Christopher Thomas

Changes of direction (CODs) are key manoeuvres linked to decisive moments in sport and are also key actions associated with lower limb injuries. During sport athletes perform a diverse range of CODs, from various approach velocities and angles, thus the ability to change direction safely and quickly is of great interest. To our knowledge, a compreh...

Objective: To assess the validity of the cutting movement assessment score (CMAS) to estimate the magnitude of peak knee abduction moments (KAM) against three-dimensional (3D) motion analysis, while comparing whole-body kinetics and kinematics between subjects of low (bottom 33%) and high CMASs (top 33%). Design: Cross-sectional study. Setting:...

Dos'Santos, T, McBurnie, A, Thomas, C, Comfort, P, and Jones, PA. Biomechanical determinants of the modified and traditional 505 change of direction speed test. J Strength Cond Res XX(X): 000-000, 2019-The aim of this study was to investigate the whole-body biomechanical determinants of 180° change of direction (COD) performance. Sixty-one male ath...

Thomas, C, Dos'Santos, T, Comfort, P, and Jones, PA. Effect of asymmetry on biomechanical characteristics during 180° change of direction. J Strength Cond Res XX(X): 000-000, 2020-The aim of this study was to explore the effect of asymmetry on biomechanical characteristics during two 180° change of direction (CoD) tasks (505 and modified 505 [505mo...

Attacking agility actions, such as side steps, shuffle steps, crossover cutting, split steps, spins, decelerations, and sharp turns, are important maneuvers in invasion team sports, often linked with decisive match winning moments. Generally, the aims of these actions are to (a) evade and create separation from an opponent, (b) generate high exit v...

The purpose of this study was to compare countermovement jump force–time measures between strength-matched male and female soccer players. Males (n = 11) and females (n = 11) were strength-matched via isometric mid-thigh pull testing, whereby peak force values were normalised to body mass. Subjects performed three maximal-effort countermovement jum...

Background Most cutting biomechanical studies investigate performance and knee joint load determinants independently. This is surprising because cutting is an important action linked to performance and non-contact anterior cruciate ligament (ACL) injuries. The aim of this study was to investigate the relationship between cutting biomechanics and cu...

The aim of this was study to examine the inter-task relationships and compare change of direction (COD) biomechanics between different angles (45°, 90°, and 180°). Twenty-seven men performed three COD tasks, whereby lower-limb and trunk kinematics and kinetics were assessed via 3D motion and ground reaction force (GRF) analysis. Key mechanical diff...

Dos'Santos, T, Thomas, C, Comfort, P, and Jones, PA. Biomechanical effects of a 6-week change-of-direction technique modification intervention on anterior cruciate ligament injury risk. J Strength Cond Res XX(X): 000-000, 2021-The aim of this study was to evaluate the biomechanical effects of a 6-week change-of-direction (COD) technique modificatio...

Abstract: This study aimed to examine the effects of change of direction (COD) speed and technique modification training on 180� turning performance (completion time, ground contact time [GCT], and exit velocity), kinetics, and kinematics. A non-randomised 6 week intervention study was administered. Thirteen male multidirectional sport athletes for...

Side-step cutting is an action associated with non-contact anterior cruciate ligament (ACL) injury with a plethora of negative economical, health, and psychological implications. Although ACL injury risk factors are multifactorial, biomechanical and neuromuscular deficits which contribute to “high-risk” and aberrant movement patterns are linked to...

Thomas, C, Dos'Santos, T, Warmenhoven, J, and Jones, PA. Between-limb differences during 180° turns in female soccer players: application of statistical parametric mapping. J Strength Cond Res 36(11): 3136-3142, 2022-This study was exploratory in nature and investigated the ability of statistical parametric mapping (SPM) to assess between-limb diff...

Dos'Santos, T, Thomas, C, Comfort, P, and Jones, PA. Biomechanical effects of a 6-week change of direction speed and technique modification intervention: implications for change of direction side step performance. J Strength Cond Res XX(X): 000-000, 2020-The aim of this study was to evaluate the biomechanical effects of change of direction (COD) sp...

The aim of the study was to compare ground reaction force (GRF) characteristics between the antepenultimate foot contact (APFC), penultimate foot contact (PFC), and final foot contact (FFC), and to examine the relationships between APFC, PFC, and FFC GRF characteristics with 505 change of direction (COD) speed performance. Twenty university male so...

Change of direction manoeuvres is important in soccer and associated with non-contact anterior cruciate ligament injury, yet it is not known how the mechanics differentiate between males and females during 180° turns. Twenty-eight soccer players (14 males and 14 females) performed 180° turns with ground reaction forces collected over penultimate an...

The investigation of inter-limb asymmetries has increased in recent years, with practitioners and researchers typically exploring the impact of inter-limb asymmetry on athletic performance, screening inter-limb asymmetry in relation to injury risk, and monitoring of inter-limb asymmetry during injury rehabilitation. A contentious issue regarding th...

Comfort, P, Jones, PA, Thomas, C, Dos'Santos, T, McMahon, JJ, and Suchomel, TJ. Changes in early and maximal isometric force production in response to moderate- and high-load strength and power training. J Strength Cond Res XX(X): 000-000, 2020-The aims of this study were to determine the changes in early (50-, 100-, 150-, 200-, 250 ms) and maximal...

Change of direction (COD) manoeuvres are associated with anterior cruciate ligament (ACL) injury risk due to the propensity to generate large multiplanar knee joint loads. Given the short- and long-term consequences of ACL injury, practitioners are interested in methods that reduce knee joint loads and subsequent ACL loading. An effective strategy...

The purpose of this study was to explore whether limb preference influences braking strategy and knee joint mechanics during a 180° pivot task in female soccer players (mean ± SD; age = 20.6 ± 0.6 years; height = 165 ± 7.0 cm; body mass = 56.6 ± 6.3 kg). Three-dimensional motion analyses of pivoting on the preferred and non-preferred kicking limbs...

Objective: To critically evaluate the effect of limb dominance on change of direction (COD) biomechanics associated with increased ACL injury-risk. Methods: A systematic review of the literature was conducted using Medline and Sport DISCUS databases. Studies that compared COD biomechanics (lower-limb/whole-body kinetics/kinematics) between limbs...

Abstract Cutting actions are important maneuvers in multidirectional sport and are also key actions associated with non-contact anterior cruciate ligament injury; however, it is important to note that three primary cutting techniques have been studied within the literature: the side-step, crossover cut, and split-step. These cutting techniques demo...

Purpose: Skeletal-muscle function can be evaluated using force-times curves generated via the isometric midthigh pull (IMTP). Various sampling frequencies (500-1000 Hz) have been used for IMTP assessments; however, no research has investigated the influence of sampling frequency on IMTP kinetics. Therefore, the purpose of this study was to investi...

The primary aim of this investigation was to determine the effects of a four-week period of in-season strength training on the dynamic strength index (DSI). Pre and post a four-week period of strength-based training, twenty-four collegiate athletes (age = 19.9 ± 1.3 years; height = 1.70 ± 0.11 m; weight 68.1 ± 11.8 kg) performed three isometric mid...

The purpose of this study was twofold: (1) to examine differences in change of direction (COD) performance and asymmetries between team-sports while considering the effects of sex and sport; (2) to evaluate the relationship between linear speed, COD completion time, and COD deficit. A total of 115 (56 males, 59 females) athletes active in cricket,...

Previous studies have reported an association between global measures of bilateral strength and change of direction (COD) ability. Yet, little is known about the association between unilateral muscle strength qualities and COD ability. The aim of this study was to explore the associations between unilateral muscle strength qualities and COD measure...

Comfort, P, Dos'Santos, T, Thomas, C, McMahon, JJ, and Suchomel, TJ. An investigation into the effects of excluding the catch phase of the power clean on force-time characteristics during isometric and dynamic tasks: an intervention study. J Strength Cond Res XX(X): 000-000, 2018-The aims of this study were to compare the effects of the exclusion o...

The aims of this study were to quantify asymmetries in change of direction (COD) performance via completion time and COD deficit, and determine its influence on asymmetry profiling of COD ability. A secondary aim was to evaluate the relationship between linear speed, 505 time and COD deficit. Forty-three youth netball athletes (age: 15.4 ± 1.1 year...

The purpose of this study was to determine the impact of between limb asymmetries in IMTP force-time characteristics on change of direction speed (CODS). Twenty multisport collegiate athletes (mean ± SD: age: 21.0 ± 1.9 years; mass: 78.7 ± 8.9 kg; height: 1.77 ± 0.04 m) performed three unilateral stance IMTP trials per limb and three modified 505 C...

Cuthbert, M, Thomas, C, Dos'Santos, T, and Jones, PA. Application of change of direction deficit to evaluate cutting ability. J Strength Cond Res 33(8): 2138-2144, 2019-The purpose of this study was to examine the application of the change of direction deficit (CODD) to a 90° cut test to examine whether CODD provides a unique evaluation of an indiv...

Peak force and impulse recorded from a unilateral stance isometric mid-thigh pull are reliable methods of assessing unilateral isometric force production capabilities (ICC ≥0.85; CV ≤9%). In contrast, RFD demonstrated lower reliability (ICC = ≤0.79; CV = ≥19%). ABSTRACT The aim of this study was to determine the between-session reliability of the u...

The purpose of this study was to examine the differences in countermovement jump peak force (CMJ-PF), isometric mid-thigh pull peak force (IMTP-PF), and resultant dynamic strength index (DSI) values between team-sport athletes. One hundred and fifteen male and female team-sport athletes performed the CMJ and IMTP to determine peak force (CMJ-PF and...

The purpose of this study was to explore the relationships between isometric mid-thigh pull (IMTP) force-time characteristics (peak force and time-specific force vales (100–250 ms)) and dynamic performance and compare dynamic performance between stronger and weaker athletes. Forty-three athletes from different sports (rowing, soccer, bicycle motocr...

The aims of this study were: 1) to compare the strongest (D) and weakest (ND) limbs in determining muscle strength asymmetry (MSA) ratios among various muscle strength qualities and 2) to determine the relationships among various muscle strength qualities. 17 youth male basketball athletes (age=17.5±0.8 years; height=187.1±9.4 cm; body mass=81.4±10...

The countermovement jump (CMJ) and isometric mid-thigh pull (IMTP) are commonly used to compare one’s force capacity during dynamic and isometric assessments, respectively. However, little research has investigated the influence of maximum isometric strength on drop-jump (DJ) performance. Therefore, the purpose of this study was to explore differen...

Purpose: To investigate (a) the relationships between maximal isometric strength, vertical jump (VJ), sprint speed, and change of direction speed (CODS) in academy netball players, and (b) determine whether players who have high performance in isometric strength testing would demonstrate superior performance in VJ, sprint speed, and CODS measures....

Objectives: To determine the impact of between limb asymmetries in hop performance on change of direction speed (CODS). Design and Methods: Twenty-two multisport collegiate athletes (mean ± SD; age: 21.8 ± 3.4 years, height: 178.1 ± 6.7 cm, mass: 73.5 ± 7.1kg) performed three single and triple horizontal hops for distance per limb, followed by thre...

Purpose: To determine the reliability and variability of dynamic strength index (DSI) calculated from squat jump (SJ) (DSI-SJ) versus countermovement jump (CMJ) (DSI-CMJ) peak force (PF) and to compare DSI values between methods. Methods: Male youth soccer and rugby league players (n = 27; age = 17.2 ± 0.7 years; height = 173.9 ± 5.7 cm; body ma...

The aims of this study were to compare isometric mid-thigh pull (IMTP) peak force (PF), time-specific force values (100-, 150- and 200 ms), rate of force development (RFD) at pre-determined time bands (0-100, 0-150 and 0-200 ms) and net forces between two commonly adopted hip joint angles (145˚[hip145] and 175˚[hip175]) with a 145˚ standardised kne...

Previous studies have reported an association between eccentric strength (ECC-STR) and change of direction (COD) ability. Little is known about how ECC-STR facilitates COD maneuvers. The aim of this study was to examine the role of ECC-STR during a 180° COD task in 18 female soccer players. Each player performed six trials of a 180° COD task whereb...

The purpose of this study was to evaluate the height, body mass and physical characteristics of female academy netball players by position (centers, defenders and shooters). Data were collected on 43 regional academy players during the preseason period and comprised of height and body mass, and physical characteristics (single-leg hop [SLH], squat...

THERE IS A LACK OF STRENGTH AND CONDITIONING RESEARCH INTO THE DEMANDS AND THE SPECIFIC AREAS OF DEVELOPMENT REQUIRED TO OPTIMIZE PERFOR- MANCE AND REDUCE THE RISK OF COMMON INJURIES IN FEMALE NETBALL ATHLETES. NETBALL IS PREDOMINANTLY ANAEROBIC, CHARACTERIZED BY FREQUENT HIGH-INTENSITY MOVEMENTS THAT REQUIRE HIGH LEVELS OF STRENGTH, POWER, AND LOW...

The purpose of this study was to investigate the between-session reliability of common strength- and power-related measures in adolescent athletes. Seventeen adolescent athletes (males: n = 8: age 17.1 ± 2.2 years; height 175.6 ± 3.5 cm; mass 80.2 ± 3.6 kg; females: n = 9; age 16.9 ± 2.6 years; height 178.5 ± 4.3 cm; mass 71.5 ± 4.5 kg) participate...

The aim of the study was to determine the between-session reliability of isometric mid-thigh pull (IMTP) kinetics and maximal weight lifted during the power clean (PC) in male youth soccer players, and to identify the smallest detectable differences between sessions. Thirteen male youth soccer players (age: 16.7 ± 0.5 years, height: 1.80 ± 0.08 m,...

Various thresholds have been used to identify the onset of contraction during isometric mid-thigh pull (IMTP) however, no agreed onset threshold exists for this assessment. The purpose of this study was to compare relative body weight (BW) and arbitrary onset thresholds to a criterion onset threshold 5 SD of BW for IMTP force-time variables; force...

Purpose: The purpose of this study was to investigate the within-session reliability of bilateral and unilateral stance isometric mid-thigh pull (IMTP) force-time characteristics including peak force (PF), relative PF and impulse at time bands (0-100, 0-200, 0-250 and 0-300 ms); and to compare isometric force-time characteristics between right and...

Objectives: The purpose of this study was to evaluate the height, body mass and physical characteristics of English regional academy netball players by age category (under 15s, under 17s and under 19s). Design and Methods: Data were collected on 50 regional academy players during the preseason period and comprised of height, body mass, and physical...

Objectives: The aim of this investigation was to determine the relationships between isometric strength, sprint, and change of direction speed (CODS) performance in academy cricketers. Design and Methods: Eighteen male academy cricketers (mean ± SD; age = 17.1 ± 0.7 years; height = 175.8 ± 6.1 cm; mass = 71.7 ± 11.3 kg) performed tests of bilateral...

Mechanical variables during change of directions for example braking and propulsive forces, impulses and ground contact times (GCT) have been identified as determinants of faster change of direction speed (CODS) performance. The purpose of this study was to investigate the mechanical determinants of 180° CODS performance with mechanical characteris...

Context: Regular performance (~2 x week) of Nordic curls has been shown to increase hamstring strength and reduce the risk of hamstring strain injury, although no consensus on ankle position has been provided. Objective: The aim of this study was to compare the effects of performing Nordic curls, with the ankle in a dorsiflexed (DF) or plantar f...

To determine the reliability of the 505 change of direction (COD) test performed with both a stationary and flying start. Fifty-two female netball players (age 23.9 ± 5.4 yrs, height 169.9 ± 3.3 cm, body mass 65.2 ± 4.6 kg) performed 6 trials of the 505 COD test, three with a flying start and three with a stationary start, once per week over a four...

Research has demonstrated a clear relationship between dynamic strength and vertical jump performance; however, the relationship of isometric strength and vertical jump performance has been studied less extensively. The aim of this study was to determine the relationship between isometric strength and performance during the squat jump (SJ) and coun...

Skeletal muscle function can be evaluated using force-times curves generated via the isometric mid-thigh pull (IMTP). Various sampling frequencies (500-1000 Hz) have been used for IMTP assessments; however no research has investigated the influence of sampling frequency on IMTP kinetics. Therefore, the purpose of this study was to investigate the i...

Purpose: To determine the reliability of the Dynamic Strength Index (DSI) in college athletes. Method: Nineteen male college athletes performed the squat jump (SJ) and isometric midthigh pull (IMTP) to determine peak force, on 2 separate days. Reliability was assessed by intraclass correlation coefficient (ICC), typical error (TE), percentage ch...

The purpose of this investigation was to determine the reliability of the 30-15 Intermittent Fitness Test (30-15IFT) in semi-professional soccer players. Fourteen male semi-professional soccer players performed the 30-15IFT on two occasions, separated by 7 days. Reliability was assessed by intraclass correlation coefficient (ICC), typical error of...

Objectives: The aim of this investigation was to assess the use of isometric strength testing as a determinant of sprint and change of direction performance in collegiate athletes. Design and Methods: Fourteen male collegiate athletes (mean ± SD; age = 21 ± 2.4 years; height =176 ± 9.0 cm; body mass = 72.8 ± 9.4 kg) participated in the study. Maxim...

This study aimed to examine performance changes in lacrosse players during a 24-week competitive season (including 22 weeks of periodized resistance training (RT)). Eleven male lacrosse players (age 24.5 ± 4.3 years, height 180.4 ± 5.6 cm, body mass 80.5 ± 5.7 kg, 1 repetition maximum (1RM) back squat (BS) 113.3 ± 17.8 kg, 1RM power clean (PC) 67.2...