined. During the second and third testing trials, subjects performed in a counterbalanced randomized order either 2 plyometric push-ups or 2 medicine-ball (3 to 5 kg) chest passes 30 seconds before each 1RM attempt.
Analysis of the data revealed that 1RM bench-press strength was significantly greater after plyometric push-ups (P = .004) or chest passes (P = .025) in comparison with the first trial (123.8 ± 23.5 kg and 124.0 ± 24.1 kg vs 120.9 ± 23.2 kg, respectively).
These data suggest that an acute bout of low-volume, explosive-force upper body movements performed 30 seconds before a 1RM attempt might enhance bench-press performance in athletic men.
Avery D. Faigenbaum, Laurie Milliken, Lucas Moulton and Wayne L. Westcott
The purpose of this study was to compare early muscular fitness adaptations in children in response to low repetition maximum (LRM) and high repetition maximum (HRM) resistance training. Twenty-three girls and 20 boys between the ages of 8.0 and 12.3 years (mean age 10.6 ± 1.3 years) volunteered to participate in this study. Children performed one set of 6 to 10 RM (n = 12) or one set of 15 to 20 RM (n = 19) on child-size exercise machines twice weekly over 8 weeks. Children in the control group (n = 12) did not resistance train. Maximum strength (1 RM) on the chest press, local muscular endurance (15 RM) on the leg press, long jump, vertical jump, and v-sit flexibility were assessed at baseline and posttraining. The LRM and HRM groups made significantly greater gains in 1-RM strength (21% and 23%, respectively) as compared with the control group (1%). Only the HRM group made significantly greater gains in 15-RM local muscular endurance (42%) and flexibility (15%) than that recorded in the control group (4% and 5%, respectively). If children perform one set per exercise as part of an introductory resistance training program, these findings favor the prescription of a higher RM training range.
Avery D. Faigenbaum, Rhodri S. Lloyd and Gregory D. Myer
Since the publication of the seminal review on youth resistance training by Kraemer and colleagues in 1989, a compelling body of evidence has found that resistance training can be a safe, effective, and worthwhile method of conditioning for children and adolescents. New perspectives for promoting resistance exercise as part of a long-term approach to youth physical development highlight the importance of integrating resistance training into youth fitness programs. Youth who do not enhance their muscular strength and motor skill proficiency early in life may not develop the prerequisite skills and abilities that would allow them to participate in a variety of activities and sports with confidence and vigor later in life. The identification of asymptomatic children with muscular weaknesses or imbalances may facilitate the development of a management plan which should rectify movement limitations and educate children and their families about the importance of daily physical activity.
Jay Hoffman, Nicholas Ratamess, Jie Kang, Gerald Mangine, Avery Faigenbaum and Jeffrey Stout
The effects of creatine and creatine plus β-alanine on strength, power, body composition, and endocrine changes were examined during a 10-wk resistance training program in collegiate football players. Thirty-three male subjects were randomly assigned to either a placebo (P), creatine (C), or creatine plus β-alanine (CA) group. During each testing session subjects were assessed for strength (maximum bench press and squat), power (Wingate anaerobic power test, 20-jump test), and body composition. Resting blood samples were analyzed for total testosterone, cortisol, growth hormone, IGF-1, and sex hormone binding globulin. Changes in lean body mass and percent body fat were greater (P < 0.05) in CA compared to C or P. Significantly greater strength improvements were seen in CA and C compared to P. Resting testosterone concentrations were elevated in C, however, no other significant endocrine changes were noted. Results of this study demonstrate the efficacy of creatine and creatine plus β-alanine on strength performance. Creatine plus β-alanine supplementation appeared to have the greatest effect on lean tissue accruement and body fat composition.
Avery D. Faigenbaum, Leonard D. Zaichkowsky, Wayne L. Westcott, Lyle J. Micheli and Allan F. Fehlandt
The effectiveness of a twice-a-week strength training program on children was evaluated in 14 boys and girls (mean age 10.8 yrs) who participated in a biweekly training program for 8 weeks. Each subject performed three sets of 10 to 15 repetitions on five exercises with intensities ranging between 50 and 100% of a given 10-repetition maximum (RM). All subjects were pre- and posttested on the following measures: 10-RM strength, sit and reach flexibility, vertical jump, seated ball put, resting blood pressure, and body composition parameters. The subjects were compared to a similar group of boys and girls (n = 9; mean age 9.9 yrs) who were randomly selected to serve as controls. Following the training period, the experimental group made greater gains in strength (74.3%) as compared to the control group (13.0%) (p < 0.001), and differences in the sum of seven skinfolds were noted (−2.3% vs. +1.7%, respectively, p < 0.05). Training did not significantly affect other variables. These results suggest that participation in a short-term, twice-a-week strength training program can increase the strength and improve the body composition of young boys and girls.
Nicholas A. Ratamess, Jay R. Hoffman, Ryan Ross, Miles Shanklin, Avery D. Faigenbaum and Jie Kang
The authors aimed to examine the acute hormonal and performance responses to resistance exercise with and without prior consumption of an amino acid/creatine/energy supplement. Eight men performed a resistance-exercise protocol at baseline (BL), 20 min after consuming a supplement (S) consisting of essential amino acids, creatine, taurine, caffeine, and glucuronolactone or a maltodextrin placebo (P). Venous blood samples were obtained before and immediately after (IP), 15 min (15P), and 30 min (30P) after each protocol. Area under the curve of resistance-exercise volume revealed that BL was significantly less than S (10%) and P (8.6%). For fatigue rate, only S (18.4% ± 12.0%) was significantly lower than BL (32.9% ± 8.4%). Total testosterone (TT) and growth hormone (GH) were significantly elevated at IP and 15P in all conditions. The GH response was significantly lower, however, in S and P than in BL. The TT and GH responses did not differ between S and P. These results indicated that a supplement consisting of amino acids, creatine, taurine, caffeine, and glucuronolactone can modestly improve high-intensity endurance; however, the anabolic-hormonal response was not augmented.
Avery D. Faigenbaum, Nicholas A. Ratamess, Jim McFarland, Jon Kaczmarek, Michael J. Coraggio, Jie Kang and Jay R. Hoffman
The purpose of this study was to assess the lifting performance of boys (N = 12; age 11.3 ± 0.8 yr), teens (N = 13; age 13.6 ± 0.6 yr), and men (N = 17; age 21.4 ± 2.1 yr) to various rest interval (RI) lengths on the bench press exercise. Each subject performed 3 sets with a 10 repetition maximum load and a 1, 2, and 3 min RI between sets. Significant differences in lifting performance between age groups were observed within each RI for selected sets with boys and teens performing significantly more total repetitions than adults following protocols with 1 min (27.9 ± 3.1, 26.9 ± 3.9, and 18.2 ± 4.1, respectively), 2 min (29.6 ± 1.0, 27.8 ± 3.5, and 21.4 ± 4.1, respectively) and 3 min (30.0 ± 0.0, 28.8 ± 2.4, and 23.9 ± 5.3, respectively) RIs. Significant differences in average velocity and average power between age groups were also observed. These findings indicate that boys and teens are better able to maintain muscle performance during intermittent moderate-intensity resistance exercise as compared with men.