The effect of XC-running race Lidingöloppet on determinants of performance

Elias Rapp¹Francesco Laterza^2,3Vincenzo Manzi²Ferdinand Von Walden⁴Daniele A. Cardinale^5,6*

• ¹Gymnastik- och idrottshogskolan, Stockholm, Sweden
• ²Universita Telematica Pegaso, Naples, Italy
• ³Universita degli Studi di Verona, Verona, Italy
• ⁴Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden, Stockholm, Sweden
• ⁵Swedish School of Sport and Health Sciences, Stockholm, Sweden
• ⁶Karolinska Institutet Institutionen for fysiologi och farmakologi, Stockholm, Sweden

Aim: This study aimed to investigate determinants of running performance in a cross-country running race and to examine whether running economy and biomechanics are affected. Moreover, we analysed if the magnitude of change in running economy related to the change in biomechanics, performance and fitness measures. Method: Thirteen runners (12 male, 1 female) with an average 10 km personal best time of 36:46 ± 3:17 (min:s) participated in the 30 km cross-country race, Lidingöloppet. Assessments of submaximal and maximal running physiology, biomechanics and anthropometry were conducted before and immediately after the race. A multiple linear regression model was conducted to explain performance variance. Pearson's correlation analyses examined the relationships between performance and pre-test variables, as well as between changes in running economy and both pre-test fitness measures and changes in biomechanics. Paired Student's t-tests were used to compare pre-and post-race values. Results: Performance was best explained by a model including oxygen uptake at lactate threshold, fat utilization and allometrically scaled running economy (R2=0.918, adjusted R2=0.887, F=29.7, p<0.01). Race performance also correlated with maximal oxygen uptake (VO2max, r=-0.776, p=0.003), fat mass (r=0.646, p=0.032) and velocity at VO2max (vVO2max, r= -0.853, p<0.01). Oxygen cost of running increased (201.8±14 vs 208.4±9.3 mL·kg-1·km-1, p=0.041) whereas respiratory exchange ratio (0.91±0.04 vs 0.85±0.05, p<0.01) and body mass (69.2±7.5 vs 67.6±7.7 kg, p<0.01) were decreased post-race. Energetic cost of running (0.997±0.076 vs 1.015±0.052 kcal·kg-1·km-1, p=0.192) and all biomechanical measurements including cadence, contact time, overstride, vertical displacement and vertical force were unaffected by the race. The magnitude of change in running economy was only related to pre-test running economy (r=-0.749, p=0.003) but not to performance (r=-0.440, p=0.132), other pre-test fitness measures or any changes in biomechanics. Conclusion: The best performance prediction model included oxygen uptake at estimated lactate threshold, fat utilization at submaximal running and allometrically scaled running economy. Oxygen cost of increased post-race, likely due to increased fat oxidation, despite decreased body mass. No changes in biomechanics were observed and changes in running economy could not be explained by changes in biomechanics. Aerobic fitness, anthropometry, and performance were not associated with changes in running economy.