Effects of motor skill level and speed on movement variability during running

Running-Related Injury Incidence: Does It Correlate with Kinematic Sub-groups of Runners? A Scoping Review

BACKGROUND

Historically, kinematic measures have been compared across injured and non-injured groups of runners, failing to take into account variability in kinematic patterns that exist independent of injury, and resulting in false positives. Research led by gait patterns and not pre-defined injury status is called for, to better understand running-related injury (RRI) aetiology and within- and between-group variability.

OBJECTIVES

Synthesise evidence for the existence of distinct kinematic sub-groups across a population of injured and healthy runners and assess between-group variability in kinematics, demographics and injury incidence.

DATA SOURCES

Electronic database search: PubMed, Web of Science, Cochrane Central Register of Controlled Trials (Wiley), Embase, OVID, Scopus.

ELIGIBILITY CRITERIA

Original, peer-reviewed, research articles, published from database start to August 2022 and limited to English language were searched for quantitative and mixed-methods full-text studies that clustered injured runners according to kinematic variables.

RESULTS

Five studies (n = 690) were included in the review. All studies detected the presence of distinct kinematic sub-groups of runners through cluster analysis. Sub-groups were defined by multiple differences in hip, knee and foot kinematics. Sex, step rate and running speed also varied significantly between groups. Random injury dispersal across sub-groups suggests no strong evidence for an association between kinematic sub-groups and injury type or location.

CONCLUSION

Sub-groups containing homogeneous gait patterns exist across healthy and injured populations of runners. It is likely that a single injury may be represented by multiple movement patterns, and therefore kinematics may not predict injury risk. Research to better understand the underlying causes of kinematic variability, and their associations with RRI, is warranted.

Effects of running skill and speed on limb coordination during submaximal and maximal sprinting

In locomotion, the relative phasing of the limbs changes with speed and provides valuable insight to neuromuscular control of gait. At present, it is unknown if individuals trained in sprinting coordinate their limbs differently than runners from other athletic backgrounds. Therefore, we aimed to characterize the effects of speed and skill on lower limb coordination. Twenty-five physically active (PA) and fifteen track and field (TF) athletes performed 40 m running trials at self-selected speeds, from jogging to maximal sprinting. We measured lower limb kinematics during steady-speed running, and quantified coordination using continuous relative phase (CRP) methods for interlimb pairs (Thigh-Thigh, Shank-Shank) and intralimb pairs (Shank-Thigh). Regression techniques showed between-group differences in scaling of coordination with speed during the stance phase, such that coordination was significantly more antiphase during jogging and running speeds in TF. During flight the scaling between groups was similar, but there were persistent and significant differences in coordination across all speeds. Comparing only the maximal speed trials, we found interlimb coordination was significantly more antiphase for TF in both stance and flight. In all cases, Shank-Shank coordination showed the largest between-group differences. Our results demonstrate the importance of interlimb coordination at maximal sprint speed, particularly during the flight phase and between shank segments. Between-group differences in coordination at slower speeds suggest a selective tuning of coordination in trained runners. We speculate differences in limb coordination are due to acquired motor patterns from optimizing forward velocity and its mechanical determinants, which differ particularly during flight/swing and between shank segments.

Pre-pubertal runners demonstrate greater variability in running kinematics than post-pubertal runners

BACKGROUND

Adolescents undergo a period of motor incoordination during puberty characterized by high movement variability. It is unknown if differences in running kinematics variability exist among adolescent long-distance runners.

RESEARCH QUESTION

Is kinematic variability different among male and female adolescent long-distance runners of different stages of physical maturation?

METHODS

We enrolled 114 adolescent long-distance runners (ages 8-19, F = 55, M = 59) in this secondary analysis of a larger cross-sectional study. Participants completed a three-dimensional overground running analysis at a comfortable self-selected speed. Peak frontal, sagittal, and transverse plane hip, knee, and ankle/shoe joint angles from the right leg were identified during stance phase for at least five trials. Variability in running kinematics was quantified as the standard deviation of the peak joint angles among the running trials for each participant. Participants were stratified by sex and stage of physical maturation (pre-, mid-, post-pubertal) and two-way ANOVAs compared between-subjects variability among groups (p ≤ .05).

RESULTS

Significant sex by maturation interactions were observed for hip external rotation and ankle external rotation variability. Sex differences were observed for hip internal rotation, with males demonstrating greater variability, and ankle internal rotation, with females demonstrating greater variability. Pre-pubertal runners demonstrated significantly greater variability than mid-pubertal runners for hip flexion, and greater variability than post-pubertal runners for hip flexion, hip adduction, hip internal rotation, and knee flexion.

SIGNIFICANCE

Pre-pubertal adolescent long-distance runners demonstrate greater stance phase variability in running kinematics than post-pubertal adolescent long-distance runners, while adolescent males and females demonstrate similar variability. Anthropometric and neuromuscular changes that occur during puberty likely influence running patterns and may contribute to more consistent kinematic patterns for post-pubertal runners.

Stride length mediates the correlation between movement coordination and sprint velocity

In this study, we aimed to explore the correlation between movement coordination and sprint velocity and the mediating effects of stride length and frequency on this correlation. Thirty-two male college students (16 athletes and 16 non-athletes) participated in this study. Movement coordination was calculated using a vector coding method for intralimb (hip - knee, knee - ankle) and interlimb (hip - hip, knee - knee, ankle - ankle). There was a significant effect of group on hip - knee, hip - hip and ankle - ankle coupling angle during braking phase and knee - knee coupling angle during the propulsive phase. In all participants, the hip - hip coupling angle during the braking phase was positively correlated with sprint velocity, and the ankle - ankle coupling angle during the braking phase was negatively correlated with sprint velocity. Stride length mediated the relationship between hip - hip coupling angle and sprint velocity. In conclusion, the anti-phase of the hip - hip coupling angle and the swing phase of the ankle - ankle coupling angle may contribute to sprint velocity. Moreover, the correlation between hip - hip coupling angle and sprint velocity was related to stride length rather than stride frequency.

A Proposed Framework to Describe Movement Variability within Sporting Tasks: A Scoping Review

Movement variability is defined as the normal variations in motor performance across multiple repetitions of a task. However, the term "movement variability" can mean different things depending on context, and when used by itself does not capture the specifics of what has been investigated. Within sport, complex movements are performed repeatedly under a variety of different constraints (e.g. different situations, presence of defenders, time pressure). Movement variability has implications for sport performance and injury risk management. Given the importance of movement variability, it is important to understand the terms used to measure and describe it. This broad term of "movement variability" does not specify the different types of movement variability that are currently being assessed in the sporting literature. We conducted a scoping review (1) to assess the current terms and definitions used to describe movement variability within sporting tasks and (2) to utilise the results of the review for a proposed framework that distinguishes and defines the different types of movement variability within sporting tasks. To be considered eligible, sources must have assessed a sporting movement or skill and had at least one quantifiable measure of movement variability. A total of 43 peer-reviewed journal article sources were included in the scoping review. A total of 280 terms relating to movement variability terminology were extracted using a data-charting form jointly developed by two reviewers. One source out of 43 (2%) supplied definitions for all types of movement variability discussed. Moreover, 169 of 280 terms (60%) were undefined in the source material. Our proposed theoretical framework explains three types of movement variability: strategic, execution, and outcome. Strategic variability describes the different approaches or methods of movement used to complete a task. Execution variability describes the intentional and unintentional adjustments of the body between repetitions within the same strategy. Outcome variability describes the differences in the result or product of a movement. These types emerged from broader frameworks in motor control and were adapted to fit the movement variability needs in sports literature. By providing specific terms with explicit definitions, our proposed framework can ensure like-to-like comparisons of previous terms used in the literature. The practical goal of this framework is to aid athletes, coaches, and support staff to gain a better understanding of how the different types of movement variability within sporting tasks contribute to performance. The framework may allow training methods to be tailored to optimise the specific aspects of movement variability that contribute to success. This review was retrospectively registered using the Open Science Framework (OSF) Registries ( https://osf.io/q73fd ).

An Analysis of Lower Limb Coordination Variability in Unilateral Tasks in Healthy Adults: A Possible Prognostic Tool

Interlimb coordination variability analysis can shed light into the dynamics of higher order coordination and motor control. However, it is not clear how the interlimb coordination of people with no known injuries change in similar activities with increasing difficulty. This study aimed to ascertain if the interlimb coordination variability range and patterns of healthy participants change in different unilateral functional tasks with increasing complexity and whether leg dominance affects the interlimb coordination variability. In this cross-sectional study fourteen younger participants with no known injuries completed three repeated unilateral sit-to-stands (UniSTS), step-ups (SUs), and continuous-hops (Hops). Using four inertial sensors mounted on the lower legs and thighs, angular rotation of thighs and shanks were recorded. Using Hilbert transform, the phase angle of each segment and then the continuous relative phase (CRP) of the two segments were measured. The CRP is indicative of the interlimb coordination. Finally, the linear and the nonlinear shank-thigh coordination variability of each participant in each task was calculated. The results show that the linear shank-thigh coordination variability was significantly smaller in the SUs compared to both UniSTS and Hops in both legs. There were no significant differences found between the latter two tests in their linear coordination variability. However, Hops were found to have significantly larger nonlinear shank-thigh coordination variability compared to the SUs and the UniSTS. This can be due to larger vertical and horizontal forces required for the task and can reveal inadequate motor control during the movement. The combination of nonlinear and linear interlimb coordination variability can provide more insight into human movement as they measure different aspects of coordination variability. It was also seen that leg dominance does not affect the lower limb coordination variability in participants with no known injuries. The results should be tested in participants recovering from lower limb injuries.