Paul Comfort

University of Salford · Centre for Health Sciences Research

A substantial body of literature has focused on weightlifting derivative lifts, primarily emphasizing the second pull phase because of its greater expression of force, velocity, and power output. The biomechanical resemblance of this phase to various athletic movements underscores the relevance of these derivatives in physical preparation across mu...

Kissick, CR, Techmanski, BS, Comfort, P, and Suchomel, TJ. The reliability, bias, differences, and agreement between velocity measurement devices during the hang clean pull. J Strength Cond Res XX(X): 000-000, 2024-This study examined the reliability, bias, differences, and agreement between the GymAware PowerTool (GA) and Tendo Power Analyzer (TEN...

The aim of this study was to assess the agreement of three different automated methods of identifying force-onset (40 N, 5 SDs, and 3 SDs) with manual identification, during the isometric mid-thigh pull (IMTP). Fourteen resistance-trained participants with >6 months experience training with the power clean volunteered to take part. After three fami...

Objectives The primary purposes were (a) to estimate the pooled effects of injury prevention programs (IPPs) on reducing overall and some specific body regions (lower extremity, thigh, knee, and ankle) injury incidence rates (IIRs) and (b) to compare the effects of single- and multi-component IPPs on mitigating injury risk in youth team sport athle...

The Nordic hamstring exercise (NHE) is effective at decreasing hamstring strain injury risk. Limited information is available on the in vivo mechanics of the bicep femoris long head (BFLH) during the NHE. Therefore, the purpose of this study was to observe kinematic, neuromuscular and in-vivo mechanics of the BFLH during the NHE. Thirteen participa...

Ripley, NJ, Barber, R, Fahey, JT, and Comfort, P. Early versus late rapid force production during single-joint isometric hamstring assessment using force plates. J Strength Cond Res XX(X): 000–000, 2024—The aim of this study was to assess differences in time-matched early versus late rapid force (RF) development in female soccer players in the 90-9...

Soriano, MA, Jiménez-Ormeño, E, Lake, JP, McMahon, JJ, Gallo-Salazar, C, Mundy, P, and Comfort, P. Kinetics and kinematics of the push press, push jerk, and split jerk. J Strength Cond Res 38(8): 1359–1365, 2024—The aim of this study was to explore the kinetics and kinematics across incremental loads with the push press (PP), push jerk (PJ), and sp...

Purpose: The aim of this investigation was to determine the reliability of normalizing rapid force (RF) production to peak force assessed during an isometric knee flexor assessment, and to present a novel method of classifying athletes' potential training needs within the 90À90 isometric hamstring assessment. Procedures: Twenty elite female soccer...

The aim of this study was to explore the reliability and feasibility of the isometric mid-thigh pull (IMTP) and dynamic strength index (DSI) in semi-professional handball players (seventeen male and eighteen female). A cross-sectional design was used to determine the test-retest reliability of several kinetic metrics registered with a force plates....

A range of field-based tests have been proposed for inclusion in physical performance assessment batteries. However, there are obvious time and human resources constraints in applied settings. The knowledge of potential relationships between tests on performance, asymmetries, as well as maturation-induced changes, may help select the most informati...

The purpose of this study was to estimate the one repetition maximum hang high pull (1RM HHP) using the peak barbell velocity of a 1RM hang power clean (HPC). Fifteen resistance-trained men (age = 25.5 ± 4.5 years, body mass = 88.3 ± 15.4 kg, height = 176.1 ± 8.5 cm, relative 1RM HPC = 1.3 ± 0.2 kg·kg-1) with previous HPC experience participated in...

Measuring the bicep femoris long head fascicle length via the use of diagnostic ultrasound has become common practice within elite sport, using single images of between 4 and 6 cm. No study to date has compared single image estimations in terms of the varying fields of view (i.e., 4, 6, and 10 cm). Therefore, the aim of this study was to determine...

The aim of this study was to compare lower limb blood flow in asymptomatic diabetic patients with early-stage peripheral artery disease (PAD) and non-diabetic controls using duplex ultrasound parameters. Duplex ultrasound (DUS) has documented high sensitivity and specificity in detecting late-stage peripheral artery Disease (PAD), both in the upper...

The aim of this study was to determine the associations between the front and back squat, countermovement jump (CMJ) and deep squat jump (DSJ) force-time metrics, and weightlifting performance in top-level weightlifters. Thirteen top-level weightlifters who classified for the World Championship 2023 participated. The heaviest successful snatch and...

Objective : This study aimed to compare the maximum and rapid force production of Spanish football players and explore the differences between age group and level of competition. Methods : A cross-sectional study was developed to evaluate the peak force (PF), relative PF, and rate of force development over 250 ms (RFD 0−250 ) during the isometric m...

A cricket wicketkeeper is a player on the fielding team positioned behind the stumps. They adopt a crouching position upon ball delivery from the bowler to take catches, execute stumpings, and limit extra runs due to byes. Wicketkeepers are advised to conduct a combination of technical and strength and conditioning training to support the dynamic a...

Considerations of the development of a strength and conditioning postgraduate course, the structure, content and learning outcomes.

Background Survival from pediatric critical illness in high‐income countries is high, and the focus now must be on optimizing the recovery of survivors. Muscle mass wasting during critical illness is problematic, so identifying factors that may reduce this is important. Therefore, the aim of this study was to examine the relationship between quadri...

Background Most rehabilitation programs use some testing to determine the readiness to return-to-sport; however, it is important to determine what the pass criteria is. One of the most common return-to-sport criteria is the limb symmetry index (LSI). Objective To investigate the differences between injured and non-injured leg in ACLR across these...

The aim of this study was to compare the effects of rest redistribution (RR) on kinetics and kinematics during the hang pull (HP). Twenty-one male athletes (age 29.5 ± 4.3 years, height 1.78 ± 0.07 m, body mass 75.17 ± 11.11 kg, relative one repetition maximum [1RM] power clean [PC] 1.17 ± 0.14 kg.kg⁻¹) performed the HP using 140% of 1RM PC with 3...

The primary aim of this study was to determine whether relative strength explains the differences in the rapid force production (force developed during first 150-, 200-, and 250 ms) of females and males, and to evaluate the relationships between peak force and rapid force production. Sixty-three team sport athletes (females: n = 25, age = 21.5 ± 1....

This systematic review investigated the job characteristics of National Collegiate Athletic Association (NCAA) strength and conditioning coaches (SCCs). Three databases were searched (Web of Science, EBSCO, and PubMed) until 12th January 2023. Eligible studies had to meet four criteria: (a) written in English, (b) published in a peer-reviewed journ...

The purpose of this study was to determine the effect of sampling frequency on the 90–90° (90-degrees hip and knee flex-ion) isometric hamstring assessment. Thirty-three elite female soccer players (age: 18.7 ± 3.7 years; height: 158.3 ± 5.9 cm; body mass: 62.8 ± 5.5 kg) performed three unilateral trials on a single occasion of the 90–90° isometric...

Background Professional rugby union is a high-intensity contact sport with position-specific high training and match volumes across a season that may lead to periods of fatigue if above a typically experienced threshold. This study assesses the influence of match play and/or training on fatigue levels in rugby union players. Objective We aimed to...

Ripley, NJ, Comfort, P, and McMahon, JJ. Relationships between modifiable risk factors of hamstring strain injury. J Strength Cond Res XX(X): 000–000, 2023—The aims of this study were to determine whether any relationship exists between eccentric hamstring strength and isokinetic strength imbalances and bicep femoris long head (BF LH ) architecture...

Calf injuries are common in professional football; thus, the establishment of reliable and time-efficient methods of measuring the peak force capabilities of the plantar flexors with equipment that is accessible to football practitioners is valuable. In this study, we determined the preliminary reliability and feasibility of a new test, termed the...

A variety of sport organizations employ sport scientists (SSs) in a range of capacities to support team operations, whereas universities employ SSs in academic (teaching and research), consulting, and support roles. Despite the growth in professional opportunities in the United States over the last few decades, little discussion has occurred to ide...

Musculoskeletal injuries are a common health problem among sporting populations. Such injuries come with a high financial burden to the involved organisations and can have a detrimental impact on the career attainment of injured individuals. Force plates are now a common tool available to sport and exercise science and medicine professionals to ena...

The good morning is a barbell exercise that can be used to develop muscular strength and hypertrophy in the posterior chain (i.e., hamstring muscles, gluteal muscles, spinal erectors, calf complex). The exercise uses a hip hinge motion with the barbell positioned across the upper trapezius, offering lifters an alternative to more common posterior c...

Background: Maximal lower-body strength can be assessed both dynamically and isometrically; however, the relationship between the changes in these 2 forms of strength following resistance training is not well understood. Purpose: To systematically review and analyze the effects of resistance training on changes in maximal dynamic (1-repetition-m...

Purpose The association between vertical jump and weightlifting performance have been well established often using discrete performance measures such as jump height or peak power which provides little insight into temporal strategies. The purpose of this investigation was to identify currently unassessed temporal countermovement jump metrics and th...

Background Load–velocity relationships are commonly used to estimate one-repetition maximums (1RMs). Proponents suggest these estimates can be obtained at high frequencies and assist with manipulating loads according to session-by-session fluctuations. Given their increasing popularity and development of associated technologies, a range of load–vel...

Meechan, D, McMahon, JJ, Suchomel, TJ, and Comfort, P. The effect of rest redistribution on kinetic and kinematic variables during the countermovement shrug. J Strength Cond Res 37(7): 1358-1366, 2023-This study compared the effects of rest redistribution (RR) on kinetic and kinematic variables during the countermovement shrug (CMS). Twenty-one mal...

Microdosing, in the context of resistance training, has increased in popularity within sporting environments where it is frequently used among strength and conditioning professionals. Although there is a clear definition for the concept within the literature, it is still commonly incorrectly used, and the extent to which microdosing has been explic...

Force plate testing is becoming more commonplace in sport due to the advent of commercially available, portable, and affordable force plate systems (i.e., hardware and software). Following the validation of the Hawkin Dynamics Inc. (HD) proprietary software in recent literature, the aim of this study was to determine the concurrent validity of the...

Comfort, P, Haff, GG, Suchomel, TJ, Soriano, MA, Pierce, KC, Hornsby, WG, Haff, EE, Sommerfield, LM, Chavda, S, Morris, SJ, Fry, AC, and Stone, MH. National Strength and Conditioning Association position statement on weightlifting for sports performance. J Strength Cond Res XX(X): 000-000, 2022-The origins of weightlifting and feats of strength spa...

Background The heights obtained during the countermovement jump and drop jump tests have been measured by numerous studies using different calculation methods and pieces of equipment. However, the differences in calculation methods and equipment used have resulted in discrepancies in jump height being reported. Objectives The aim of this systemati...

This study examined the reliability, potential bias, and practical differences between the GymAware Powertool (GA), Tendo Power Analyzer (TENDO), and Push Band 2.0 (PUSH) during the jump shrug (JS) and hang high pull (HHP) performed across a spectrum of loads. Fifteen resistance-trained men performed JS and HHP repetitions with 20, 40, 60, 80, and...

The Nordic hamstring exercise (NHE) has commonly been investigated in isolation, however, within practice multiple modalities are commonly incorporated. However, the NHE has a low level of compliance within sport, with sprinting being potentially being preferred. The present study aimed to observe the effect of a lower-limb program with either addi...

Understanding the total likely required to achieve a specific rank within a specific competition can aid in the long-and short-term preparation and tactics for performance teams. The primary objective of this investigation was to develop a set of predictive models for new weight categories across five performance zones for 3 major weightlifting com...

The main aim of cricket fielding is to minimize runs scored by the opposing batting team. This is achieved through (a) collecting a batted ball and returning it to the wicket-keeper to prevent runs from being scored, (b) dismissing a batter by catching a batted ball, (c) running a batter out by throwing the ball to strike the stumps, or 4) preventi...

The countermovement jump (CMJ) is one of the most used performance assessments in strength and conditioning. While numerous studies discuss the usability of different metrics in this test, this is often done within the context of a specific aim. However, to our knowledge, no information currently exists providing practitioners with some over-archin...

The countermovement jump (CMJ) is an important test in rugby league (RL), and the force plate is the recommended assessment device, as it permits the calculation of several variables that explain jump strategy, alongside jump height. The purpose of this study was to produce normative CMJ data and objective benchmarks for professional RL forwards an...

The aims of this study were to examine the muscle architectural, rapid force production, and force-velocity curve adaptations following 10 weeks of resistance training with either submaximal weightlifting catching (CATCH) or pulling (PULL) derivatives or pulling derivatives with phase-specific loading (OL). 27 resistance trained men were randomly a...

The effect of load on time-series data has yet to be investigated during weightlifting derivatives. This study compared the effect of load on the force-time and velocity-time curves during the countermovement shrug (CMS). Twenty-nine males performed the CMS at relative loads of 40%, 60%, 80%, 100%, 120%, and 140% one repetition maximum (1RM) power...

The purpose of this study was to examine the relationship between frontal plane knee projection angle (FPPA) and sagittal (hip and knee flexion) plane landing kinematic measures during a drop jump (DVJ) and a tuck jump assessment (TJA) test in male youth football players. Eighty-one post-pubertal male footballers were recorded performing DVJ and TJ...

This study aimed to evaluate whether lifting velocity can be used to estimate the overhead press one repetition maximum (1RM) and to explore the differences in the accuracy of the 1RM between three velocity-based methods. Twenty-seven weightlifters (16 men and 11 women) participated. The first session was used to test the overhead press 1RM. The se...

This poster was presented on 20th July 2022 at the ISBS Annual Conference 2022, in Liverpool, UK.

The aim of this study was to quantify changes in typical (i.e., jump height) and alternative (i.e., jump momentum) countermovement jump (CMJ) outcome and strategy variables, alongside maximal strength, during the early English Super League pre-season period. Twenty professional senior male rugby league players from an English Super League club perf...

This poster was presented on 7th July 2022 at the NSCA National Conference 2022, in New Orleans, Louisiana.

Soriano, MA, Jiménez-Ormeño, E, Amaro-Gahete, FJ, Haff, GG, and Comfort, P. How does lower-body and upper-body strength relate to maximum split jerk performance? J Strength Cond Res 36(8): 2102-2107, 2022-The aims of this study were to (I) determine the relationships between the maximum dynamic strength of the upper and lower body, measured by over...

Recent studies have indicated that countermovement jump (CMJ) height, reactive strength index modified, and propulsion power were larger for professional rugby league (RL) backs than forwards (McMahon et al., In-Press, Journal of Strength & Conditioning Research), but forwards produced larger takeoff momentum (MOM) (McMahon et al., 2022, PLoS ONE,...

This study aimed to investigate whether the use of short duration (SHORT) isometric mid-thigh pull (IMTP) trials resulted in greater reliability and magnitude of time-dependent force- time characteristics than traditionally performed IMTP trials (TRAD). Fourteen subjects with >six months training experience with the power clean volunteered to take...

The aim of the present study was to determine the reliability and differences between three fascicle length (FL) estimation methods when utilizing a 10-cm ultrasound (US) probe. Thirteen males (24.1 ± 3.8 years, 79.3 ± 14 kg, 179 ± 6.6 cm) participated. Bicep femoris long head (BFLH) US images were collected on two separate occasions. Three previou...

The aim of this study was to assess drop jump (DJ) performance variables (jump height, contact time, and reactive strength index) concomitant to surface electromyography (sEMG) of lower limb muscles during DJs from different drop heights (intensities). The eccentric and concentric phase sEMG from the gastrocnemius medialis, biceps femoris, and vast...

The countermovement jump (CMJ) has been suggested to be an important test of neuromuscular performance for rugby league (RL) players. Identifying force platform-derived CMJ variables that may be more applicable to RL positions (e.g., forwards and backs) has yet to be fully explored in the scientific literature. The aim of this study was to identify...

The purpose of this study was: i) to determine the reliability of alternate forms of the dynamic strength index (DSI) calculated over time-specific intervals that represent decisive actions in sport and ii) to assess the association between the original form of the DSI (DSItrad) and its variants. Twenty-three resistance-trained males (BM = 80.4 ± 1...