Author(s): TIERNAN, C., DARRAGH, I., NOLAN, D., Institution: UNIVERSITY OF LIMERICK, Country: IRELAND, Abstract-ID: 2429

INTRODUCTION:
Maximal aerobic speed (MAS) is a popular measure of aerobic fitness [1] that is commonly measured with a 1.2km continuous time trial. This study compared estimates of MAS derived from standard and reverse 1.2-km shuttle tests (Bronco) to a 1.2-km continuous looped time trial in collegiate team-sport athletes.
METHODS:
Fifty (35 female, 15 male) collegiate field-sport athletes (mean ± SD; age: 20.2 ± 2.2years, height: 170 ± 8.3cm, body mass: 69 ± 8.8kg) volunteered to participated in the study. All testing was conducted on the same 4G astroturf surface with a standardised warm-up. Participants performed three running-based 1.2km fitness tests (standard Bronco, starting at 20m, reverse Bronco [BRONrev] starting at 60m, and continuous looped time trial [TT]) in a randomised order. MAS scores were derived from test times using distance–time relationships. Correction factors (adjusted and unadjusted) were applied to the Bronco protocols to account for changes of direction and were assessed for efficacy. Data were analysed using a linear correlation between the Bronco and BRONrev estimates of MAS, and TT estimated MAS. Simple linear regression was used to predict TT MAS from both Bronco variant MAS estimates.
RESULTS:
A strong positive correlation was found between unadjusted Bronco/BRONrev (R = 0.93, adjusted R2 = 0.85); 0.7s adjusted Bronco/BRONrev estimated MAS (R = 0.93, adjusted R2 = 0.86) and 1s adjusted Bronco/BRONrev estimated MAS (R = 0.93, adjusted R2 = 0.86) and TT estimated MAS score. All Bronco/BRONrev variants estimated MAS scores correlated to TT estimated MAS with similar magnitude. The results of a simple linear regression model using unadjusted Bronco/BRONrev estimated MAS score to predict time-trial estimated MAS score produced a significant result (β = 1.2, adjusted R2 = 0.85, p < 0.01). No significant interaction was found between bronco test types and the model’s capacity to estimate time trial MAS score (β = 0.09, p = 0.34).
CONCLUSION:
There was a strong association found between both Bronco protocols and TT MAS scores. These findings suggest that both Bronco protocols provide a valid field-based surrogate for estimating MAS in collegiate field-sport athletes. While both formats offer a robust estimate of aerobic capacity, the application of correction factors are required to use shuttle-derived scores interchangeably with continuous 1.2-km TT MAS scores. Overall, these findings support the use of both Bronco tests to calculate MAS scores, which may aid coaches to individualise the prescription and monitoring of running-based training intensities.

1) Nurwulan, I. et al. 2025. Effectiveness of Interval Training Using Maximum Aerobic Speed (MAS) to Improve Aerobic Capacity. JPEHS, 12(1), 187-193.