The purpose of the study was to evaluate kinematics of the lower extremity during the stance phase of an endurance training run. Fifteen participants (8 male, 7 female; 30.5 ±8.4 years; 71.8 ±11 kg; 1.73 ±0.07 m) reported that they were currently signed up for, or planned on signing up for, an endurance race within the next six months of participation in the study (9 half marathon, 3 marathon, 1 triathlon, 2 21k trail run). All had a weekly running mileage greater than 20 miles (23.8 ±4.6 miles). Participants were required to complete the 15-kilometer training run in less than 2 hours (1:24:34 ± 0:10:20 finish times). Participants signed an institutionally approved informed consent form upon arrival and then completed the PAR-Q. Participants were instructed to complete the 15- km run as if it were a normal training run, lacking any competitive nature. Sagittal plane kinematic data were captured and processed via MaxTraq two-dimensional (2-D) video acquisition software (Innovisions Systems Inc. 2.2.2.5; Columbiaville, MI) at 120 Hz. All stance phase variables were smoothed using a Low-Pass 4th Order Butterworth Zero-lag filter. Data analysis included descriptive statistics for all dependent variables (lap times, stance phase (StPh), step length (SL), step frequency (SF), speed, torso inclination at foot contact (TorsoFC), and all lower extremity angles at foot contact and peak flexion of each joint during stance (AnkFC, AnkPK, KneeFC, KneePK, HipFC, and HipPK). Oneway repeated measure ANOVAs were conducted for each dependent variable (α=0.05). Results identified significant within subject differences for gait parameters in lap times (F[2.790,39.065] = 15.829, p<0.001, η² = 0.531), StPh (F[2.427,33.983] = 8.877, p<0.001, η² = 0.388), SL (F[1.223, 17.119] = 6.025, p=0.020, η² = 0.301) and speed (F[1.299, 18.191] = 6.131, p=0.017, η² = 0.305). Pairwise comparisons showed Lap_1 was significantly faster than Lap_2 (6.20s p=0.002), Lap_3 (9.81s, p<0.001), Lap_4 (12.98s, p<0.001) and Lap_5 (10.39s, p = 0.013), while Lap_2 was significantly faster than Lap_3 (3.61s, p=0.010) and Lap_4 (6.78s, p=0.012) for lap times. Pairwise comparisons showed StPh for Lap_1 was significantly shorter than Lap_2 (0.01s p=0.011), Lap_3 (0.01s, p=0.030) and Lap_4 (0.02s, p=0.007). The knee joint showed the only significant difference for joint position at foot contact (F[4,56] = 2.674, p = 0.041, η² = 0.160) and peak flexion during stance (F[4,56] = 3.304, p = 0.017, η² = 0.191). Runners in the current study were able to maintain their lower extremity joint kinematics at foot contact and during the stance phase even while there were measured differences in lap times, speed and step lengths. The knee joint appeared to be the most highly affected lower extremity joint by speed and time during an endurance run.