SMITH'S FITNESS
Why Two Speeds
Your Bronco speed is not your running speed — here's the maths.
Your Bronco speed is not your running speed — here's the maths.
When professional rugby league players were measured on both, maximal aerobic speed on a treadmill was 0.75 m/s faster than their Bronco average speed. That gap is the price of 29 turnarounds — roughly 17% of your speed.
So: run in a straight line, use MAS, because there are no turns to pay for. Run shuttles, use BAS, because BAS was measured with the turns already in it.
Programs that treat 1200 ÷ your time as your MAS under-prescribe every straight-line rep by about 19%.
BAS = 1200 ÷ your Bronco time in seconds
MAS = BAS + 0.75
Straight-line target = distance ÷ (MAS × %) + 1 s per turnaround
Shuttle target = distance ÷ (BAS × %)
| Population | Bronco |
|---|---|
| Super Rugby men — all positions | 5:11 |
| Super Rugby men — backs | 4:57 |
| Super Rugby men — forwards | 5:21 |
| Super Rugby women — all positions | 6:19 |
| Super Rugby women — backs | 5:52 |
| Super Rugby women — forwards | 6:38 |
Weakley et al. (2026), Journal of Strength & Conditioning Research 40(5) — 462 elite athletes, 1,668 tests, 10 years. Correction factor from Bennett et al. (2024), PLoS ONE 19(7):e0306062. Typical error from Deuchrass et al. (2019).