Camber Differentially Affects Trained Runners At Marathon Pace, Improving Running Economy In Some Individuals

Roads are cambered to promote water drainage, with a suggested camber of 2-4%, with maximum cambers of 8-10% on curves. This may influence running economy during a marathon, potentially leading to decrements in performance. PURPOSE: This study was designed to determine whether camber affects running economy at marathon pace. METHODS: Twelve trained runners (age = 29.5 ± 13.3 years, height = 179.6 ± 5.2 cm, weight = 71.2 ± 8.3 kg, VO2 = 61.3 ± 7.8 mL/kg/min, 30.0 ± 17.2 miles/week (last 4 weeks)) performed a graded exercise test to failure to determine speed at ventilatory threshold (VT). Following a 15 min rest, participants ran for 5 minutes at three cambers (0%, 3%, 6% - obtained by lifting the right side of the treadmill) in a counterbalanced order, 1mph below VT at a 1% grade, while wearing a standardized shoe (Brooks Ghost 15). Metabolic (VO2, Heart Rate, Ventilation (VE)) and perceptual measurements (RPE (Borg 6-20)) were collected during the last 2 minutes of each trial. RESULTS: As a group, there were no differences in any of the metabolic data, though there was a significant decrease in RPE at a 3% camber (13.4 ± 1.8, p < 0.05) as compared to a 0% camber (13.8 ± 1.6). As a group, there was a 0.7% decrease in VO2 at 3% (p = 0.25), and a 0.83% decrease at 6% (p = 0.41) as compared to running at a 0% camber. However, post-hoc analysis revealed two groups of runners, those that had improved economy (n = 6) while running on a camber, and those who were relatively unaffected. For runners who improved, economy at 3% and 6% camber were decreased by 2.43 ± 0.91% (3.60 ± 0.36 L/min, p < 0.01) and 2.68 ± 2.8% (3.60 ± 0.39 L/min, p = 0.07) respectively from a control, 0%, camber of 3.70 ± 0.39 L/min. Ventilation was likewise decreased by 4.5% while running on a 3% camber (78.4 ± 5.4 L/min, p < 0.05) and 3.7% while running on a 6% camber (79.1 ± 6.2, p < 0.05) as compared to a 0% camber control (82.2 ± 7.0 L/min). CONCLUSION: Running on a camber doesn’t decrease running economy and may in fact be beneficial for some runners. This suggests that runners don’t need to stay on the crown/flat part of the road and they can run on cambered roads during races without metabolic decrements. Further research is needed to understand how metrics related to symmetry, injury potential, and neural control are related to the kinematic and EMG changes that occur with changes in camber.