Jon Oliver

• Professor at Cardiff Metropolitan University

Purpose : Relative age effects and biological maturation are common biases within youth talent identification and development programs; however, their respective influence on youth weightlifting is unknown. Method : Skeletal age, determined from ultrasonography, and competitive total loads (kg) were collected in 49 national age group weightlifters...

Background Residual interlimb deficits after anterior cruciate ligament reconstruction (ACLR) can lead to functional maladaptation and increase the risk of reinjury. The tuck jump assessment (TJA) may offer a more effective evaluation of ACLR status as compared with traditional tasks owing to increased risk of altered landing mechanics, asymmetrica...

Growth and maturation have a significant influence on naturally occurring changes in performance, training-induced adaptations, injury risk, and psychosocial development and should, therefore, be important considerations within talent identification and development pathways for young weightlifters. Key stakeholders in youth weightlifting require an...

Barillas, SR, Lloyd, RS, Pedley, JS, and Oliver, JL. Different external cues elicit specific kinetic strategies during a drop jump in well-trained adolescent soccer players. J Strength Cond Res 39(1): e30-e39, 2025-The purpose of this study was to examine how different external cues that focus on jump height and ground contact time influence kineti...

This study aimed to examine the influence of different scores in the first and second half on running and explosive-based performance of elite male soccer players. Thirty-three professional players from one English Premier League team participated in the study across two consecutive seasons, 2021/22 and 2022/23. Matches were divided into half (firs...

Morris, SJ, Oliver, JL, Pedley, JS, Radnor, JM, Haff, GG, Cooper, S-M, and Lloyd, RS. Kinetic predictors of weightlifting performance in young weightlifters. J Strength Cond Res XX(X): 000–000, 2024—Relationships between force-generating capabilities and weightlifting performance ( e.g ., snatch, clean and jerk [C&J], and combined total) have previ...

Moeskops, S, Oliver, JL, Radnor, JM, Haff, GG, Myer, GD, Ramachandran, AK, Kember, LS, Pedley, JS, and Lloyd, RS. Effects of neuromuscular training on muscle architecture, isometric force production, and stretch-shortening cycle function in trained young female gymnasts. J Strength Cond Res XX(X): 000–000, 2024—This study evaluated the effects of a...

Chronic exercise training is associated with an 'athlete's artery' phenotype in young adults and an attenuated age-related decline in endothelium-dependent arterial function. Adolescence is associated with an influx of sex-specific hormones that may exert divergent effects on endothelial function, but whether training adaptations interact with biol...

Background Female athletes are four to six times more likely to sustain an anterior cruciate ligament (ACL) injury than male athletes. Jump-landing biomechanics are influenced by maturation, with post-pubertal female athletes at a heightened risk of ACL injuries. Objective The aim of our systematic review was to identify and summarise the current...

Shaw, J, Gould, ZI, Oliver, JL, and Lloyd, RS. Twelve weeks of progressive resistance training positively improves physical fitness and golf swing performance in talented youth golfers. J Strength Cond Res XX(X): 000–000, 2024—This aim of this study was to investigate the effects of a 12-week resistance training program in talented junior golfers....

Cerebral blood velocity (CBv) increases in response to moderate exercise in humans, but the magnitude of change is smaller in children compared to post-pubertal adolescents and adults. Whether sex differences exist in the anterior or posterior CBv response to exercise across pubertal development remains to be determined. We assessed middle cerebral...

Shaw, J, Gould, ZI, Oliver, JL, and Lloyd, RS. Within- and between-session reliability of golf swing variables using the TrackMan launch monitor in talented golfers. J Strength Cond Res 37(12): 2431–2437, 2023—The purpose of the current study was to establish the within- and between-session reliability of the TrackMan launch monitor to measure golf...

Background: The extent of structural cardiac remodelling in response to endurance training is maturity dependent. In adults, this structural adaptation is often associated with the adaptation of left ventricular (LV) twist mechanics. For example, an increase in LV twist often follows an expansion in end-diastolic volume, whereas a reduction in twis...

Background Male youth soccer players competing at a high level will typically engage in large volumes of soccer training from a young age. However, it is not known whether the high levels of habitual training that these high-performing players are exposed to limit their ability to respond to strength, plyometric or combined training interventions....

Golfers who want to improve their technical proficiency will undoubtedly hire a swing coach who may also influence and give advice on how the golfer can improve outside of technical enhancement (i.e. strength and conditioning, warm-ups, cool-downs etc.). With research examining the effects of strength and conditioning on youth golfers beginning to...

Global cerebral blood flow (gCBF) and cerebrovascular reactivity to hypercapnia (CVRCO2${\mathrm{CV}}{{\mathrm{R}}_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$) are modulated by gonadal hormone activity, while insulin‐like growth factor 1 facilitates exercise‐mediated cerebral angiogenesis in adults. Whether critical periods of heightened hormonal a...

Purpose; This meta-analysis aimed to 1) provide a comparison of peak changes in indirect markers of EIMD in youths versus adults and 2) determine if the involved limb moderated this effect. Method; Studies were eligible for inclusion if they 1) provided a human youth versus adult comparison, 2) provided data on muscle strength, soreness or creatine...

Kyles, A, Oliver, JL, Cahill, MJ, Lloyd, RS, and Pedley, J. Linear and change of direction repeated sprint ability tests: a systematic review. J Strength Cond Res 37(8): 1703-1717, 2023-The ability to repeatedly sprint is important in many sports, but there is no established protocol for measuring repeated sprint ability (RSA). The purpose of this...

Over the last two decades, the topic of long-term athletic development has grown in popularity within the academic literature and has influenced the structure of talent development pathways for youth athletes across many sports. The premise of long-term athletic development is salient on the habitual development of ‘athleticism’ over time to improv...

Speed and agility are fundamental locomotive skills that form the basis of many physical activities and are known to contribute to success in youth sport. Speed and agility represent unique qualities; speed refers to the ability to move quickly in a straight line, whereas agility refers to the ability to rapidly change direction in response to a st...

This book presents an integrated, research-driven, collection of 54 evidence-based chapters. Chapters are founded on the research and practical experience of 104 internationally renowned scientists and clinicians, from 25 countries. Each extensively referenced chapter concludes with a bulleted summary and where appropriate is cross-referenced to co...

INTRODUCTION: Muscular strength and plyometric ability develop naturally in youth through growth and maturation. Resistance and plyometric training have also shown a synergistic effect with natural growth processes to produce augmented performance throughout maturation. However, little is known of the natural changes in kinetic mechanisms that supp...

Neurovascular coupling (NVC) is mediated via nitric oxide signalling, which is independently influenced by sex hormones and exercise training. Whether exercise training differentially modifies NVC pre- vs. post-puberty, where levels of circulating sex hormones will differ greatly within- and between-sexes, remains to be determined. Therefore, we in...

The aim of the study was to examine the birth quartile and maturity status distributions of male academy cricketers. Participants included two hundred and thirteen junior cricket players, aged between 9 and 18 years. Players were separated into birth quartiles, and also grouped as early, average, or late maturers. For the whole cohort, there was a...

The aim of this study was to examine the effects of maturity status on drop jump (DJ) kinetics in young male athletes (categorised as early-pre [<-2.51 years], late-pre [-1.99 to-1.00 years], circa [-0.50 to 0.50 years] and post-PHV [>1.00 years]). All athletes performed a DJ from a 30 cm box onto force plates with performance variables (jump heigh...

Analysis of ground reaction forces during a drop jump can provide greater insight into stretch-shortening cycle function and jump-landing strategy than performance metrics such as jump height, ground contact time, and reactive strength index. Commercially available force plates have customized processing software capable of calculating many variabl...

Background Among youth, plyometric-jump training (PJT) may provide a safe, accessible, and time-efficient training method. Less is known on PJT effectiveness according to the maturity status. Objective This systematic review with meta-analysis set out to analyse the body of peer-reviewed articles assessing the effects of PJT on measures of physica...

While the existing literature reports strong associations between measures of physical fitness and indices of golf swing performance, such as club head speed (CHS), there is limited evidence to support this observation in youth golfers.

The aim of this systematic review with meta-analysis was to assess the available body of published peer-reviewed articles related on the effects of jump rope training (JRT) compared with active/passive controls on health- and sport-related physical fitness outcomes. Searches were conducted in three databases, including studies that satisfied the fo...

Radnor, JM, Oliver, JL, Waugh, CM, Myer, GD, and Lloyd, RS. Muscle Architecture and Maturation Influence Sprint and Jump Ability in Young Boys: A Multistudy Approach. J Strength Cond Res 36(10): 10.1519/JSC.0000000000003941-This series of experiments examined the influence of medial gastrocnemius (GM) and vastus lateralis (VL) muscle architecture (...

Apply it! After reading this article, exercise professionals will be able to: • Understand why it is useful to assess strength and power in youth. • Appreciate why it is important to consider maturity and size when assessing the strength and power of youth. • Identify different tests that can be used to assess strength and power in youth, depending...

Barillas, SR, Oliver, JL, Lloyd, RS, and Pedley, J. Kinetic responses to external cues are specific to both the type of cue and type of exercise in adolescent athletes. J Strength Cond Res XX(X): 000-000, 2022-The purpose of this study was to examine how external cues influence kinetics during isometric and dynamic tasks in adolescent athletes. Fif...

INTRODUCTION: Drop jumps (DJ) are effective screening tools for stretch-shortening cycle (SSC) function in youth. During periods of accelerated growth, it has been postulated that youth experience disturbances in neuromuscular control termed "adolescent awkwardness". However, this has predominantly been assessed using fitness performance assessment...

This cross-sectional study investigated how stretch-shortening cycle (SSC) function and kinetic variables differed between young female gymnasts of varying competitive levels. Drop jump (DJ) force-time profiles were examined in 118 female gymnasts, sub-divided by competitive level (n = 21 recreational, n = 41 regional and n = 50 elite). DJ force-ti...

Background Weightlifting training (WLT) is commonly used to improve strength, power and speed in athletes. However, to date, WLT studies have either not compared training effects against those of other training methods, or been limited by small sample sizes, which are issues that can be resolved by pooling studies in a meta-analysis. Therefore, the...

The aim of this review was to describe and summarize the scientific literature on programming parameters related to jump or plyometric training in male and female soccer players of different age and fitness levels. A literature search was conducted in the electronic databases PubMed, Web of Science and SCOPUS, using keywords related to the main top...

The purpose of this study was to examine the relationships between athletic motor skill competencies (AMSC), maturation, sex, body mass index, physical performance, and psychological constructs (motivation to exercise, physical self-efficacy, and global self-esteem). Two-hundred and twenty-four children aged 11–13 years old were included in the stu...

Purpose: This study aimed to evaluate a 10-month neuromuscular training (NMT) intervention on isometric and dynamic kinetics, standing long jump (SLJ) distance, speed and sport-specific performance. Methods: Forty-three pre-pubertal female gymnasts were allocated into either a gymnastics + NMT (gNMT; n = 16), gymnastics only (GYM, n = 15) or mat...

Cardiovascular and haematological adaptations to endurance training facilitate greater maximal oxygen consumption (V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$), and such adaptations may be augmented following puberty. Therefore, we compared left ventricular (LV) morphology (echocardiography), blood volume, haemoglobin (Hb) mass (CO rebreathi...

Read, PJ, Pedley, JS, Eirug, I, Sideris, V, and Oliver, JL. Impaired stretch-shortening cycle function persists despite improvements in reactive strength followingafter anterior cruciate ligament reconstruction. J Strength Cond Res 36(5): 1238-1244, 2022-Reactive strength index (RSI) during a single-leg drop jump (SLDJ) has been indicated to determ...

This study aimed to: (1) examine differences in physical performance across birth-quartiles and maturity-status, and (2) determine the relationships among relative age, maturation and physical performance in young male soccer players. The sample included 199 males aged between 8.1 and 18.9 years, from two professional soccer academies in the Englis...

In the sport of golf, club head speed has been associated with higher skill levels in golfers and lower overall scoring. Research has shown that club head speed is an important measure of golf swing performance that can be enhanced with appropriate strength and conditioning interventions. Understanding the determinants of club head speed can help i...

This study aims to determine whether motor coordination influences the perception-decision time (perceptual-cognitive factor) and movement response time (physical factor) of young soccer players in a sport-specific agility task regardless of maturation. Eighty-seven young male soccer players were analysed. Anthropometric measurements were used to d...

Purpose: To conduct a systematic review and meta-analysis of epidemiological data of injuries in male and female youth football players. Methods: Searches were performed in MEDLINE/PubMed, Web of Science, Cochrane Library, and SPORTDiscus databases. Studies were considered if they reported injury incidence rate among male and female youth (≤19 yea...

Leading health organizations and long- term athletic development models have identified the need to develop movement competencies in children and adolescents. The athletic motor skill competencies (AMSCs) have been identified as key skills that form the foundations of all athletic movements. The AMSCs form an integral part of the long-term athletic...

Background Youth populations benefit from neuromuscular training; however, the extent to which training frequency, baseline fitness, and maturity status moderate the response to long-term neuromuscular training in male youth remains unclear. Hypothesis Twice-weekly training (G2x) would induce larger improvements in movement competency and strength...

The aims of the current study were to i) investigate differences in maximal rebound jump kinetics in boys at different stages of maturity, and ii) determine the relationship of muscle architecture characteristics to maximal rebound jump kinetics. One hundred twenty-seven male, secondary school children were categorised into maturity groups (pre-, c...

Early sport specialization involves physically immature children participating in intensive year-round training and/or competition for a single sport. The lack of sport exposure and diversification during the developmental years may underlie the increased risk of overuse injuries, blunting of motor skill development, psychosocial issues, overtraini...

The stretch‐shortening cycle (SSC) assists in effective force attenuation upon landing and augments force generation at take‐off during a drop vertical jump (DVJ). General performance outcomes such as jump height or peak measures have been used to assess SSC function in youth populations; however, these discrete metrics fail to provide insight into...

Verbal cues are tools used by practitioners in developing a youth athlete's motor skill abilities. External cues may optimize athletic performance and movement competencies in adults with trends for youth athletic populations following suit. However, maturation, training age, and cognitive age may interact with the efficacy of cues used. To better...

The purpose of this study was to investigate the landscape of Fundamental Movement Skills (FMS) and strength development in professional football (soccer) academies in the UK. To achieve this, we interviewed 16 participants, whose primary responsibility was the physical development of youth players from a variety of Elite Player Performance Plan (E...

The purpose of this article is to provide an overview of the growth, maturation and resistance training-related changes in muscle-tendon and neuromuscular mechanisms in youth, and the subsequent effect on performance. Sprinting, jumping, kicking, and throwing are common movements in sport that have been shown to develop naturally with age, with imp...

Objectives To determine the inter-rater and intra-rater reliability of frontal and sagittal plane landing kinematic measures during drop jump (DVJ) and tuck jump (TJA) tasks in male youth soccer players, to assess the concurrent validity between DVJ and TJA tests, and to evaluate the ability of both tasks to detect differences between players’ stag...

Lloyd, RS, Howard, SW, Pedley, JS, Read, PJ, Gould, ZI, and Oliver, JL. The acute effects of accentuated eccentric loading on drop jump kinetics in adolescent athletes. J Strength Cond Res 36(9): 2381-2386, 2022-The purpose of the study was to determine the acute effects of accentuated eccentric loading (AEL) on drop jump kinetics in adolescent ath...

PurposeNeuromuscular training aims to enhance motor skill competency and increase muscle strength. However, the effectiveness of short-duration interventions focused on addressing lower limb injury risk factors in male youth athletes at different stages of maturity remains unknown.Methods Forty-eight young male academy cricket players [pre-peak hei...

Despite previous misconceptions, youth participation in weightlifting is now recognized as safe and beneficial when delivered, programed, and monitored by a qualified professional. This article explores teaching progressions to help coaches periodize weightlifting training for young or novice athletes, with consideration to the theoretical concepts...

Context Arbitrary asymmetry thresholds are regularly used in professional soccer athletes, notwithstanding the sparse literature available to examine their prevalence. Objective To establish normative and positional asymmetry values for commonly used screening tests and investigate their relationships with jumping performance. Design Cross-sectio...

Synergistic development of muscular strength and motor skill competency is central to long-term athletic development. However, these qualities need to be developed in a logical and progressive manner, and training methods need to be developmentally appropriate, engaging, and enjoyable for young athletes to help them build a positive association wit...

Pedley, JS, Lloyd, RS, Read, PJ, Moore, IS, Myer, GD, and Oliver, JL. A novel method to categorize stretch-shortening cycle performance across maturity in youth soccer players. J Strength Cond Res XX(X): 000-000, 2020-This study used a novel method to categorize stretch-shortening cycle (SSC) function during a drop jump (DJ) using the force-time cu...

Strength and conditioning provision for young athletes offers unique challenges and opportunities for coaches. Periods of rapid and nonuniform growth in skeletal structures can result in temporary reductions in athletic performance and heightened injury risk. Despite the increased risk of injury in young athletes, surprisingly, there is often a lac...

Purpose Jump-landing assessments provide a means to quantify an individual’s ability to attenuate ground reaction forces, generate lower limb explosive power and maintain joint alignment. In order to identify risk factors that can be targeted through appropriate training interventions, it is necessary to establish which (scalar) objective kinetic,...

Context: Single-leg hop tests are used to assess functional performance following anterior cruciate ligament (ACL) reconstruction. Recording 6-m timed hop scores using a stopwatch increases the potential for misclassification of patient status due to the number of error sources present. Objective: To examine the consistency of pass/fail (>90% li...

Leading global physical activity guidelines advocate that young children need to engage in activities that strengthen musculoskeletal tissues and improve movement skill competency. The purpose of this study was to examine the effects of delivering strength and conditioning as part of the physical education curriculum on athletic motor skill compete...

Background The triple hop for distance test commonly uses a limb symmetry index (LSI) ‘pass’ threshold of > 90% for total hop distance following anterior cruciate ligament reconstruction (ACLR). However, understanding the manner in which athletes generate and dissipate forces during consecutive hops within the test may provide greater insight into...

Cahill, MJ, Oliver, JL, Cronin, JB, Clark, K, Cross, MR, Lloyd, RS, and Lee, JE. Influence of resisted sled-pull training on the sprint force-velocity profile of male high-school athletes. J Strength Cond Res XX(X): 000-000, 2020-Although resisted sled towing is a commonly used method of sprint-specific training, little uniformity exists around tra...

PurposeThis cross-sectional study investigated dynamic force–time variables and vaulting performance in young female gymnasts of different maturity status.Methods120 gymnasts aged 5–14 years were sub-divided into maturity groupings using percent of predicted adult height (%PAH) attained. Participants performed three jumping protocols, the squat jum...

An understanding of how movement competency, strength, and power interacts with natural growth and maturation is required in order to determine meaningful changes with developing athletes. Isometric and dynamic testing in youth athletes provide insight into the natural development of the force‐velocity (F‐V) spectrum. Two‐hundred and six young male...

PURPOSE To examine the effects of a 9-month NMT intervention on isometric and dynamic force-time characteristics during strength and power tests and vertical takeoff velocity during gymnastics vaulting. METHODS Forty-three pre-pubertal female gymnasts were subdivided into gymnastics + NMT (GYM+NMT; n = 16), gymnastics only (GYM, n = 15) groups and...

Objectives Examine growth and maturation trends in dynamic balance using the anterior reach Y-Balance test, and its utility as an injury risk screening tool. Design Cross sectional and prospective cohort. Setting Elite male youth soccer players. Participants 346 players grouped as pre, circa or post peak height velocity (PHV). Main outcome meas...

An investigation of the effects of different training types on back squat performance and how changes in back squat performance influence changes in athletic motor skills.

There is a renewed interest is resisted sled training (RST); however, little uniformity exists regarding the integration of best practices in RST for young athletes. This article reviews the prescription of load, methods of RST, and the integration of sprint-specific periodized training blocks during the preparatory phase to elicit the greatest gai...

Speed is an important athletic quality and needs to be developed in young athletes, this may be best achieved using specific forms of sprint training. Resisted sled training is a sprint specific form of training widely used by coaches and practitioners. The two modes of resisted sled training that exist are sled pushing and pulling, with limited re...

Moeskops, S, Oliver, JL, Read, PJ, Cronin, JB, Myer, GD, Haff, GG, and Lloyd, RS. The influence of biological maturity and competitive level on isometric force-time curve variables and vaulting performance in young female gymnasts. J Strength Cond Res XX(X): 000-000, 2020-This cross-sectional study investigated isometric force-time curve variables...

Objectives The purpose of this study was to examine whether the use of machine learning improved the ability of a neuromuscular screen to identify injury risk factors in elite male youth football players. Methods 355 elite youth football players aged 10–18 years old completed a prospective pre-season neuromuscular screen that included anthropometr...

Purpose: To determine the differences in muscle architecture of the lower limb in pre-peak height velocity (PHV), circa-PHV, and post-PHV boys. Method: Muscle architecture variables from both the gastrocnemius medialis (GM) and vastus lateralis (VL) were derived from ultrasonographic images in 126 school-aged boys. One-way analysis of variance u...

Dobbs, IJ, Oliver, JL, Wong, MA, Moore, IS, and Lloyd, RS. Effects of a 12-week training program on isometric and dynamic force-time characteristics in pre- and post-peak height velocity male athletes. J Strength Cond Res XX(X): 000-000, 2019-Literature shows that training children and adolescents can enhance strength and power irrespective of thei...

Purpose: To quantify speed, peak momentum, standing long jump (SLJ), and the ratio of vertical to horizontal take-off velocity (Ratiovert-hori TOV) in young female gymnasts of different maturity status and their influence on vaulting vertical TOV. Methods: One hundred twenty gymnasts age 5-14 years were subdivided into maturity groupings using p...

Sled pushing is a commonly used form of resisted sprint training, however little empirical evidence exists, especially in youth populations. The aim of this study was to assess the effectiveness of unresisted and resisted sled pushing across multiple loads. Fifty high school athletes were assigned to an unresisted (n=12), or 3 resisted groups; ligh...

Objective: Determine how lower limb neuromuscular control changes over the course of a competitive soccer season. Design: Repeated measures. Setting: Academy soccer club. Participants: 43 male youth soccer players (age 13.1 ± 2.2 yr; height 160.1 ± 15.7 cm; body mass 49.4 ± 14.3 kg; maturity offset 0.2 ± 1.9 yr). Main outcome measures: Pre...

Cahill, M, Oliver, JL, Cronin, JB, Clark, K, Cross, MR, and Lloyd, RS. Sled-push load-velocity profiling and implications for sprint training prescription in young athletes. J Strength Cond Res XX(X): 000-000, 2019-Resisted sled pushing is a popular method of sprint-specific training; however, little evidence exists to support the prescription of r...

This study aimed to examine the extent to which maturity offset, strength, and movement competency influences motor skill performance in adolescent boys. One hundred and eight secondary school boys completed anthropometric and physical testing on two non-consecutive days for the following variables: Maturity offset, isometric mid-thigh pull absolut...