Assessment of Sprint Parameters in Top Speed Interval in 100 m Sprint—A Pilot Study Under Field Conditions

Abstract

Improving performances in sprinting requires feedback on sprint parameters such as step length and step time. However, these parameters from the top speed interval (TSI) are difficult to collect in a competition setting. Recent advances in tracking technology allows to provide positional data with high spatio-temporal resolution. This pilot study, therefore, aims to automatically obtain general sprint parameters, parameters characterizing, and derived from TSI from raw speed. In addition, we propose a method for obtaining the intra-cyclic speed amplitude in TSI. We analyzed 32 100 m-sprints of 7 male and 9 female athletes (18.9 ± 2.8 years; 100 m PB 10.55–12.41 s, respectively, 12.18–13.31 s). Spatio-temporal data was collected with a radio-based position detection system (RedFIR, Fraunhofer Institute, Germany). A general velocity curve was fitted to the overall speed curve (vbase), TSI (upper quintile of vbase values) was determined and a cosine term was added to vbase within TSI (vcycle) to capture the cyclic nature of speed. This allowed to derive TSI parameters including TSI amplitude from the fitted parameters of the cosine term. Results showed good approximation for vbase (error: 5.0 ± 1.0%) and for vcycle (2.0 ± 1.0%). For validation we compared spatio-temporal TSI parameters to criterion values from laser measurement (speed) and optoelectric systems (step time and step length) showing acceptable RMSEs for mean speed (0.08 m/s), for step time (0.004 s), and for step length (0.03 m). Top speed interval amplitude showed a significant difference between males (mean: 1.41 m/s) and females (mean: 0.71 m/s) and correlations showed its independence from other sprint parameters. Gender comparisons for validation revealed the expected differences. This pilot study investigated the feasibility of estimating sprint parameters from high-quality tracking data. The proposed method is independent of the data source and allows to automatically obtain general sprint parameters and TSI parameters, including TSI amplitude assessed here for the first time in a competition-like setting.

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

“…Especially for validation purposes, the study design should focus on an appropriate criterion measurement system. The criterion measurement system in the current study, Optogait, is a commonly accepted method for ground truth data acquisition [7,13]. The recent study's setup-including the alternation of the 50-m corridor-was also used in other studies [7].…”

“…The criterion measurement system in the current study, Optogait, is a commonly accepted method for ground truth data acquisition [7,13]. The recent study's setup-including the alternation of the 50-m corridor-was also used in other studies [7]. Additionally, the time-synchronization of all systems could improve the insights during the algorithm development.…”

“…For ground truth data acquisition, a 50 m corridor of photoelectric bars on the ground (Optogait, Bolzano, Microgate, Bolzano, Italy) was used. Optogait was used already as criterion measurement system in previous sprinting studies [7,13,30]. This system is modularly composed of 1 m bars, which can be connected to cover an arbitrary distance.…”

“…In sprinting, a negative correlation between GCT and performance in a sample including french elite-level sprinters was found [5]. Especially GCT is an essential parameter in sprinting [6] but is not commonly available in training and competition settings until now [7].…”

“…This also implies that GPS is not suitable for this detection. For reliable sprint parameter detection, photoelectric systems like Optogait or Optojump are commonly used [7,[12][13][14]. However, before the measurement, these systems need to be set up on the running track carefully, thus requiring a large effort and not suited for analyses of official competitions.…”