Karl Gibbon

Low impact weight-bearing exercise in an upright posture achieves greater lumbopelvic stability than overground walking

The aim of this study was to determine the kinematic differences between movements on a new exercise device (EX) that promotes a stable trunk over a moving, unstable base of support, and overground walking (OW). Sixteen male participants performed EX and OW trials while their movements were tracked using a 3D motion capture system. Trunk and pelvis range of motion (ROM) were similar between EX and OW in the sagittal and frontal planes, and reduced for EX in the transverse plane. The pelvis was tilted anteriorly, on average, by about 16° in EX compared to OW. Hip and knee ROM were reduced in EX compared to OW. The exercise device appears to promote similar or reduced lumbopelvic motion, compared to walking, which could contribute to more tonic activity of the local lumbopelvic musculature.

Enhanced Corticospinal Excitability and Volitional Drive in Response to Shortening and Lengthening Strength Training and Changes Following Detraining

There is a limited understanding of the neurological adaptations responsible for changes in strength following shortening and lengthening resistance training and subsequent detraining. The aim of the study was to investigate differences in corticospinal and spinal responses to resistance training of the tibialis anterior muscle between shortening or lengthening muscle contractions for 4 weeks and after 2 weeks of detraining. Thirty-one untrained individuals were assigned to either shortening or lengthening isokinetic resistance training (4 weeks, 3 days/weeks) or a non-training control group. Transcranial magnetic stimulation and peripheral nerve stimulation (PNS) were used to assess corticospinal and spinal changes, respectively, at pre-, mid-, post-resistance training and post detraining. Greater increases changes (P < 0.01) in MVC were found from the respective muscle contraction training. Motor evoked potentials (expressed relative to background EMG) significantly increased in lengthening resistance training group under contraction intensities ranging from 25 to 80% of the shortening and lengthening contraction intensity (P < 0.01). In the shortening resistance training group increases were only seen at 50 and 80% of both contraction type. Volitional drive (V-wave) showed a greater increase following lengthening resistance training (57%) during maximal lengthening contractions compared to maximal shortening contractions following shortening resistance training (23%; P < 0.001). During the detraining period MVC and V-wave did not change (P > 0.05), although MEP amplitude decreased during the detraining period (P < 0.01). No changes in H-reflex were found pre to post resistance training or post detraining. Modulation in V-wave appeared to be contraction specific, whereby greatest increases occurred following lengthening resistance training. Strength and volitional drive is maintained following 2 weeks detraining, however corticospinal excitability appears to decrease when the training stimulus is withdrawn.

Investigating the Effects of Typical Rowing Strength Training Practices on Strength and Power Development and 2,000 m Rowing Performance

Abstract This study aimed to determine the effects of a short-term, strength training intervention, typically undertaken by club-standard rowers, on 2,000 m rowing performance and strength and power development. Twenty-eight male rowers were randomly assigned to intervention or control groups. All participants performed baseline testing involving assessments of muscle soreness, creatine kinase activity (CK), maximal voluntary contraction (leg-extensors) (MVC), static-squat jumps (SSJ), counter-movement jumps (CMJ), maximal rowing power strokes (PS) and a 2,000 m rowing ergometer time-trial (2,000 m) with accompanying respiratory-exchange and electromyography (EMG) analysis. Intervention group participants subsequently performed three identical strength training (ST) sessions, in the space of five days, repeating all assessments 24 h following the final ST. The control group completed the same testing procedure but with no ST. Following ST, the intervention group experienced significant elevations in soreness and CK activity, and decrements in MVC, SSJ, CMJ and PS (p < 0.01). However, 2,000 m rowing performance, pacing strategy and gas exchange were unchanged across trials in either condition. Following ST, significant increases occurred for EMG (p < 0.05), and there were non-significant trends for decreased blood lactate and anaerobic energy liberation (p = 0.063 – 0.086). In summary, club-standard rowers, following an intensive period of strength training, maintained their 2,000 m rowing performance despite suffering symptoms of muscle damage and disruption to muscle function. This disruption likely reflected the presence of acute residual fatigue, potentially in type II muscle fibres as strength and power development were affected.

Reliability and Precision of Sonography of the Lumbar Multifidus and Transversus Abdominis During Dynamic Activities: Reliability of Sonography in Dynamic Activities

To determine the intrarater reliability and precision of lumbar multifidus and transversus abdominis thickness measurements using freehand sonography in a range of static and dynamic conditions.

Response to: Reproducibility of 24-h ambulatory blood pressure and measures of autonomic function

The aim of our study was to assess the reproducibility of 24-h ambulatory blood pressure, 24-h heart rate variability (HRV) and short-term resting measurements of both HRV and blood pressure variability. We reported the magnitude of between-day variability in these measures and the appropriateness of familiarisation sessions before experimental data collection. Findings revealed that ambulatory blood pressure became more reproducible following repeated recordings. In addition, 24-h HRV was more reproducible than resting measures. Consecutive pairs of measurements (days 1–2, 2–3, 3–4) were analysed for the determination of the typical error and coefficient of variation as described by Hopkins [2]. These statistical methods provide a point estimate of absolute and relative reliability and reflect the ability of a measure to detect systematic changes between repeated measurements within a participant [3]. These methods also quantify the degree of uncertainty surrounding this point estimate and can be used by researchers to evaluate the likelihood that observed changes following an intervention in a sample population are attributable to the experimental conditions and not a manifestation of error inherent within the test. The effect of a therapeutic intervention on autonomic function and blood pressure is a fertile area of contemporary research [4], and the data presented in our manuscript are appropriate to inform practitioners making population-wide health recommendations based on the outcomes of experimental research.