# Effect of somatic maturity on the aerobic and anaerobic adaptations to sprint interval training

PMID: 32378353
Journal: Physiological reports
Published: 2020 May
Authors: Beyer KS, Stout JR, Redd MJ, Baker KM, Church DD, Bergstrom HC, Hoffman JR, Fukuda DH

## Question

Do youth male athletes at different stages of somatic maturity adapt differently to a 4-week cycling sprint interval training program?

## Summary

This quasi-experimental study tested 4 weeks of all-out cycling sprint interval training in male youth multisport athletes grouped by maturity status. More mature, post-peak-height-velocity athletes improved both aerobic and anaerobic outcomes, peripubertal athletes improved repeated sprint power only, and prepubertal athletes did not show clear improvements. The protocol was demanding: 20-second maximal cycling sprints against 7.5% body mass with 4-minute active recoveries.

## Population

- Male youth multisport athletes aged 11-17 years, grouped by years from peak height velocity.
- Sample size: 27
- Age: Overall 14.63 +/- 2.33 years; PRE 11.57 +/- 0.57, PERI 14.33 +/- 0.73, POST 16.95 +/- 0.34 years.
- Sex: All male.
- Fitness level: Competitive multisport athletes with at least two sports in the prior year.
- Health status: Medical clearance to play sports within the last year.

## Methodology

- Quasi-experimental pre-post intervention comparing maturity-status groups; no non-training control group.
- 4 weeks, with pre- and post-testing at least 48 hours from SIT sessions.
- Laboratory cycle-ergometer testing and training in a university exercise science setting.

## Protocol

- Youth cycling sprint interval training.
- Modality: Cycle ergometer.
- Work intervals: 20 seconds maximal sprint.
- Recovery: 4 minutes active recovery.
- Sets or repetitions: 4 sprints in session 1, progressing to 7 in session 7, then 4 in session 8.
- Intensity: All-out against 7.5% body mass resistance.
- Session duration: Training table reports total session time from 14 minutes at 4 sprints to 26 minutes at 7 sprints, plus 5-minute warm-up described in text.
- Frequency: 2 sessions/week.
- Program length: 4 weeks.
- Progression: One sprint added each week except the final taper session.

## Outcomes

### Maximal aerobic power
Status: improved
Maximal aerobic power increased across the whole sample regardless of maturity group.

Main time effect p<0.001; baseline 212.61 +/- 57.45 W to post 223.24 +/- 58.90 W.

### VO2peak
Status: mixed
VO2peak increased only in the postpubertal group, not prepubertal or peripubertal groups.

Group x time p=0.033; POST 3.31 +/- 0.43 to 3.54 +/- 0.43 L/min, p=0.003.

### Systemic fatigue thresholds
Status: mixed
GET, VT, and RCP improved in POST, with no changes in PRE or PERI.

Authors report significant increases in POST and no changes in PRE/PERI.

### Repeated peak and mean sprint power
Status: mixed
PERI and POST improved session-average peak and mean power from session 1 to 8, while PRE did not.

PP group x time p=0.035; MP group x time p=0.022. PERI PP p=0.003, MP p=0.009; POST PP p=0.001, MP p=0.012; PRE not significant.

### Prepubertal response
Status: no clear change
PRE participants had no significant aerobic or anaerobic improvements after this 4-week cycling SIT program.

PRE VO2peak p=0.410; PP p=0.169; MP p=0.480.

## Practical Insights

- All-out cycling SIT may not produce the same adaptations across youth maturity stages.
- A 20-second sprint with 4-minute recovery is a low-volume but high-intensity athlete protocol.
- For youth, maturity and training background should shape expectations and programming.

## Limitations

- No non-training control group.
- Small maturity subgroups.
- Male youth athletes only.
- Training heart rate was not recorded.
- Outside sport practices continued during the intervention.

## Safety And Adherence

- Participants required sport medical clearance.
- Six recruited participants did not complete due to scheduling conflicts.
- The article did not report training adverse events or injuries.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/32378353/) (pubmed)
- [DOI](https://doi.org/10.14814/phy2.14426) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7202988/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.