Assessing infant carriage systems: ground reaction force implications for gait of the caregiver

Objective: To assess the acute alterations of anterior infant carriage systems on the ground reaction force experienced during over ground walking. Background: Previous research has identified the alterations in posture and gait associated with an increased anterior load (external or internal); however the forces applied to the system due to the altered posture during over ground walking have not been established. Method: Thirteen mixed gender participants completed forty-five over ground walking trials at a self-selected pace under three loaded conditions (unloaded, semi-structured carrier 9.9kg and structured carrier 9.9kg). Each trial consisted of a fifteen metre walkway, centred around a piezoelectric force platform sampling at 1200 Hz. Differences were assessed between loaded and unloaded conditions and across carriers using paired samples t-tests and repeated measures ANOVA. Results: Additional load increased all ground reaction force parameters; however, the magnitude of force changes was influenced by carrier structure. The structured carrier displayed increased force magnitudes, a reduction in the time to vertical maximum heel contact and an increased duration of the flat foot phase in walking gait. Conclusion: Evidence suggest that the acute application of anterior infant carriers alters both kinetic and temporal measures of walking gait. Importantly these changes appear to be governed not solely by the additional mass but also by the structure of the carrier. Application: These findings indicate carrier structure should be considered by the wearer and may be used to inform policy in the recommendation of anterior infant carriage systems use by caregivers

Postural stability is affected in older males with Haemophilia—a matched control study

Despite fall-related injuries having serious consequences for older haemophilic patients, few studies have investigated their postural stability and risk of falls. The aim was to examine postural stability, joint function and joint mobility in haemophiliacs and age-matched controls. Centre of pressure excursions in four 60 s balance conditions, two minute walk test, passive ankle and knee range of motion, Haemophilia Joint Health Score, and Haemophilia Early Arthropathy Detection with Ultrasound score were measured in eight men with haemophilia (people with heamophilia, PWH), and eight age-matched men without haemophilia (people without heamophilia, PWOH). PWH have significantly worse postural stability under physically perturbed conditions (p = 0.001–0.028, η2p = 0.19–0.34), reduced joint function (p = 0.001–0.010, d = 1.33–2.62) and mobility (p < 0.001–0.025, d = 1.01–4.61), and increased centre of pressure (CoP) velocity (p < 0.001–0.003) when compared to PWOH. Postural stability among PWH did not deteriorate with time standing, although significant decreases compared to PWOH across all time intervals were observed (Eyes Open Foam (EOF) CoP ellipse (time x group) p = 0.011, η2p = 0.28; path (time × group) p = 0.035, η2p = 0.21; EOF CoP antero-posterior (AP) (time × group) p = 0.021, η2p = 0.24). Joint function, mobility, and postural stability are reduced in PWH compared to PWOH, driven by differences in the CoP AP range. Dynamic tests incorporating physical perturbation may be more effective than static balance tests on a level surface, and longer period of time to assess postural stability may determine whether fatigue affects ability of PWH to maintain postural stability. Adoption of a possible ‘hip strategy’ by which to achieve balance suggests falls prevention programs need to focus on increasing hip strength and retraining ankle strategy movement to allow PWH to improve balance stability

"Hero Imagery" - Are there performance advantages associated with imagining yourself as your favourite athlete?

Objectives: This study examined whether there are performance advantages associated with a single bout of imagery when imagining yourself ‘as your favourite athlete’, or imagining yourself performing a strength-based task. Design: A blind 2 (Imagery ability: high, low) x 3 (imagery condition: self, “hero”, control) mixed factorial design was used. Methods: Participants (n = 17 male; Mage = 19.7 ± 2.7) completed the Sport Imagery Ability Questionnaire then viewed a standardised video demonstrating the grip strength (GS) task. Three baseline trials separated by one minute were then executed. Three imagery scripts (control, self, hero) were then presented to participants via an MP3 player in a counterbalanced order (an interval of 1-minute was provided between each condition). The conclusion of each imagery script prompted participants to perform the GS task. Performance in each condition was conceptualised as delta change scores (Imagery condition – baseline average). Results: No main effects were present but there was a group x condition interaction (F(2,28) = 4.27, p = .02. ƞ_p^2= .23. The interaction suggests that for individuals with high imagery ability, simply “doing the imagery that they already do” is preferable compared to a scripted self- or hero-imagery condition. For individuals with a low imagery ability, a simple script whether that is self- or hero- based may enhance strength performance, compared to “what they already do”. Conclusion: Imagery ability may influence the effectiveness of a brief imagery intervention. Further examination of processes and outcomes associated with “hero-imagery” is recommended