Talent & Trainability: Are youths responsive to training?

Transcription

1 Talent & Trainability: Are youths responsive to training? Jon Oliver, PhD Reader in Applied Paediatric Exercise Science Start with the obvious Children are not mini-adults Pertinent Questions - What is the pathway to becoming an adult? What are the implications for training? 2 1

2 Percentage of Total Growth Achieved 27/11/ Scammon s Curves Rapid neural development Neural Rapid hormone mediated development 20 Reproductive 0 Onset of puberty Age (years) 3 Absolute Fitness Development Onset of puberty 2

3 Popular Theories Trigger Hypothesis Prior to the trigger of puberty the effects of physical conditioning will be minimal or will not occur at all (Katch, 1983) Sensitive Periods and Windows of Opportunity Biological systems are most sensitive to external stimuli (e.g. diet, exercise) when they are experiencing periods of rapid natural development. (Scott, 1986; Viru et al., 1999) 5 Aerobic n = 22 studies fitness on children training and adolescents reviews Male: Prepubertal = 6.1% Female: Prepubertal = 6.9 % Baseline fitness : Low = 5.9%, High = 2.9% Programme design Frequency: > 3 session/week = 5-6% Duration: < 30 min = 4.5% > 30 min = 8.2% Intensity: 80% HR max = 4-5% > 80% HR max = 4-8% All-out sprint = 8% 3

4 Generic Training All studies = 2-28% Utilised a high-intensity = 4-28% Elite population = 4-7% Periods of high-intensity effort are key Sport-Specific Training All studies = 1-17% Gains for pre, circa and postpubertal Aerobic fitness should be trained throughout development and not aligned to specific periods of maturation Systematic Strength Training Reviews Payne et al. (1997) Behringer et al. (2010) n = 28 studies, n = 42 studies ES range for younger/older, Overall ES = 1.12 pre/post PHV, girls and boys Prepuberty ES = 0.89 these Intra/postpuberty findings do not = support 1.91 Katch's trigger hypothesis as it relates Programme to muscular Design endurance Duration, and strength r = 0.28 Frequency, r = 0.26 Intensity, r =

5 Transference of Strength Training Gains Behringer et al. (2011) n = 34 studies Combined ES = 0.52 Non-Athlete ES = 0.60, Athlete ES = 0.40 Continuous Moderator Variables Age, r = Intensity, r = 0.38 Strength Training & Maturation Vrijens (1978) Strength gains varied with maturity and muscle groups Pfeiffer & Francis (1986) No maturation effects in boys Lillegard et al. (1997) No maturation or gender effects Meylan et al. (2014) Possible to likely that training gains smaller and subside quicker pre-phv 5

6 10 m Sprint time % Improvement % Improvement 27/11/2015 Systematic Speed Training Review Rumpf et al. (2012) n = 17 studies (2 sprint training studies, 6 strength and power studies, 4 plyometric studies 5 combined training studies) Individual Responses to Training Plyometric Training Pre-PHV Post PHV Strength Training (data from Lloyd et al., in press) 6

7 % Improvement 27/11/2015 Individual Responses to Training 5 4 Pre-PHV Post PHV Combined Training Youth Physical Development Model All components of fitness are responsive to training regardless of age or maturation Underpinning adaptations may vary with age and maturation Relative importance of training a component of fitness may change with maturation and training age (Lloyd and Oliver 2012) 7

8 How much training is needed to become an elite sports person? 10,000 Hours????? Equates to 20 hours per week of deliberate practice/training for 10 years 8

9 Incidence ratio (per player, per season) 27/11/2015 Accumulated Training Figure X Accumulated training in elite and near-elite athletes (based on data from Moesch et al., 2011) An Example from Football The UK Football Model (Elite Player Performance Plan) Status U5-U11 U12-U16 U17-U21 Total Hours Category 1 4 rising to 8 12 rising to Up to 8,500 Injury incidence per player per season: Price et al. (2004) = 0.40 Read et al (2015) = U11 U12 U13 U14 U15 U16 U18 9

10 Training Volumes Figure Y Weekly training loads in elite youth soccer (data from Wrigley et al., 2012) Growth Related Injuries Figure Z Incidence of two growth-related injuries in academy youth football (Price et al., 2004) 10

11 Growth and Maturation Kemper et al. (2015) Growth rate >7.2 cm/y increases risk of injury Figure A Growth rate of stature used as used to identify important events during maturation Overtraining and Burnout ~ 30% of youth athletes experience nonfunctional overreaching, staleness, overtraining and/or burnout (Kentta et al, 2001; Matos et al, 2011; Raglin et al., 2000) 11

12 Symptoms of overtraining in youths Adapted from Matos et al. (2011), symptoms in order of prevalence Physical Symptoms Psychological Symptoms Loss of Appetite Apathy Traditionally overtraining Feel intimidated is diagnosed by opponents as a Bad mood persistent long-lasting (i.e. weeks or Often sad months) decrement in performance Often get injured Frequently tired Inability to cope with training loads Frequent respiratory infections Lack of confidence in future Heavy and stiff muscles Sleep problems Lack of confidence in competition Do not enjoy training In children there appears to be more of a psychological component related to burnout and attrition 12

13 Long-term benefits of systematic training Table 1. Physical development of academy soccer players and school boys over a three year period, with change scores adjusted for baseline fitness and maturity (Wrigley et al., 2014) Academy School boys Difference CMJ (cm) m (s) m (s) agility Repeated sprints (s) Yo-yo (m) Summary Youths are responsive to training irrespective of age and maturation In addition to maturation, baseline fitness, training history and programme design will influence responsiveness and adaptations to training The success of current practices in training youth athletes may be questioned given Varied Individual responsiveness High rates of injury High rates of overtraining and burnout The long-term added value of training programmes to enhance development 13