Guidance for Strength Training in the Pre-adolescentA Case Based approach in the pediatrician’s office Teri McCambridge, MD, FAAP Assistant Professor of Pediatrics Johns Hopkins School of Medicine
Teri Metcalf McCambridge • A. I have no relevant financial relationships with the manufacturer's) of any commercial product(s) and/or provider of commercial services discussed in this CME activity. • B. I do not intend to discuss an unapproved/investigative use of a commercial product/device in my presentation.
Case I: • 9 year old male football player wants to begin a strength training program, but his mom has heard he will not demonstrate increases in strength until puberty and that it is dangerous. • What do you advise?
Appropriate age to begin strength training? • Attained the ability to follow rules • Achieve balance and postural control (age 7-8) • Proficiency in their sport • Common sense • Lack of androgenic hormones? • Whose idea? • What’s the motive? Richard Santrak
Is it efficacious?Why the controversy? • Initial Studies revealed: • No increase in muscle strength • No increase in muscle cross-sectional area • 1983 AAP Statement Committee on Sports Medicine “Pre-pubescent boys (tanner stage 1-2) demonstrate no significant increase in strength or muscle mass because of lack of androgens” Vrijens J Med Sport 1978; 11:152-158
Deficiencies of early research • Children naturally increase strength as they grow and mature, must have adequate controls • Studies were short duration • Studies evaluated low intensity training volumes (Sets x repetitions x load) • Overall inadequate studies
Recent Research Demonstrates Significant Gains: • Sewall, L, Micheli LJ: J Pediatric Orthop 1986;6:143-146 • Weltman A, et al. Med Sci Sports Exerc 1986; 18:629-638 • Faigenbaum, AD, et al. Pediatr Exerc Sci. 1993; 5:339-46. • Faigenbaum, AD,. et al. J Strength and Cond Res 1996; 10(2):109-114 • Falk B, et al. Sports Med.1996;22(3):176-186 • Faigenbaum AD J Strength Cond Res 2001;15:459-465. • Strength gains between 36%-74.3% • No effect on flexibility • No effect on vertical jump
Mechanism of Strength Gains? • Not Muscle Hypertrophy • As measured by CT scanning • Occurs in boys and girls equally • Strength gains dependent on increased motor unit: • Activation/recruitment • Coordination • Firing • 8 weeks required Ozmun, J Mikesky A. Med Sci Sports Exerc 1994;26:510-514
Current AAP Policy Statement: • 2001-”Studies have shown that strength training, when properly structured with regard to freq, mode, intensity, and duration increases in strength in pre-adolescents without muscle hypertrophy” • 2008-”Agree with above and Olympic weight lifting may be safe in closely supervised settings but more research is needed to recommend.”
Is it Safe?Why the concern? • Initial NEISS reports • 1979 half of 35, 512 weight lifting injuries involved 10-19 year olds • 1987 report revealed 8590 children 14 and under were treated in emergency department with weight lifting injuries • 1991-1996 20k-26k equipment associated injuries occurring annually
Problems with using this data to determine safety: • Does not distinguish between resistance training and competitive weight lifting • Information is based on patient report of injury • Does not distinguish between supervised and unsupervised injuries • Does not report if weights were utilized properly
Is it Safer than some Sports? • Study by Hamill suggests strength training is safer than participation in: • Soccer • Basketball • Football • General play Hamill B. J Strength Cond Res 1994;8:53-57
Recent literature: CPSC NEISSAccidental weight training Injuries Myer GD. J Strength Cond Res 2009; 23(7) 2054:2060
Considered Safe: • Proper Equipment • Proper Form • Proper Supervision • Certified or Trained individual • Ratio of Adult to Student (1:10)
Health Risks--Stunted Growth? • Concerns • Arouse out of studies in Japan • Children performing heavy labor • Resulted in “stunted growth” • Nutritional deficiencies or labor? • Data of well controlled/designed studies no effect on growth or epiphyseal plates
CASE 1 • Can the 9 year old begin a strength training program? • What’s the reason? • Is there supervision? • Is it necessary? • Is it appropriate?
Case 2: • 14 year old tanner Stage 3 male basketball player wants to begin the “clean and jerk” and “snatch” • What is your opinion of these lifts? • Should this be a bigger concern?
Strength Training/ Resistance training • “Specialized method of physical conditioning that is used to increase one’s ability to exert or resist force”
Methods? • Free weights • Weight Machines • Weight plates • Hydraulics • Bands/Balls • Body weight • Kettle balls
Other Forms: • Brief Discussion: • Competitive Weightlifting (Olympic) • Competitive sport that involves maximum lifting ability • Lifts: Snatch and Clean and Jerk • Minimal Discussion • Power Lifting • Competitive sport involving maximum lifts • Dead lift, squats, and bench press • Body Building • Competition that judges muscle size definition, and symmetry
Plyometrics (Stretch-Shortening Cycle) • Safe and worthwhile method of conditioning • Typically includes hops or jumps • Cautious of too many repetitions
Is Olympic Weightlifting Safe? • Data suggests safety in well supervised settings • Study at the USA Weightlifting Development Center Byrd R, Pierce K, et al. Sports Biomech 2003;Jan 2(1): 133-40
The AAP’S Policy (2008) • Safe in Well controlled studies, emphasizing proper technique • Do not yet recommend for general population • Concerns regarding improper technique and injury risk • Impetus for childhood involvement?
What’s Really Happening • Survey of HS S&C coaches • 38 of 128 Responded • 37 of 38 use Olympic –Style lifting Duehring MD, J Strength Cond Res 2009; 23(8)2188-2203
Severe Injuries associated with improper Olympic lifting • Bilateral Distal Radial and Ulnar Fractures • Disc Herniation • Spondylolysis and Spondylolisthesis • ASIS pelvic avulsion fracture • Scaphoid fracture • Death
CASE 2 • What’s the difference between strength training and competitive weightlifting? • Why the distinction when recommending children’s participation?
Case 3: • A 12 year old female soccer players’ parents wants to know if strength training can: • Prevent an ACL tear? • Improve sports performance in the pre-adolescent? • Provide permanent strength gains once a program is completed?
Injury Prevention with Strength Training? • Less Shoulder pain in Adolescent Swimmers Dominquez, Swimming Medicine IV 1978: 105-109 • Decreased incidence and severity of knee injury with preseason training Cahill B, Griffith E. Am J Sport Med 1978; 6:180-184 • ACL prevention with Plyometric jump training program Hewett, TE, et al. Am J Sport Med 1999; 27:699 More Evidence to follow?
Benefits? Anaerobic Power? • 30 Prepubescent male athletes • 12 week strength training with free weights and machines. 3x/week • Outcome variables: vertical jump, 40 yd dash, and Wingate test • Results: Vertical jump improved, but no other measures of anaerobic power Hetzler, RK, Coop D, et al. J Strength Cond. Res. 1997; 11(3):174-181
Sports Performance? • Inconclusive evidence • Evidence for improved • vertical jump • long jump • sprint speed • Medicine ball toss • Translation into improved performance is inconclusive • Limited evidence improvement Hoffman JR (football) J strength Cond Res 2005; 19(4):810-815 Faigenbaum A. Phys Edu 2006; 63: 160-67. Christou M. (soccer) J Strength Cond Res 2006 20(4), 783-791
Strength Training and Detraining • Recommend Frequency in children 2x/week training • Detraining • Loss of strength about 3% week • Despite athletic participation Faigenbaum AD, et al. Res Quarterly Exercise Sport, 2002; 73(4): 416-424. Faigenbaum, AD, et al. J Strength and Cond Res 1996; 10(2):109-114
CASE 3 • Strength training is not the “end-all-be-all” for sports • Just one component of various training methods • “Prehabilitation” strengthening may have some promise • Performance benefit lacking at this time
Case 4 • A 15 year old, with a past medical history of Childhood leukemia, wants to begin a strength training program—Is there any evaluation required prior to participation?
Athletes requiring clearance prior to participation • Uncontrolled severe hypertension • Previous treatment with anthracycline chemotherapeutic agents • Uncontrolled seizure disorder • Underlying neuromuscular disorder (Cerebral Palsy, etc.)
Cardiology consultation recommended if history of: • Hypertrophic Cardiomyopathy • Moderate-Severe pulmonary hypertension • Uncontrolled Hypertension • Marfan’s Syndrome with a dilated aorta
Aortic Root dilatation in Elite Strength Trained athletes • 100 Elite Strength trained athletes • Age mean 22.1 + 3.6 years • 128 healthy age and height matched control • Results Aortic root diameters were significantly greater in all 4 locations of measurement, with progressive enlargement noted based on duration of high intensity lifting. Am J Cardiology 2007: 100:528-530
Past Medical History:Childhood Leukemia/Oncology • Patient’s treated with high dose (500 mg/M2)anthracycline therapy are at risk for acute cardiac decompensation with initiation of weight training • Cardiology/Oncology input required prior to program initiation Steinherz, Laurel, et al. Cardiac Toxicity 4 to 20 years after completing anthracycline therapy Jama 1991; 266 (12): 1672-1677.
CASE 4 • Usual preparticipation guidelines exist • Be aware of new recommendations, such as for young cancer survivors
Case 5. • The parents of a 14 year old want to enroll their child in a strength training program. They bring in a list of questions including: • Guidance on a proper strength training program • How to evaluate a personal trainer’s credentials • List of respected sports training facility in your area
Initiating a Weight Training Program What you need to know! Guidelines have been established by The AAP, AOSSM, and NSCA
General Recommendations(program) • 10 minutes dynamic warm-up and cool down • Program should include 1-3 sets of 6-15 reps of 6-8 exercises • Include all muscle groups and a full ROM at each joint • Focus on technique and proper form • Recommend 2-3 non-consecutive training sessions/wk for 20-30 min • Increase resistance gradually • Program varied over time . Faigenbaum AD. Clinics in Sport Med; 19 (4): 2000
Examples of exercises to incorporate into a beginning program • Single joint • Leg extension • Multi-joint • Squats • Plyometrics • Squat jumps, medicine ball chest passes • Core strengthening • Sit-ups, back extensions
Means of progressing a program • Increase the resistance • Generally 5-10% increase in training load • Increase repetitions • Increase number of sets
Recommendations for Parents evaluating a program • Qualifications of Instructor • Student : Teacher ratio • Modes of strength training that will be utilized • Evaluate weight stack increments (1-5 pounds in children) • Weight machine sizes • Will 1 weight rep max be used • Performance of Olympic or power lifts
Special Recommendations forYouth Strength training • Consider decreasing training volume and intensity during rapid growth • Emphasize flexibility • Stress importance of proper lifting techniques not amount of weight lifted • Controlled movements • Proper breathing • Recommend against competitive weight lifting, power lifting, and body building until skeletally mature
Evaluating Strength Training Credentials • Is the program NCCA certified? • Do they require re-certification and CEU’S? • Are there minimum requirements? • Is the exam proctored and does it have a practicum? • How long have they been certified?