Can an inertial measurement unit (IMU) in combination with machine learning measure fast bowling speed and perceived intensity in cricket?

This study examined whether an inertial measurement unit (IMU), in combination with machine learning, could accurately predict two indirect measures of bowling intensity through ball release speed (BRS) and perceived intensity zone (PIZ). One IMU was attached to the thoracic back of 44 fast bowlers. Each participant bowled 36 deliveries at two different PIZ zones (Zone 1 = 24 deliveries at 70% to 85% of maximum perceived bowling effort; Zone 2 = 12 deliveries at 100% of maximum perceived bowling effort) in a random order. IMU data (sampling rate = 250 Hz) were downsampled to 125 Hz, 50 Hz, and 25 Hz to determine if model accuracy was affected by the sampling frequency. Data were analysed using four machine learning models. A two-way repeated-measures ANOVA was used to compare the mean absolute error (MAE) and accuracy scores (separately) across the four models and four sampling frequencies. Gradient boosting models were shown to be the most consistent at measuring BRS (MAE = 3.61 km/h) and PIZ (F-score = 88%) across all sampling frequencies. This method could be used to measure BRS and PIZ which may contribute to a better understanding of overall bowling load which may help to reduce injuries.

Cycling related major trauma in Ireland

INTRODUCTION

Cycling as a means of transport or recreational activity is increasing in popularity in Ireland. However, increasing numbers of cyclists may lead to an increased number of bicycle collisions and fatalities. The Road Safety Authority is the statutory body for road safety in Ireland but uses police data alone to collate cycling collision statistics. This may lead to an underestimation of cycling injuries in Ireland. Using hospital statistics may provide a greater understanding of cycling trauma in Ireland.

OBJECTIVE

The present study examines cycling related trauma in Ireland using the Major Trauma Audit (MTA) data collected via the Trauma and Research Network (TARN) from hospitals in Ireland for the period 2014 to 2016. The database was interrogated for demographics, mechanism of injury, injury characteristics and patient outcomes.

RESULTS

There were 410 cycling collisions recorded in the TARN database which represented 4.4% of trauma captured by TARN for the study period. Of this cohort 79% were male compared with 58% in the overall (TARN) trauma cohort (p < 0.001) and the median (IQR) age was 43.8 years (31.0, 55.7) which is younger than the median (IQR) of 58.9 (36.2, 76.0) years for the overall trauma cohort (p < 0.001). Cycling collisions had a median (IQR) injury severity score (ISS) of 10 (9, 20) which was higher than the overall trauma cohort ISS of 9 (9, 17). Of the mechanisms observed for cycling trauma, 31.7% (n = 130) had a collision with a motor vehicle. Of those who did not wear a helmet, 52.2% (n = 47) sustained a head injury compared with 27.5% (n = 44) in the group who were wearing a helmet (p < 0.001).

CONCLUSION

The TARN data presented in this paper builds a more complete overview of the burden of cycling collisions in Ireland. Particular points of focus are that serious cycling injuries occur in a predominantly male population, and that only around 30% of cases are recorded as involving a motor vehicle, with the majority having an unknown mechanism of injury. There was an association between helmets and head injuries in this study, but there are likely other contributing factors such as mechanism of injury, velocity or cycling infrastructure. Using hospital data such as the MTA provides valuable information on the injuries sustained by cyclists, but more prospective studies to capture injury mechanism and contributing factors are needed.

Effects of Warming Up With Lower-Body Wearable Resistance on Physical Performance Measures in Soccer Players Over an 8-Week Training Cycle

Bustos, A, Metral, G, Cronin, J, Uthoff, A, and Dolcetti, J. Effects of warming up with lower-body wearable resistance on physical performance measures in soccer players over an 8-week training cycle. J Strength Cond Res 34(5): 1220-1226, 2020-Warm-ups provide an opportune time to integrate specific movements to improve performance. This study aimed to examine the effects of adding wearable resistance (WR) lower-limb loading to a warm-up on physical performance measures in soccer athletes. Thirty-one national-level soccer players (aged 16-18 years) were matched for speed and allocated to either a WR training (WRT = 15) or an unloaded (CON = 16) group. Both groups performed the same warm-up 2-3x·wk for 8 weeks with the WRT group wearing 200- to 600-g loads on their calves. Pre-training, mid-training, and post-training data were collected for 10- and 20-m sprint times, repeated sprint ability, and vertical countermovement jump (CMJ) and horizontal countermovement jump (standing long jump [SLJ]) performance. Wearable resistance training improved pre-training to post-training 10- and 20-m sprint times more than the unloaded training (effect size [ES] = -1.06 to -0.96, respectively; 60.0-66.7 vs. 18.8-37.5% > smallest worthwhile change [SWC]). Both groups decreased CMJ over the first 4 weeks (ES ≥ 0.45) and increased CMJ performance over the second 4 weeks of training (ES ≥ 0.27). Both the WRT and CON groups improved SLJ performance after the 8-week training block (ES = 0.85 and 0.93, respectively; 86.7 and 62.5% > SWC, respectively), yet no differences were identified between groups. These findings indicate that 8 weeks (23 sessions) of WR training appears to elicit practically meaningful improvements in accelerated sprinting and horizontal jumping performance. Strength and conditioning practitioners should consider including WR in sports where sprinting and horizontal force production are critical performance indicators.

Using geographic information systems to map older people's emergency department attendance for future health planning

Objectives

This study aimed to assess the pattern of use of EDs, factors contributing to the visits, geographical distribution and outcomes in people aged 65 years or older to a large hospital in Dublin.

Methods

A retrospective analysis of 2 years of data from an urban university teaching hospital ED in the southern part of Dublin was reviewed for the period 2014–2015 (n=103 022) to capture the records of attenders. All ED presentations by individuals 65 years and older were extracted for analysis. Address-matched records were analysed using QGIS, a geographic information systems (GIS) analysis and visualisation tool to determine straight-line distances travelled to the ED by age.

Results

Of the 49 538 non-duplicate presentations in the main database, 49.9% of the total are women and 49.1% are men. A subset comprised of 40 801 had address-matched records. When mapped, the data showed a distinct clustering of addresses around the hospital site but this clustering shows different patterns based on age cohort. Average distances travelled to ED are shorter for people 65 and older compared with younger patients. Average distances travelled for those aged 65–74 was 21 km (n=4177 presentations); for the age group 75–84, 18 km (n=2518 presentations) and 13 km for those aged 85 and older (n=2104 presentations). This is validated by statistical tests on the clustered data. Self-referral rates of about 60% were recorded for each age group, although this varied slightly, not significantly, with age.

Conclusions

Health planning at a regional level should account for the significant number of older patients attending EDs. The use of GIS for health planning in particular can assist hospitals to improve their understanding of the origin of the cohort of older ED patients.

Quantification of the validity and reliability of sprint performance metrics computed using inertial sensors: A systematic review

BACKGROUND

Wearable inertial sensors enable sprinting to be biomechanically evaluated in a simple and time efficient manner outside of a laboratory setting.

RESEARCH QUESTION

Are wearable inertial sensors a valid and reliable method for collecting and measuring sprint performance variables compared to referenced systems?

METHODS

PubMed, SPORTDiscus, and Web of Science were searched using the Boolean phrases: ((run* OR sprinting OR sprint*) AND (IMU OR inertial sensor OR wearable sensor OR accelerometer OR gyroscope) AND (valid* OR reliabil*)). Articles with injury-free subjects of any age, sex or activity level were included.

RESULTS

Fifteen studies met the inclusion criteria and were retained for analysis. In summary, higher Intra-class correlation [ICC] or Pearson correlation coefficients (r) were observed for contact time (ICC ≥ 0.80, r ≥ 0.99), trunk angular displacement (r ≥ 0.99), vertical and horizontal force (ICC ≥ 0.88), and theoretical measures of force, velocity and power (r ≥ 0.81). Low coefficient of variation (CV) were found in peak velocity (≤ 1%), average velocity (≤ 3%), and contact time (≤ 3%,). Average and peak velocity, and resultant forces, were found to have a wide range of r (0.32-0.92) and CVs (0.78-20.2%). The lowest r (-0.24 to 0.49) and highest CVs (15-22.4%) were noted for average acceleration, crania-caudal force, instantaneous forces, medio-lateral ground reaction forces, and rate of decrease in ratio of forces.

SIGNIFICANCE

Due to a wide range of methodological differences, a clear understanding of the validity and reliability of different inertial sensors for the analysis of sprinting has yet to be established. Future research into the sensor's placement, attachment method and sampling frequency are among several factors that need further investigation.

Cricket fast bowling detection in a training setting using an inertial measurement unit and machine learning

Fast bowlers are at a high risk of overuse injuries. There are specific bowling frequency ranges known to have negative or protective effects on fast bowlers. Inertial measurement units (IMUs) can classify movements in sports, however, some commercial products can be too expensive for the amateur athlete. As a large number of the world's population has access to an IMU (e.g. smartphones), a system that works on a range of different IMUs may increase the accessibility of automated workload monitoring in sport. Seventeen elite fast bowlers in a training setting were used to train and/or validate five machine learning models by bowling and performing fielding drills. The accuracy of machine learning models trained using data from all three bowling phases (pre-delivery, delivery and post-delivery) were compared to those trained using only the delivery phase at a sampling rate of 250 Hz. Next, models were trained using data down-sampled to 125 Hz, 50 Hz, and 25 Hz to mimic results from lower specification sensors. Models trained using only the delivery phase showed similar accuracy (> 95%) to those trained using all three bowling phases. When delivery-phase data were down-sampled, the accuracy was maintained across all models and sampling frequencies (>96%).

A New Direction to Athletic Performance: Understanding the Acute and Longitudinal Responses to Backward Running

Backward running (BR) is a form of locomotion that occurs in short bursts during many overground field and court sports. It has also traditionally been used in clinical settings as a method to rehabilitate lower body injuries. Comparisons between BR and forward running (FR) have led to the discovery that both may be generated by the same neural circuitry. Comparisons of the acute responses to FR reveal that BR is characterised by a smaller ratio of braking to propulsive forces, increased step frequency, decreased step length, increased muscle activity and reliance on isometric and concentric muscle actions. These biomechanical differences have been critical in informing recent scientific explorations which have discovered that BR can be used as a method for reducing injury and improving a variety of physical attributes deemed advantageous to sports performance. This includes improved lower body strength and power, decreased injury prevalence and improvements in change of direction performance following BR training. The current findings from research help improve our understanding of BR biomechanics and provide evidence which supports BR as a useful method to improve athlete performance. However, further acute and longitudinal research is needed to better understand the utility of BR in athletic performance programs.

Effect of Match Factors on the Running Performance of Elite Female Soccer Players

Trewin, J, Meylan, C, Varley, MC, Cronin, J, and Ling, D. Effect of match factors on the running performance of elite female soccer players. J Strength Cond Res 32(7): 2002-2009, 2018-The purpose of this study was to examine the effects of match factors on the match running of elite female soccer players. Players from the same women's national team (n = 45) were monitored during 47 international fixtures (files = 606) across 4 years (2012-2015) using 10-Hz global positioning system devices. A mixed model was used to analyze the effects of altitude, temperature, match outcome, opposition ranking, and congested schedules. At altitude (>500 m), a small increase in the number of accelerations (effect size [ES] = 0.40) and a small decrease in total distance (ES = -0.54) were observed, whereas at higher temperatures, there were decreases in all metrics (ES = -0.83 to -0.16). Playing a lower ranked team in a draw resulted in a moderate increase in high-speed running (ES = 0.89), with small to moderate decreases in total distance and low-speed running noted in a loss or a win. Winning against higher ranked opponents indicated moderately higher total distance and low-speed running (ES = 0.75), compared with a draw. Although the number of accelerations were higher in a draw against lower ranked opponents, compared with a win and a loss (ES = 0.95 and 0.89, respectively). Practitioners should consider the effect of match factors on match running in elite female soccer.

Rating of Perceived Exertion as a Method of Volume Autoregulation Within a Periodized Program

Helms, ER, Cross, MR, Brown, SR, Storey, A, Cronin, J, and Zourdos, MC. Rating of perceived exertion as a method of volume autoregulation within a periodized program. J Strength Cond Res 32(6): 1627-1636, 2018-The purpose of this investigation was to observe how a rating of perceived exertion (RPE)-based autoregulation strategy impacted volume performed by powerlifters. Twelve (26 ± 7 years, n = 9 men, n = 3 women) nationally qualified powerlifters performed the back squat, bench press, and deadlift 3x per week on nonconsecutive days in a session order of hypertrophy, power, and then strength; for 3 weeks. Each session subjects performed an initial top set for a prescribed number of repetitions at a target RPE. A second top set was performed if the RPE score was too low, then subsequent back-off sets at a reduced load were performed for the same number of repetitions. When the prescribed RPE was reached or exceeded, sets stopped; known as an "RPE stop." The percentage load reduction for back-off sets changed weekly: there were 2, 4, or 6% RPE stop reductions from the top set. The order in which RPE stop weeks were performed was counterbalanced among subjects. Weekly combined relative volume load (squat + bench press + deadlift), expressed as sets x repetitions x percentage 1-repetition maximum was different between weeks (p < 0.001): 2% = 74.6 ± 22.3; 4% = 88.4 ± 23.8; 6% = 114.4 ± 33.4. Combined weekly bench press volume (hypertrophy + power + strength) was significantly higher in accordance with load reduction magnitude (2% > 4% > 6%; p ≤ 0.05), combined squat volume was greater in 6 vs. 2% (p ≤ 0.05), and combined deadlift volume was greater in 6 vs. 2% and 4% (p ≤ 0.05). Therefore, it does seem that volume can be effectively autoregulated using RPE stops as a method to dictate number of sets performed.

Prescribing Target Running Intensities for High-School Athletes: Can Forward and Backward Running Performance Be Autoregulated?

Target running intensities are prescribed to enhance sprint-running performance and progress injured athletes back into competition, yet is unknown whether running speed can be achieved using autoregulation. This study investigated the consistency of running intensities in adolescent athletes using autoregulation to self-select velocity. Thirty-four boys performed 20 m forward running (FR) and backward running (BR) trials at slow, moderate and fast intensities (40⁻55%, 60⁻75% and +90% maximum effort, respectively) on three occasions. Absolute and relative consistency was assessed using the coefficient of variation (CV) and intraclass correlation coefficients (ICC). Systematic changes in 10 and 20 m performance were identified between trials 1⁻2 for moderate and fast BR (p ≤ 0.01) and during moderate BR over 20 m across trials 2⁻3 (p ≤ 0.05). However, comparisons between trials 2⁻3 resulted in low typical percentage error (CV ≤ 4.3%) and very good to excellent relative consistency (ICC ≥ 0.87) for all running speeds and directions. Despite FR being significantly (p ≤ 0.01) faster than BR at slow (26%), moderate (28%) and fast intensities (26%), consistency was similar in both running directions and strongest at the fastest speeds. Following appropriate familiarization, youth athletes may use autoregulation to self-select prescribed FR and BR target running intensities.

Sprint running kinematics and kinetics in pre-peak-height-velocity male children on a non-motorised treadmill: reliability and normative data

The purpose of this study was to quantify the reliability of kinematic and kinetic variables using a sample of pre-peak-height-velocity (PHV) male athletes sprinting on a non-motorised treadmill. Following variables were measured and their normative data presented, average and peak velocity, average and peak power, average and peak horizontal force, average and peak vertical force, average step frequency, average step length, average work. Twenty-five participants performed three 5-s all-out sprints from a standing split start on a non-motorised treadmill on three separate occasions. Per cent change in the means (-3.66 to 3.35%) and coefficients of variation (0.56-7.81%) were thought reliable for all variables. However, average step rate, average horizontal force and average vertical force did not meet the standards (≥0.70) set for acceptable intraclass correlation coefficients (ICC). Due to the homogeneous group, it was expected to receive low ICC values. Therefore, youth sprinting performance can be tested reliably on a non-motorised treadmill, especially if the per cent change in the mean and CV are deemed the important reliability measures. Normative data are given for the participant's age as well as their maturity level for kinematic and kinetic variables.

A Brief Review of Handgrip Strength and Sport Performance

Cronin, J, Lawton, T, Harris, N, Kilding, A, and McMaster, DT. A brief review of handgrip strength and sport performance. J Strength Cond Res 31(11): 3187-3217, 2017-Tests of handgrip strength (HGS) and handgrip force (HGF) are commonly used across a number of sporting populations. Measures of HGS and HGF have also been used by practitioners and researchers to evaluate links with sports performance. This article first evaluates the validity and reliability of various handgrip dynamometers (HGD) and HGF sensors, providing recommendations for procedures to ensure that precise and reliable data are collected as part of an athlete's testing battery. Second, the differences in HGS between elite and subelite athletes and the relationships between HGS, HGF, and sports performance are discussed.

Self-Rated Accuracy of Rating of Perceived Exertion-Based Load Prescription in Powerlifters

This study assessed male (n = 9) and female (n = 3) powerlifters' (18-49 years) ability to select loads using the repetitions in reserve-based rating of perceived exertion (RPE) scale for a single set for squat, bench press, and deadlift. Subjects trained 3× per week. For 3 weeks on nonconsecutive days in the weekly order of hypertrophy (8 repetitions at 8 RPE), power (2 repetitions at 8 RPE), and strength (3 repetitions at 9 RPE), using subject-selected loads intended to match the target RPE. Bench press and squat were performed every session and deadlift during strength and power only. Mean absolute RPE differences (|reported RPE-target RPE|) ranged from 0.22-0.44, with a mean of 0.33 ± 0.28 RPE. There were no significant RPE differences within lifts between sessions for squat or deadlift. However, bench press was closer to the target RPE for strength (0.15 ± 0.42 RPE) vs. power (-0.21 ± 0.35 RPE, p = 0.05). There were no significant differences within session between lifts for power and strength. However, bench press was closer (0.14 ± 0.44 RPE) to the target RPE than squat (-0.19 ± 0.21 RPE) during hypertrophy (p = 0.02). Squat power was closer to the target RPE in week 3 (0.08 ± 0.29 RPE) vs. 1 (-0.46 ± 0.69 RPE, p = 0.03). It seems that powerlifters can accurately select loads to reach a prescribed RPE. However, accuracy for 8-repetition sets at 8 RPE may be better for bench press compared with squat. Rating squat power-type training may take 3 weeks to reach peak accuracy. Finally, bench press RPE accuracy seems better closer rather than further from failure (i.e., 3-repetition 9 RPE sets vs. 2-repetition 8 RPE sets).

Overnight Emergency CT Imaging: A 10-Year Experience at an Irish Tertiary Referral Hospital

In recent years there has been increased utilisation of computed tomography (CT) imaging in developed countries, however there is a paucity of data regarding the utilisation of CT in the emergency overnight setting. We retrospectively analysed trends in 'overnight' (midnight to 8am) CT utilisation over a ten-year period at a single Irish tertiary referral hospital. Over the study period, we observed a significant increase in the proportion of CT imaging that was carried out overnight. There was no significant variation in the yield of pathological findings over the study period, which remained low (64% of CT studies were normal or had non-critical findings). The multiple factors which have contributed to the increased utilization of overnight emergency CT in recent years, the potential for reporting errors overnight and the implications therein for patient safety warrant consideration.

Use of emergency department point-of-care ultrasound in a case of cholecystitis

A 54-year-old man presented with severe right upper quadrant (RUQ) abdominal pain. He denied any infective symptoms. On clinical examination, he was afebrile and anicteric. His abdomen was soft with tenderness elicited on the RUQ. A point-of-care ultrasound in the emergency department demonstrated a distended gallbladder with a thickened wall and an impacted large gallstone at the neck of the gallbladder. Furthermore, the point-of-care ultrasound also identified a highly reflective echo from the anterior surface of the gallstone and marked posterior acoustic shadowing. A diagnosis of cholecysitis was made after confirmatory ultrasonography performed in the radiology department. The patient had a cholecystostomy performed under interventional radiology and was managed with course of intravenous antibiotics for 7 days. He was discharged from hospital with an elective cholecystectomy planned to be performed 8 weeks posthospital discharge.