Santos-Concejero, J, Tam, N, Granados, C, Irazusta, J, Bidaurrazaga-Letona, I, Zabala-Lili, J, and Gil, SM. Stride angle as a novel indicator of running economy in well-trained runners. J Strength Cond Res 28(7): 1889–1895, 2014—The main purpose of this study was to investigate the relationship between a novel biomechanical variable, the stride angle, and running economy (RE) in a homogeneous group of long-distance athletes. Twenty-five well-trained male runners completed 4-minute running stages on a treadmill at different set velocities. During the test, biomechanical variables such as stride angle, swing time, ground contact time, stride length, stride frequency, and the different sub-phases of ground contact were recorded using an optical measurement system. V[Combining Dot Above]O2 values at velocities below the lactate threshold were measured to calculate RE. Stride angle was negatively correlated with RE at every speed (p < 0.001, large effect sizes). Running economy was also negatively correlated with swing phase and positively correlated with ground contact time and running performance according to the best 10-km race time (p ≤ 0.05, moderate and large effect sizes). Last, stride angle was correlated with ground contact time at every speed (p < 0.001, large effect sizes). In conclusion, it seems that optimal execution of stride angle allows runners to minimize contact time during ground contact, whereby facilitating a better RE. Coaches and/or athletes may find stride angle a useful and easily obtainable measure to track and make alterations to running technique, because changes in stride angle may influence the energy cost of running and lead to improved performance.