Detection of Ground Contact Times with Inertial Sensors in Elite 100-m Sprints under Competitive Field Conditions

Abstract

This study describes a method for extracting the stride parameter ground contact time (GCT) from inertial sensor signals in sprinting. Five elite athletes were equipped with inertial measurement units (IMU) on their ankles and performed 34 maximum 50 and 100-m sprints. The GCT of each step was estimated based on features of the recorded IMU signals. Additionally, a photo-electric measurement system covered a 50-m corridor of the track to generate ground truth data. This corridor was placed interchangeably at the first and the last 50-ms of the track. In total, 863 of 889 steps (97.08%) were detected correctly. On average, ground truth data were underestimated by 3.55 ms. The root mean square error of GCT was 7.97 ms. Error analyses showed that GCT at the beginning and the end of the sprint was classified with smaller errors. For single runs the visualization of step-by-step GCT was demonstrated as a new diagnostic instrument for sprint running. The results show the high potential of IMUs to provide the temporal parameter GCT for elite-level athletes.

Wearables for Running Gait Analysis: A Systematic Review

“…Across these studies, the most common sampling frequency was 100 Hz ( n = 12) [ 19 , 21 , 28 , 29 , 38 , 42 , 73 , 75 , 76 , 78 , 82 , 94 ], but included use of 10 Hz [ 36 ] and 2000 Hz [ 43 ], and the range of the accelerometers was between ± 2.0 g [ 36 ] and ± 200 g [ 56 , 57 ], with 16 g being the most frequently used ( n = 14) [ 24 , 26 , 36 , 59 , 83 , 85 – 89 , 99 , 100 , 102 , 103 ]. The gyroscope ranges (± °/s) used were 1200 ( n = 7) [ 19 , 20 , 59 , 86 – 89 ], 2000 ( n = 10) [ 21 , 26 , 42 , 61 , 83 , 85 , 92 , 100 , 102 , 103 ], 4000 [ 43 ] and a variety ( n = 1) [ 36 ]. A variety of sampling frequencies (4–1000 Hz), accelerometer (2, 4, 6, 8, 16 g) and gyroscope ranges (250, 500, 1000, 2000°/s) were used in one study that used an IMU [ 36 ].…”

“…Sixty-two articles stated that they used IMUs; however, 14 of these studies only used the accelerometer capabilities within the IMU [23,24,38,52,56,57,62,[72][73][74][75][76][77][78] and 20 studies stated they used the accelerometer and gyroscope components for the data analysis [26,33,43,49,50,54,59,61,[79][80][81][82][83][84][85][86][87][88][89][90]. The remaining 27 studies either did not comment on components used [70,[91][92][93][94][95][96][97][98] or implied they used all accelerometer, gyroscope and magnetometer components for the data analysis [19-21, 28, 29, 36, 42, 99-109].…”

“…Across these studies, the most common sampling frequency was 100 Hz (n = 12) [19,21,28,29,38,42,73,75,76,78,82,94], but included use of 10 Hz [36] and 2000 Hz [43], and the range of the accelerometers was between ± 2.0 g [36] and ± 200 g [56,57], with 16 g being the most frequently used (n = 14) [24, 26, 36, 59, 83, 85-89, 99, 100, 102, 103]. The gyroscope ranges (± °/s) used were 1200 (n = 7) [19,20,59,[86][87][88][89], 2000 (n = 10) [21,26,42,61,83,85,92,100,102,103], 4000 [43] and a variety (n = 1) [36] Fig. 1 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 flow diagram.…”

“…Thirty-one studies used controlled speeds, with the slowest speed set at 7 km/h [84] and the fastest speed set at 26 km/h [117]. Self-selected speeds were used in 21 studies, with a range from jogging [136] to maximum effort/sprint [86,99,100,102,104,105,129,133]. An additional five studies combined controlled and self-selected speeds [62,76,116,127,135].…”

“…) assessed shoe-mounted or foot-mounted devices. Reviewed studies showed that wearables could accurately measure stride time [85], speed, oscillation and GCT measures [79,86,134], step rate [93], FSP data [26,81,84,116] and SL [100] using shoe or foot mounted wearable technology. Conflicting findings regarding the validity of joint kinematics using shoe-mounted accelerometers were demonstrated [73,83,94].…”