The Effect of Step Frequency and Running Speed on the Coordination of the Pelvis and Thigh Segments During Running.

This study investigates the specific influence of step frequency (SF) and speed on the coordination between pelvic and thigh movements. Eight recreational male runners ran at different SFs and speeds on an instrumented treadmill. The coordination between the pelvis and thigh segments was analyzed using modified vector coding in the sagittal and frontal planes (FPs).

Submaximal force-velocity relationships during mountain ultramarathon: Data from the field.

This study presents a novel method for evaluating the submaximal velocity-force (V(F)) relationship in mountain ultramarathon races using crowdsourced data from Strava.com. The dataset includes positional data from 408 participants of the 171-km UTMB® 2023 race (9,850-m D+).

Test-Retest Reliability and Usefulness of a Foot-Ankle Rebound-Jump Test for Measuring Foot-Ankle Reactive Strength in Athletes.

Purpose: This study investigated the test-retest reliability and usefulness of the foot-ankle rebound-jump test (FARJT) for measuring foot-ankle reactive strength metrics in athletes.

Methods: Thirty-six highly trained, healthy athletes (5 female; 21.5 [3.

Reliability and measurement error of a maximal voluntary toe plantarflexion measurement process.

Despite the growing interest, information regarding the psychometric properties of maximal voluntary isometric toe plantarflexion force and rate of force development (RFD) is lacking. Hence, we investigate the test-retest reliability and measurement error of these outcome measurement instruments measured with a custom-built dynamometer. Twenty-six healthy adults participated in a crossed design with four sessions separated by 5-7 days.

The potential impact of advanced footwear technology on the recent evolution of elite sprint performances.

Background: Elite track and field sprint performances have reached a point of stability as we near the limits of human physiology, and further significant improvements may require technological intervention. Following the widely reported performance benefits of new advanced footwear technology (AFT) in road-running events, similar innovations have since been applied to sprint spikes in hope of providing similar performance enhancing benefits. However, it is not yet clear based on current evidence whether there have been subsequent improvements in sprint performance.

Concurrent Validity and Reliability of the Sprint Force-Velocity Profile Assessed with K-AI Wearable Tech.

Establishing a sprint acceleration force-velocity profile is a way to assess an athlete's sprint-specific strength and speed production capacities. It can be determined in field condition using GNSS-based (global navigation satellite system) devices. The aims of this study were to (1) assess the inter-unit and the inter-trial reliability of the force-velocity profile variables obtained with K-AI Wearable Tech devices (50 Hz), (2) assess the concurrent validity of the input variables (maximal sprint speed and acceleration time constant), and (3) assess the validity of the output variables (maximal force output, running velocity and power).

Exploring the Role of Sprint Biomechanics in Hamstring Strain Injuries: A Current Opinion on Existing Concepts and Evidence.

Hamstring strain injuries are one of the most common injuries in sprint-based sports with the mechanism of injury considered the result of an interaction between applied mechanical strain and the capacity of the muscle to tolerate strain. To date, injury prevention and rehabilitation strategies have frequently focused on enhancing the capacity of the hamstrings to tolerate strain, with little consideration of factors directly influencing mechanical strain. Sprint running biomechanics are one factor proposed to influence the mechanical strain applied to the hamstrings that may be modified (towards reduced strain) within rehabilitation and injury prevention programs.

Mechanical and metabolic power in accelerated running-Part II: team sports.

Purpose: This manuscript is devoted to discuss the interplay between velocity and acceleration in setting metabolic and mechanical power in team sports.

Methods: To this aim, an essential step is to assess the individual Acceleration-Speed Profile (ASP) by appropriately analysing training sessions or matches. This allows one to estimate maximal mechanical and metabolic power, including that for running at constant speed, and hence to determine individual thresholds thereof.

Exploring the Low Force-High Velocity Domain of the Force-Velocity Relationship in Acyclic Lower-Limb Extensions.

Purpose: To compare linear and curvilinear models describing the force-velocity relationship obtained in lower-limb acyclic extensions, considering experimental data on an unprecedented range of velocity conditions.

Methods: Nine athletes performed lower-limb extensions on a leg-press ergometer, designed to provide a very broad range of force and velocity conditions. Previously inaccessible low inertial and resistive conditions were achieved by performing extensions horizontally and with assistance.

Mechanical and Metabolic Power in Accelerated Running-PART I: the 100-m dash.

Purpose: Acceleration phases require additional mechanical and metabolic power, over and above that for running at constant velocity. The present study is devoted to a paradigmatic example: the 100-m dash, in which case the forward acceleration is very high initially and decreases progressively to become negligible during the central and final phases.

Methods: The mechanical ([Formula: see text]) and metabolic ([Formula: see text]) power were analysed for both Bolt's extant world record and for medium level sprinters.

Opposition Skill Efficiency During Professional Rugby Union Official Games Is Related to Horizontal Force-Production Capacities in Sprinting.

Purpose: This study aimed to determine relationships between parameters of force-production capacity in sprinting and opposition skill efficiency in rugby union games according to position.

Methods: The sprint force-velocity profile of 33 professional rugby union players divided into 2 subgroups (forwards and backs) was measured on a 30-m sprint. Skill efficiencies (in percentage) of offensive duels, tackles, and rucks were assessed using objective criteria during 12 consecutive competitive games.

Sprint Acceleration Mechanical Outputs Derived from Position- or Velocity-Time Data: A Multi-System Comparison Study.

To directly compare five commonly used on-field systems (motorized linear encoder, laser, radar, global positioning system, and timing gates) during sprint acceleration to (i) measure velocity−time data, (ii) compute the main associated force−velocity variables, and (iii) assess their respective inter-trial reliability. Eighteen participants performed three 40 m sprints, during which five systems were used to simultaneously and separately record the body center of the mass horizontal position or velocity over time. Horizontal force−velocity mechanical outputs for the two best trials were computed following an inverse dynamic model and based on an exponential fitting of the position- or velocity-time data.

Effects of Fatigue Induced by Repeated Sprints on Sprint Biomechanics in Football Players: Should We Look at the Group or the Individual?

The aim of this study was to analyse the influence of fatigue on sprint biomechanics. Fifty-one football players performed twelve maximal 30 m sprints with 20 s recovery between each sprint. Sprint kinetics were computed from running speed data and a high-frequency camera (240 Hz) was used to study kinematic data.

Concurrent Validity and Reliability of Sprinting Force-Velocity Profile Assessed With GPS Devices in Elite Athletes.

Purpose: The aims of this study were to (1) assess the concurrent validity of global positioning systems (GPSs) against a radar device to measure sprinting force-velocity (F-v) profiles and (2) evaluate the interunit reliability of 10-Hz GPS devices (Vector S7, Catapult Innovations).

Methods: Sixteen male elite U18 rugby union players (178.3 [7.