Tim Doyle

• Doctor of Philosophy
• Professor (Associate) at Macquarie University

This study investigated the feasibility of a field-based gait retraining program using real-time axial peak tibial acceleration (PTA) feedback in high-impact recreational runners and explored the effects on running biomechanics and economy. We recruited eight recreational runners with high landing impacts to undertake eight field-based sessions wit...

Measuring lower extremity impact acceleration is a common strategy to identify runners with increased injury risk. However, existing axial peak tibial acceleration (PTA) thresholds for determining high‐impact runners typically rely on small samples or fixed running speeds. This study aimed to describe the distribution of axial PTA among runners at...

Background/Objectives: Aviation firefighting is a strenuous occupation that requires individuals to engage in intense physical activity amidst elevated stress levels and extreme environmental conditions. Despite this, there has been limited investigation regarding the internal and external loads associated with aviation firefighting tasks, which in...

Integrating running gait coordination assessment into athlete monitoring systems could provide unique insight into training tolerance and fatigue-related gait alterations. This study investigated the impact of an overload training intervention and recovery on running gait coordination assessed by field-based self-testing. Fifteen trained distance r...

Introduction Overuse musculoskeletal injuries (MSKIs) remain a significant medical challenge in military personnel undergoing military training courses; a further understanding of the biological process leading to overuse MSKI development and biological signatures for injury risk are warranted. The purpose of this study was to determine the associa...

Step‐up variations are frequently used in sports performance to develop coordinated and powerful movements that transfer to running. This study aimed to quantify the kinetic characteristics of the first foot contact of four different step‐up variations. Ten professional rugby league players participated in this study and performed the Barbell One B...

The ability to estimate lower-extremity mechanics in real-world scenarios may untether biomechanics research from a laboratory environment. This is particularly important for military populations where outdoor ruck marches over variable terrain and the addition of external load are cited as leading causes of musculoskeletal injury As such, this stu...

This study investigated the relationships between inertial measurement unit (IMU) acceleration at multiple body locations and 3D motion capture impact landing measures in runners. Thirty healthy runners ran on an instrumented treadmill at five running speeds (9–17 km/h) during 3D motion capture. Axial and resultant acceleration were collected from...

Purpose: There are important methodological considerations for translating wearable-based gait-monitoring data to field settings. This study investigated different devices' sampling rates, signal lengths, and testing frequencies for athlete monitoring using dynamical systems variables. Methods: Secondary analysis of previous wearables data (N =...

Objectives: Determine the influence of clinically-measured maximum dorsiflexion, dynamic peak dorsiflexion and percent of clinically-measured maximum dorsiflexion used during a drop-jump task on landing biomechanics and risk of ankle injury in military personnel. Design: Prospective cohort study. Methods: 672 participants (122 women) enrolled....

Purpose: Firefighters are required to complete arduous occupational tasks in hazardous environments. To enhance occupational readiness and reduce injury risk, firefighters should perform regular exercise. However, exercise injuries are commonly incurred by firefighters. Therefore, it is important to identify injury mechanisms among firefighters to...

Purpose: Firefighter injuries are commonly incurred during exercise training. However, there is a lack of research evaluating risk factors of exercise injuries. Therefore, the purpose of this investigation was to describe firefighters’ perceptions of intrapersonal, interpersonal, and institutional factors associated with exercise injuries. Methods:...

Management strategies for patellofemoral pain often involve modifying running distance or speed. However, the optimal modification strategy to manage patellofemoral joint (PFJ) force and stress accumulated during running warrants further investigation. This study investigated the effect of running speed on peak and cumulative PFJ force and stress i...

Introduction: Decision making in use of force relies on accurate cue identification to inform appropriate response. This research was designed to test the relationship between cue utilisation and performance prior to, and following participation in an urban operations course (UOC). Methods: A total of 37 participants were assessed on cue utilisa...

Markerless motion capture has improved physical screening efficiency in sport and occupational settings; however, reliability of kinematic measurements from commercial systems must be established. Further, the impact of torso-borne equipment on these measurements is unclear. The purpose of this study was to evaluate the reliability of HumanTrak, a...

This study aimed to validate a 7-sensor inertial measurement unit system against optical motion capture to estimate bilateral lower-limb kinematics. Hip, knee, and ankle sagittal plane peak angles and range of motion (ROM) were compared during bodyweight squats and countermovement jumps in 18 participants. In the bodyweight squats, left peak hip fl...

Recently, commercial grade technologies have provided black box algorithms potentially relating to musculoskeletal injury (MSKI) risk and functional movement deficits, in which may add value to a high-performance model. Thus, the purpose of this manuscript was to evaluate composite and component scores from commercial grade technologies association...

Background Investigators have proposed that various physical head and neck characteristics, such as neck strength and head and neck size, are associated with protection from mild traumatic brain injury (mTBI/concussion). Objectives To systematically review the literature and investigate potential relationships between physical head and neck charac...

This study aimed to determine the influence of running speed on patellofemoral joint (PFJ) kinetics. Twenty recreational runners ran on an instrumented treadmill at four running speeds with simultaneous 3D motion capture. A musculoskeletal model derived peak and cumulative (per 1km of continuous running) PFJ force and stress for each speed. Peak PF...

The purpose of this study was to assess the reliability of a markerless motion capture system, the VALD HumanTrak, for estimating shoulder range of motion. Intra-and inter-day and fixed-and free-range reliability was assessed for shoulder sagittal and frontal plane movements. Results were calculated for three sessions, with 16 general population pa...

This study tested transferability and validity of an Inertial Measurement Unit (IMU) system for estimation of lower limb kinematics. Peak hip, knee, and plantarflexion angles and sagittal plane range of motion (ROM) were compared during body weight squats (BWSQ) and countermovement jumps (CMJ) in 16 participants using root mean square error (RMSE)...

The diverse and grueling nature of activities undertaken during Special Forces selection makes it difficult to develop physical training to improve performance and reduce injury risk. It is generally accepted that increased strength is protective against injury, but it is unclear if this is evident in a Special Forces selection environment. This st...

The HumanTrak captures human movement through markerless motion tracking and can be a crucial tool in military physical screening. Reliability was examined in eighteen healthy participants who completed shoulder and hip ROM, and dynamic tasks in three body armour conditions. Generally, for all conditions, good to excellent reliability was observed...

The purpose of this study was to investigate the behaviour of physiological load measures as well as ground reaction forces (GRF) and acceleration load during a prolonged running task that simulated the running demands of an intermittent team sport. Nineteen males completed a maximal aerobic fitness test and an extended running protocol across two...

Musculoskeletal injuries (MSKI) are a significant burden on the military healthcare system. Movement strategies, genetics, and fitness level have been identified as potential contributors to MSKI risk. Screening measures associated with MSKI risk are emerging, including novel technologies, such as markerless motion capture (mMoCap) and force plates...

Objective The purpose of this meta-analytic review is to examine the relationship between increased psychological pressure and Use of Force (UOF) behaviours, identifying current training methodologies and effectiveness of transfer of training interventions in high threat-simulated scenarios. Background Data from UOF performance within Law Enforcem...

Objective: To evaluate the effectiveness of running gait retraining on kinematics, kinetics, performance, pain, and injury in distance runners. Design: Intervention systematic review with meta-analysis. Literature search: Seven electronic databases from inception to March 2021. Study selection criteria: Randomised controlled trials that (i)...

Introduction The purpose of this study was to identify and characterize sex-specific physical and psychophysical performance adaptations in response to a novel 10-week training program. Materials and Methods Fifteen males and thirteen females completed a standardized load carriage task (5 km at 5.5 km.h−1, wearing a 23 kg torso-borne vest) before...

The effects of running gait retraining on biomechanics, performance, pain and injury: a systematic review and meta-analysis Introduction: It is common for runners to consider or be instructed to modify their running gait based on theoretical links between running biomechanics and performance or injury. This review aimed to synthesise evidence from...

Conkright, WR, Beckner, ME, Sinnott, AM, Eagle, SR, Martin, BJ, Lagoy, AD, Proessl, F, Lovalekar, M, Doyle, TLA, Agostinelli, P, Sekel, NM, Flanagan, SD, Germain, A, Connaboy, C, and Nindl, BC. Neuromuscular performance and hormonal responses to military operational stress in men and women. J Strength Cond Res XX(X): 000-000, 2021-Women have recent...

Introduction The purpose of this study was to investigate sex-specific lower limb biomechanical adaptations during a standardized load carriage task in response to a targeted physical training program. Materials and Methods Twenty-five healthy civilians (males [n = 13] and females [n = 12]) completed a load carriage task (5 km at 5.5 km·h−1, weari...

Glassbrook, DJ, Fuller, JT, Wade, JA, and Doyle, TLA. Not all physical performance tests are related to early season match running performance in professional rugby league. J Strength Cond Res 36(7): 1944-1950, 2022-This study aimed to determine which physical tests correlate with early season running performance. Sixteen professional rugby league...

Background Quantifying lower-limb load and asymmetry during team sport match-play may be important for injury prevention and understanding performance. However, current analysis methods of lower-limb symmetry during match-play employ wearable microtechnology that may not be best suited to the task. A popular microtechnology is global positioning sy...

Wade, JA, Fuller, JT, Devlin, PJ, and Doyle, TLA. Senior and junior rugby league players improve lower-body strength and power differently during a rugby league season. J Strength Cond Res 36(5): 1367-1372, 2022-This investigation evaluated lower-body strength and power changes across a rugby league season in elite junior and senior athletes. Twent...

Purpose: To characterize and evaluate female-specific physiological and perceptual responses during a load carriage walking task before and after a 10-week physical training program. Methods: Eleven recreationally active females (age; 21.5 ± 2.2 years, stature; 1.66 ± 0.8 m, body mass; 64.4 ± 6.8 kg) completed a load carriage task (5 km at 5.5 k...

This investigation determined differences in lower body strength and power between elite junior (17-20 years) and elite senior (open-aged) rugby league athletes. Twenty junior and 25 senior athletes performed an isometric mid-thigh pull, countermovement jump, repeated jump, and broad jump tests during a National Rugby League pre-season. The effects...

Accelerometers are often placed on the tibia to measure segmental accelerations, and external mechanical load during running. However, in applied sport settings it is sometimes preferable to place accelerometers on the dorsal foot to avoid tibial impact injuries. This study aimed to quantify the differences in accelerations measured at the dorsal f...

Soldiers routinely conduct load carriage and physical training to meet occupational requirements. These tasks are physically arduous and are believed to be the primary cause of musculoskeletal injury. Physical training can help mitigate injury risk when specifically designed to address injury mechanisms and meet task demands. This study aimed to as...

Carrying body-borne load causes large hip joint forces that may explain why soldiers sustain high rates of overuse hip injuries

Objective: Fatigue due to game play is often cited as a factor in musculoskeletal injuries; however, it is unclear whether or not this view is supported by published research findings. Given the importance researchers and practitioners place on the potential effects of game play with respect to injury, it is important to understand what inferences...

Wills, JA, Saxby, DJ, Glassbrook, DJ, and Doyle, TLA. Load-carriage conditioning elicits task-specific physical and psychophysical improvements in males. J Strength Cond Res XX(X): 000-000, 2019-Load carriage is a requirement of many military roles and is commonly used as an assessment of soldier physical readiness. Loaded, compared with unloaded,...

Background: Rugby league is a collision sport, where players are expected to be physically competent in a range of areas, including aerobic fitness, strength, speed and power. Several studies have attempted to characterise the physical demands of rugby league match-play, but these studies often have relatively small sample sizes based on one or tw...

A 10-week resistance training program decreases perceived task demands of a loaded walk and could be utilised by Military organisations to elicit positive training responses to improve load-carriage capacity.

Musculoskeletal injuries (MSI) in the military reduce soldier capability and impose substantial costs. Characterizing biomechanical surrogates of MSI during commonly performed military tasks (e.g., load carriage) is necessary for evaluating the effectiveness of possible interventions to reduce MSI risk. This study determined the effects of body-bor...

Root mean square error (RMSE) and coefficient of determination (R2) for CEINMS-derived torques and inverse dynamics-derived torques during stance phase. (DOCX)

Stance phase medial compartment tibiofemoral contact force for the no load, 15 kg, and 30 kg load magnitudes. (CSV)

Peak medial and lateral compartment, and total tibiofemoral contact forces for walking speed and load magnitude used for statistical comparisons, including the no load condition. (CSV)

Stance phase total tibiofemoral contact force for the no load, 15 kg, and 30 kg load magnitudes. (CSV)

Peak medial and lateral compartment, and total tibiofemoral contact forces for each armour type and walking speed configuration used for statistical comparisons. (CSV)

Descriptions and illustrations of different types of body armor and load configurations. (DOCX)

Muscle contributions to medial and lateral tibiofemoral contact forces across the different carried loads and walking speeds. (DOCX)

Stance phase lateral compartment tibiofemoral contact force for the no load, 15 kg, and 30 kg load magnitudes. (CSV)

Soldiers regularly transport loads weighing >20 kg at slow speeds for long durations. These tasks elicit high energetic costs through increased positive work generated by knee and ankle muscles, which may increase risk of muscular fatigue and decrease combat readiness. This study aimed to determine how modifying where load is borne changes lower-li...

There are several methods for calculating inter-limb symmetry, an inter-limb difference ≥15% has been suggested as an indicator of sporting injury risk. The purpose of this study was to compare three common methods for determining symmetry: the Symmetry Index (percentage difference; SI) when referenced to the left limb (SILeft) or the average of bo...

The purpose of this study was to identify and characterise physical performance responses to a targeted 10-week load-carriage physical training intervention in males. Performance measures of maximal strength, heart rate, rating of perceived exertion, and basic fitness from nine male civilians before and after the 10-week training intervention are p...

PURPOSE Musculoskeletal injuries (MSI) in the military reduce soldier capability and impose substantial costs [1]. Most interventions to reduce MSI have so far proven ineffective, possibly because they do not target the mechanical factors causing injury. Research focus should shift to characterising biomechanical surrogates of MSI during physically...

Objectives To determine the effects of different body armour types, carried loads, and walking speeds on trunk and lower-limb joint biomechanics. Design Within-subjects repeated measures to determine the effects of different body armour types, carried loads, and walking speeds on trunk and lower-limb joint biomechanics. Methods Twenty soldiers (2...

Soldiers carry heavy loads that may cause general discomfort, shoulder pain, and injury. This study assessed if new body armour designs that incorporated a hip belt reduced shoulder pressures and improved comfort. Twenty-one Australian soldiers completed treadmill walking trials wearing six different body armours with two different loads (15 kg and...

Soldier attrition due to musculoskeletal injuries (MSI) has increased globally within the last 10 years, causing reduced workforce capability and substantial costs. Exposure to the physical demands of military service, including heavy load carriage, is associated with MSI risk. Predictors of MSI include biomechanical parameters that describe mechan...

Objectives To investigate how knee kinematics, kinetics and loading changes during sidestepping tasks following a prolonged running protocol performed in a laboratory setting. Design All participants performed sidestepping, and crossover cutting tasks in a randomised order before and after a 60 minute running protocol on a non-motorised treadmill...

Body armor covers anatomical landmarks that would otherwise be used to track trunk and pelvis movement in motion analysis. This study developed and evaluated a new marker set, and compared it to placing markers on the skin and over-top of body armor. In our method, pelvis and trunk motions were measured using a custom-built sacral and upper-back ma...

The equipment carried by soldiers offers them protection, communication, and supplies for sustained activity. While operationally essential, carried load may contribute to the large musculoskeletal overuse injury burden in the armed forces. In addition to the significant outpatient costs for rehabilitation, military organisations pay to re-train ne...

Background Exercise-based training programs are a popular injury prevention measure to prevent sports injuries but there have been few trials of their effectiveness in real-world sports settings. Methods A clustered randomised controlled trial was undertaken in 18 community-level (non-elite) Australian Football (AF) clubs in two states with multip...

Soldiers undergo regular physical testing to assess their functional capacity. However, current physical tests, such as push-ups, sit-ups, and pull-ups, do not necessarily assess job-specific physical capability. This article assesses the utility of generic predictive tests and a task-related predictive test in predicting performance against four j...

To quantify joint motion, researchers position physical markers over anatomical landmarks on the skin surface. However, body armour occludes landmarks on the pelvis and torso. In load carriage research, the markers are often placed over body armour, or the marker set is simplified. In these instances the physical markers may misrepresent actual mot...

Carrying a casualty on a stretcher is a critical task conducted in a range of occupations. To ensure that personnel have the requisite physical capacity to conduct this task, two bilateral jerry can carries were used to predict individual performance in a four-person stretcher carry. Results demonstrated a bilateral 22-kg jerry can carry (R² = 0.59...

Background Exercise-based training programmes are commonly used to prevent sports injuries but programme effectiveness within community men's team sport is largely unknown. Objective To present the intention-to-treat analysis of injury outcomes from a clustered randomised controlled trial in community Australian football. Methods Players from 18 ma...

Objectives Determine if balance and technique training (BTT) implemented adjunct to 1,001 male Australian football (AF) players’ training influenced the activation/strength of the muscles crossing the knee during pre-planned (PpSS) and unplanned (UnSS) sidestepping. Design Randomized Control Trial. Methods Each AF player participated in either 28...

Players are the targeted end-users and beneficiaries of exercise-training programmes implemented during coach-led training sessions, and the success of programmes depends upon their active participation. Two variants of an exercise-training programme were incorporated into the regular training schedules of 40 community Australian Football teams, ov...

Military manual handling requirements range from discrete lifts to continuous and repetitive lifting tasks. For military organizations to implement a discrete lifting assessment, the assessment must be predictive of the various sub-maximum lifting tasks personnel are required to perform. This study investigated the relationship between discrete and...

Objective To determine the reach and adoption of a coach-led exercise training programme for lower limb injury prevention. Design Secondary analysis of data from a group-clustered randomised controlled trial. Setting A periodised exercise training warm-up programme was delivered to players during training sessions over an 8-week preseason (weeks 1–...

Australian football (AF) is a sport which requires a vast array of physiological qualities, including high levels of strength and power. However, the power characteristics of AF players, particularly at the sub-elite level have not been extensively studied with further investigation warranted to understand the power capabilities and training requir...

INTRODUCTION Aligning physical job requirements with physical capacities through the implementation of physical employment standards (PES) has previously been shown to improve operational effectiveness and reduce injuries (Bunch et al, 2004). In the manual handling domain, job-related tasks are grouped into two categories: muscular strength, in whi...

Anterior cruciate ligament (ACL) injury rates have increased by ∼50% over the last 10 years. These figures suggest that ACL focused research has not been effective in reducing injury rates among community level athletes. Training protocols designed to reduce ACL injury rates have been both effective (n = 3) and ineffective (n = 7). Although a ratio...

Determine if balance and technique training (BTT) implemented adjunct to normal Australian football (AF) training reduces external knee loading during sidestepping. Additionally, the authors determined if an athlete's knee joint kinematics and kinetics change over a season of AF. Eight amateur-level AF clubs (n=1,001 males) volunteered to participa...

To describe the risk and details of injuries associated with ground hardness in community level Australian football (AF). Prospective injury surveillance with periodic objective ground hardness measurement. 112 ground hardness assessments were undertaken using a Clegg hammer at nine locations across 20 grounds, over the 2007 and 2008 AF seasons. De...

Background Limited information exists about how best to conduct intervention implementation studies in community sport settings. Research should be directed towards understanding the context within which evidence-based injury prevention interventions are to be implemented, while continuing to build the evidence-base for the effectiveness of sports...