Efficacy of neuromuscular exercises to promote movement quality and reduce musculoskeletal injury during initial military training in Royal Navy recruits.

INTRODUCTION: Musculoskeletal injuries (MSKIs) are a significant problem in the Royal Navy, contributing to 48% of all medical discharges from service between 2019 and 2020. The objective of the study was to assess efficacy of implementing a neuromuscular training intervention to improve movement quality and reduce MSKIs in Royal Navy recruits undertaking initial military training. METHODS: Neuromuscular training (pre-activation exercises, focusing on hip control) was integrated into the warm-up exercise regimen preceding physical training during the 10-week initial naval training (recruits) programme (January-March 2020) at HMS Raleigh (intervention group; n=162). A control group comprised (n=90) of recruits entering training from January 2019, who completed the standard warm-up programme prior to physical training. Movement control of the intervention group (intervention) was assessed before and after the 10-week programme using the Hip and Lower-Limb Movement Screen (HLLMS). Injury incidence proportion for both groups was determined retrospectively by review of medical notes. RESULTS: The control group's MSKI incidence proportion was 31%, which was higher (p<0.05) than the 8% reported in the intervention group. The majority of MSKIs were of the lower limb, and were reported in weeks 1, 2 and 5 of the 10-week training programme. Movement control, as assessed by the HLLMS score, improved (pretraining (week 1) and post-training (week 10) HLLMS score (mean (SD) pre: 11.2 (5.6); post: 8.4 (3.9); t=5.829, p<0.001) following the neuromuscular training in the intervention group but was not assessed in the control group. CONCLUSION: A neuromuscular control intervention was successfully implemented during the initial military training in the Royal Navy. The cohort undertaking the intervention demonstrated lower injury incidence compared with an equivalent cohort of recruits who undertook standard training. Movement control improved following the intervention, indicating better movement quality. Continued use of the programme may reduce military training attrition in the Royal Navy.

Measuring scapular kinematics during arm lowering using the acromion marker cluster.

The aim of the present study was to examine the acromion marker cluster (AMC) method of measuring scapular kinematics during the arm lowering, eccentric, phase. Twenty six participants completed arm elevation and lowering in the sagittal, frontal and scapular plane. The participants held their arm at 30° increments while the orientation of the scapula was recorded using an AMC and a scapular locator (SL). There were no significant differences between the AMC and SL during the lowering phase for sagittal and scapular plane arm movements. The AMC significantly underestimated upward rotation (max RMSE = 6.0°), and significantly overestimated posterior tilt (max RMSE = 7.2°) during arm lowering in the frontal plane. The reported root mean square errors, however, were within the ranges observed during the elevation phase and reported in previous literature. The AMC therefore provides a reasonable description of scapular kinematics during the arm lowering phase.

Reliability of kinematic parameters during unilateral upper limb reaching tasks using a portable motion tracking system.

The reliability of a portable computer based system (Motor Task Manager; MTM) used for the assessment of motor dysfunction needs to be assessed before being used clinically. Nine healthy males, aged 24-55 years (mean = 31.4, SD +/- 9.84) performed three unilateral MTM-prescribed reaching task paradigms. Tasks were completed three times in random order during three separate testing sessions. Speed characteristics showed excellent (Intra-class correlation coefficient; ICC 0.78-0.92) and inter-session (ICC 0.86-0.92) reliability for all three tasks. Temporal parameters had fair to good reliability in the first session (ICC 0.42-0.78) which improved in sessions 2 and 3 (ICC 0.64-0.96). Inter-session reliability for temporal characteristics was better for movement time (ICC 0.57-0.84) than onset time (ICC 0.14-0.53). Spatial characteristics demonstrated poor intra- (ICC -0.09-0.63) and inter-sessions (ICC 0.15-0.61) reliability. Speed characteristics were the most robust results for the healthy population studied and recommended for measuring performance, particularly if only one test session is possible.

Comparison of curvilinear and linear ultrasound imaging probes for measuring cross-sectional area and linear dimensions.

The aim of the study was to determine whether different ultrasound probe/transducer configurations produce the same measurements. Two investigators undertook 10 scans of a general purpose semi-solid multi-tissue ultrasound phantom (phantom A) using two ultrasound scanners with a linear and curvilinear probe. From those 10 scans, two measurements of cross-sectional area (CSA), width and thickness were made. These measurements were then repeated with an open-top fluid-filled phantom, with 10% ethanol solution (phantom B). Intra- and inter-rater reliability were examined using Bland and Altman plots. Agreement between measurements made with the two probe types was also assessed using Bland and Altman plots. An independent samples t-test was used to compare statistical differences between probe type configuration. There was a significant difference (p < 0.05) and a tendency for increased measurements in CSA and width, and decreased measurements in thickness when using a curvilinear probe on phantom A, and these differences were not scanner specific. When imaging phantom B there were no significant differences in measurements between probe configurations; however there was a small bias for smaller CSA measurements with a curvilinear probe. In conclusion there are small differences in measurements obtained from different ultrasound probe configurations using a semi-solid phantom, but their clinical significance is unknown.

Effect of prostaglandin F(2)alpha at insemination on sperm cell numbers and pregnancy rate in beef cattle.

Fourteen cycling, nonlactating, multiparous beef cows were artificially inseminated (AI) 10 to 12 h after the onset of natural estrus. One unit of frozen-thawed semen containing 100 x 10(6) total sperm cells was deposited into the body of the uterus. Immediately after AI, alternating cows were injected i.m. with either 25 mg (5 ml) of prostaglandin F(2)alpha (PGF) or 5 ml of 0.9% saline-benzyl alcohol control solution. Cows were slaughtered 16 +/- 1 h post AI, oviducts were retrieved, segmented into thirds (upper, middle and lower) and flushed with 1 ml of 0.2% gluteraldehyde in phosphate buffered saline. The number of sperm cells was counted using a phase contrast microscope. There were no right or left side effects (P=0.61) on the number of sperm cells recovered per oviduct within cow (389 vs 553; average SEM = 219). PGF had no effect (P=0.77) on the number of sperm cells recovered per oviduct (642 vs 300; average SEM = 231 for PGF and control females, respectively). More sperm cells were recovered from the lower third segment (P<0.05) compared with the middle and upper segments. Ovulation tended to affect (P=0.10) the number of sperm cells recovered per oviduct (742 vs 200; average SEM = 231). Additionally, 114 beef females (68 Angus x Hereford heifers and 46 Chianina crossbred postpartum suckled cows) were treated as described above following AI at natural estrus with 20 x 10(6) motile sperm cells. Pregnancy rates did not differ significantly in heifers (70.6 vs 58.8%) or in Chianina cows (34.8 vs 52.2%) for control and PGF-treated females, respectively. Overall, pregnancy rates were identical between control and PGF-treated females at 56.1%. In this study, PGF treatment immediately following AI in beef cattle had no effect on the number of sperm cells in the oviducts or on the pregnancy rate.