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Strength and Power Training in Rehabilitation: Underpinning Principles and Practical Strategies to Return Athletes to High Performance

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Injuries have a detrimental impact on team and individual athletic performance. Deficits in maximal strength, rate of force development (RFD), and reactive strength are commonly reported following several musculoskeletal injuries. This article first examines the available literature to identify common deficits in fundamental physical qualities following injury, specifically strength, rate of force development and reactive strength. Secondly, evidence-based strategies to target a resolution of these residual deficits will be discussed to reduce the risk of future injury. Examples to enhance practical application and training programmes have also been provided to show how these can be addressed.
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Sports Medicine (2020) 50:239–252
Strength andPower Training inRehabilitation: Underpinning
Principles andPractical Strategies toReturn Athletes toHigh
LucaMaestroni1,2 · PaulRead3· ChrisBishop4· AnthonyTurner4
Published online: 26 September 2019
© Springer Nature Switzerland AG 2019
Injuries have a detrimental impact on team and individual athletic performance. Deficits in maximal strength, rate of force
development (RFD), and reactive strength are commonly reported following several musculoskeletal injuries. This article first
examines the available literature to identify common deficits in fundamental physical qualities following injury, specifically
strength, rate of force development and reactive strength. Secondly, evidence-based strategies to target a resolution of these
residual deficits will be discussed to reduce the risk of future injury. Examples to enhance practical application and training
programmes have also been provided to show how these can be addressed.
* Luca Maestroni
Paul Read
Chris Bishop
Anthony Turner
1 Smuoviti, Viale Giulio Cesare, 29, 24121Bergamo, BG,
2 StudioErre, Via della Badia, 18, 25127Brescia, BS, Italy
3 Athlete Health andPerformance Research Center, Aspetar
Orthopaedic andSports Medicine Hospital, Doha, Qatar
4 London Sport Institute, School ofScience andTechnology,
Middlesex University, Greenlands Lane, London, UK
Key Points
Residual deficits in maximal strength, rate of force devel-
opment and reactive strength are documented following
musculoskeletal injury.
Targeting these residual deficits following injury can
reduce the risk of future injury as a means of tertiary
Rehabilitation should prepare athletic populations to
tolerate loads and velocities across the full spectrum of
the force–velocity curve and this is essential for return-
ing injured athletes to high performance levels.
1 Introduction
Injuries have a detrimental impact on team and individual
athletic performance, with increased player availability
improving the chances of success [1]. The available data
suggest an interaction between injury, performance, physi-
cal outputs, and success at both team and individual levels
[24]. It seems logical that all staff involved should strive
to work together in an interdisciplinary fashion to prevent
injuries and to improve performance. Furthermore, several
studies have reported that a previous injury may increase the
risk for subsequent injuries [510]. This raises the question
of whether persistent deficits have been fully assessed and
targeted before athletes return to play (RTP), and if a greater
emphasis should be placed on a return to performance strat-
egy as a means of tertiary prevention [11].
Following the occurrence of injury or pain onset, defi-
cits in strength [1216], strength ratios [17], rate of force
development [1823], reactive strength [2426], leg stiff-
ness [2731], and peak power [3234], have all been shown
in athletic populations. Equally, these same attributes are
widely considered important physical performance deter-
minants in high-performance sport [35, 36]. In spite of this,
rehabilitation programmes often adopted in research and
clinical practice are mainly focused on restoring strength
[3740], which by definition, consists of high forces at low
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... This work could help optimize interventions to address lingering motor control deficits despite current recommended clinical practice. Interestingly, strength training literature has shown that training with heavy loads (>80% of 1 repetition maximum) increased neural drive; in addition, intent to move weight quickly and ballistic power training methods have helped increase rate of force development by lowering MU recruitment thresholds (43). Such interventions could be considered to determine utility to address AMI in both ipsilateral and contralateral limbs after ACL injury. ...
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Introduction It is well documented that marked weakness of the quadriceps is present after knee joint injury. This joint trauma induces a presynaptic reflex inhibition of musculature surrounding the joint, termed arthrogenic muscle inhibition (AMI). The extent to which anterior cruciate ligament (ACL) injury affects thigh musculature motor unit activity, which may affect restoration of thigh muscle strength after injury, is undetermined. Methods A randomized protocol of knee flexion and extension isometric contractions (10%–50% maximal voluntary isometric contraction) were performed for each leg on 54 subjects with electromyography array electrodes placed on the vastus medialis, vastus lateralis, semitendinosus, and biceps femoris. Longitudinal assessments for motor unit recruitment and average firing rate were acquired at 6-month intervals for 1 year post ACL injury. Results The ACL-injured population demonstrated smaller quadriceps and hamstrings motor unit size (assessed via motor unit action potential peak-to-peak amplitude) and altered firing rate activity in both injured and uninjured limbs compared to healthy controls. Motor unit activity remained altered compared to healthy controls at 12 months post ACL reconstruction (ACLR). Discussion Motor unit activity was altered after ACLR up to 12 months post-surgery. Further research is warranted to optimize rehabilitation interventions that adequately address altered motor unit activity and improve safety and success with return to sport after ACLR. In the interim, evidence based clinical reasoning with a focus on development of muscular strength and power capacity should be the impetus behind rehabilitation programming to address motor control deficits.
... The available meta-analyses focused on the effects of PJT on vertical jump height (e.g., drop jump height) without assessing the specific effects of PJT on the RSI [33,34]. Similarly, previous reviews analysed training-induced effects on the RSI, although: (1) there was a focus on a myriad of strength and conditioning methods without examining single-mode PJT effects, (2) these studies examined specific populations (e.g., endurance runners; post-rehabilitation athletes; males), and (3) some studies were biased in their systematic review and/or meta-analytical approach (e.g., single-control group sample size not proportionately divided in studies including multiple-intervention groups) [2,21,[35][36][37][38][39][40][41]. Additionally, the potential role of moderators such as participants' sex, age, and sport, have not been addressed in a meta-analytical approach. ...
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Background: The reactive strength index (RSI) is meaningfully associated with independent markers of athletic (e.g., linear sprint speed) and neuromuscular performance (e.g., stretch-shortening-cycle [SSC]). Plyometric jump training (PJT) is particularly suitable to improve the RSI due to exercises performed in the SSC. However, no literature review has attempted to meta-analyse the large number of studies regarding the potential effects of PJT on the RSI in healthy individuals across the lifespan. Aim: The aim of this systematic review with meta-analysis was to examine the effects of PJT on the RSI of healthy individuals across the lifespan compared with active/specific-active controls. Methods: Three electronic databases (PubMed, Scopus, WoS) were searched up to May 2022. According to the PICOS approach, the eligibility criteria were: i) healthy participants, ii) PJT interventions of ≥3 weeks, iii) active (e.g., athletes involved in standard training) and specific-active (e.g., individuals using heavy resistance training) control group(s), iv) a measure of jump-based RSI pre-post training, and v) controlled studies with multi-groups in randomized and non-randomized designs. The Physiotherapy Evidence Database (PEDro) scale was used to assess the risk of bias. The random-effects model was used to compute the meta-analyses, reporting Hedges’ g effect sizes (ES) with 95% confidence intervals (95% CIs). Statistical significance was set at p ≤0.05. Subgroup analyses were performed (chronological age; PJT duration, frequency, number of sessions, total number of jumps; randomization). A meta-regression was conducted to verify if PJT frequency, duration, and total number of sessions predicted the effects of PJT on the RSI. Certainty or confidence in the body of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Potential adverse health effects derived from PJT were researched and reported. Results: Sixty-one articles were meta-analysed, with a median PEDro score of 6.0, a low risk of bias and good methodological quality, comprising 2,576 participants with an age range of 8.1 to 73.1 years (males, ~78%; aged under 18 years, ~60%), 42 studies included participants with a sport background (e.g., soccer, runners). The PJT duration ranged from 4 to 96 weeks, with 1-3 weekly exercise sessions. The RSI testing protocols involved the use of contact mats (n=42) and force platforms (n=19). Most studies reported RSI as mm/ms (n=25 studies) from drop jump analysis (n=47 studies). In general, PJT groups improved RSI compared to controls: ES= 0.54, CI= 0.46-0.62, p< 0.001. Training-induced RSI changes were greater (p= 0.023) for adults (i.e., age ≥18 years [group mean]) compared with youth. PJT was more effective with a duration of >7 weeks vs. ≤7 weeks, >14 total PJT sessions vs. ≤14 sessions, 3 weekly sessions vs. <3 sessions (p= 0.027 – 0.060). Similar RSI improvements were noted after ≤1,080 vs. >1,080 total jumps, and for non-randomized vs. randomized studies. Heterogeneity (I2) was low (0.0-22.2%) in nine analyses and moderate in three analyses (29.1-58.1%). According to the meta-regression, none of the analysed training variables explained the effects of PJT on RSI (p=0.714-0.984, R2 = 0.0). The certainty of the evidence was moderate for the main analysis, and low-to-moderate across the moderator analyses. Most studies did not report soreness, pain, injury, or related adverse effects related to PJT. Conclusions: The effects of PJT on the RSI were greater compared with active/specific-active controls, including traditional sport-specific training as well as alternative training interventions (e.g., high-load slow-speed resistance training). This conclusion is derived from 61 articles with low risk of bias (good methodological quality), low heterogeneity, and moderate certainty of evidence, comprising 2,576 participants. PJT-related improvements on RSI were greater for adults vs. youths, after >7 training weeks vs. ≤7 weeks, with >14 total PJT vs. ≤14 sessions, and with 3 vs. <3 weekly sessions.
... Physical inactivity is a consistent part of many people's daily life [1], as well as the possibility for prolonged phases of immobilization [2][3][4], which can have significant negative influences on metabolic and musculoskeletal health [5,6] in sports performance. In addition to injuries and frequent sitting, evidence highlights significantly decreased physical activity and motivation to train [7] in the majority of people due to the COVID-19 lockdown(s) [8][9][10]. ...
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There are many reasons for reduced physical activity leading to reduced maximal strength and sport-specific performance, such as jumping performance. These include pandemic lockdowns, serious injury, or prolonged sitting in daily work life. Consequently, such circumstances can contribute to increased morbidity and reduced physical performance. Therefore, a demand for space-saving and home-based training routines to counteract decreases in physical performance is suggested in the literature. This study aimed to investigate the possibility of using daily static stretching using a stretching board to counteract inactivity-related decreases in performance. Thirty-five (35) participants were either allocated to an intervention group (IG), performing a daily ten-minute stretch training combined with reduced physical activity or a reduced physical activity-only group (rPA). The effects on maximal voluntary contraction, range of motion using the knee-to-wall test, countermovement jump height (CMJheight), squat jump height (SJheight), drop jump height (DJheight), contact time (DJct) and the reactive strength index (DJRSI) were evaluated using a pre-test-post-test design. The rPA group reported reduced physical activity because of lockdown. Results showed significant decreases in flexibility and jump performance (d = −0.11–−0.36, p = 0.004–0.046) within the six weeks intervention period with the rPA group. In contrast, the IG showed significant increases in MVC90 (d = 0.3, p < 0.001) and ROM (d = 0.44, p < 0.001) with significant improvements in SJheight (d = 0.14, p = 0.002), while no change was measured for CMJheight and DJ performance. Hence, 10 min of daily stretching seems to be sufficient to counteract inactivity-related performance decreases in young and healthy participants.
... This may influence the rehabilitation programme (e.g., duration, frequency, volume, intensity), and individual prescriptions are required to achieve the targeted strength gains. 18,25 Furthermore, pain interference might reduce maximal voluntary contraction, [26][27][28] and thus should be reported and taken into consideration when interpreting the results. 26,29,30 Thus, the aim of this systematic review was to investigate whether people with musculoskeletal pain show differences in global measures of strength in comparison to healthy cohorts. ...
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Objective It is currently unknown if people with musculoskeletal pain display different multi-joint strength capacities than healthy cohorts. The aim was to investigate whether people with musculoskeletal pain show differences in global measures of strength in comparison to healthy cohorts. Data sources A systematic review was conducted using three databases (Medline, CINAHL and SPORTDiscus) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Review methods Studies involving participants with painful musculoskeletal conditions and multi-joint strength assessment measured at baseline were included. A meta-analysis was also performed to compute standardized mean differences (± 95% confidence intervals), using Hedge's g, and examined the differences in multi-joint strength at baseline between participants with painful musculoskeletal conditions and healthy participants. Results In total, 5043 articles were identified, of which 20 articles met the inclusion criteria and were included in the qualitative analysis. The available evidence revealed that multi-joint strength values were limited to knee osteoarthritis, fibromyalgia, chronic low back pain, and rheumatoid arthritis. Only four studies were included in the quantitative synthesis and revealed that only small differences in both chest press ( g = −0.34, 95% CI [−0.64, −0.03]) and leg press ( g = −0.25, 95% CI [−0.49, −0.02]) existed between adult women with fibromyalgia and active community women. Conclusion There is a paucity of multi-joint strength values in participants with musculoskeletal pain. Quantitative comparison with healthy cohorts was limited, except for those with fibromyalgia. Adult women with fibromyalgia displayed reduced multi-joint strength values in comparison to active community women.
... Complex training can also be incorporated into rehabilitation, as the inherent load manipulation (targeting specific force or velocity components of the force-velocity relationship) allows practitioners to adjust many variables that can aid in return to training and performance (e.g., inclusion of plyometrics in terminal phase of rehabilitation) [116,117]. Finally, and most importantly when considering how to implement these methods into a training plan, the purpose of the training is paramount rather than focusing solely on the groupings of exercises, as each will have its own adaptive response and the underpinning rationale of implementation may differ depending on contextual factors. ...
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The primary aim of this narrative review was to outline the historical genesis of resistance training strategies that incorporate high-load, low-velocity exercises and low-load, high-velocity exercises in the same training session allowing for different "exercise sequences" to be simultaneously implemented. Discrepancies between scientific works and the terminology used within contemporary sport science publications are identified. Upon review of the literature, we propose "complex training" to be considered an umbrella term with 4 different implementations, generally used to indicate a method in which movement velocity or load is altered between sets and/or exercises within the same session with the aim of improving slow and fast force expression. We propose the following terminology for said implementations: contrast training-exercise sequence with alternating high-load and low-load (higher-velocity) exercises in a set-by-set fashion within the same session (corresponding with 'intra-contrast pairs' and 'intra-contrast rest'); descending training-several sets of high-load (e.g., back squat) exercises completed before the execution of several sets of low-load, higher-velocity (e.g., vertical jump) exercises within the same session; ascending training-several sets of low-load, higher-velocity exercises completed before several sets of high-load exercises within the same session; and French contrast training-subset of contrast training in which a series of exercises are performed in sequence within a single session: heavy compound exercise, plyometric exercise, light-to-moderate load compound exercise that maximizes movement speed (i.e., external power), and a plyometric exercise (often assisted). Finally, practical applications and training considerations are presented.
... N respectively), there are hardly any variations in the inter-articular ratio (ER:IR = 0.65 dominant arm vs. 0.67 non-dominant arm) [17]. Despite all this, imbalances in force production are synonymous with a greater probability of suffering an injury [18]. ...
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Background: Water-polo is the water sport with the highest incidence of injuries, with shoulder pain being the most common one. The understanding of risk factors and guidance on preventive measures is essential in this sport discipline. The aim of this study was to determine the effects of a specific 6-week training plan on range of motion (ROM) and joint strength levels in a group of professional water-polo players. Methods: Quasi-experimental study with a sample of 28 participants (age: 20.1 ± 2.5 years; height: 176.9 ± 6.2 cm; body mass: 74.6 ± 8.1 kg). Three study groups, which consisted of one control group and two experimental groups, were established. Two repeated measurements, pre and post intervention, were performed. During these measurements, ROM of the glenohumeral joint was analyzed both in external (ER) and internal (IR) rotation, as well as the maximal isometric strength. Conclusions: The application of a training program improved glenohumeral joint ROM. ER and IR evolve differently in both shoulders. ER improved only in the throwing arm only in the group undergoing intervention but for the non-dominant side, improvements were observed in both ER and IR, regardless of whether or not they had followed the intervention plan. No improvements were observed in either the isometric strength or contralateral asymmetries.
Isometrisches Training wird seit ein paar Jahren zur Schmerzlinderung bei einer Achillessehnentendinopathie empfohlen. Doch nicht nur Schmerz, auch die reduzierte physische Leistungsfähigkeit sollte in der Therapie adressiert werden, da diese möglicherweise zu Rückfällen führen kann. Kann Isometrie auch die Leistungsfähigkeit beeinflussen?
Purpose: Power training (PT) is a promising training modality to improve functional abilities in children with cerebral palsy (CP). This study aimed to implement PT in an adapted school and to assess its effect on locomotion capacities in children with Gross Motor Function Classification System (GMFCS) level III-IV. Materials and methods: Nine children with CP (GMFCS level III-IV) were trained three times/week for 12 weeks. The training sessions took place during the 50-minute physical activity classes and included high intensity exercise. The outcome measures were the performance on the 10-meter comfortable and fast walking tests, the 50-meter sprint test (50M-ST), and the energy expenditure index (EEI). Results: Participants spent 12 ± 7 and 7 ± 9 min per session at an intensity superior to 40% and 60% of the heart rate reserve, respectively. Performance in the 10-meter walking test (13.5 ± 7.8 to 9.9 ± 4.6 s, p < 0.05), the 10-meter fast walking test (8.8 ± 3.1 to 7.0 ± 3.2 s, p < 0.05), the 6-minute walking exercise (199.0 ± 48.6 to 316.6 ± 107.2 m, p < 0.05), and in 50M-ST (53.8 ± 29.5 to 42.3 ± 16.2 s, p < 0.05) increased after training. The EEI was reduced after training (p = 0.01), resulting in a more efficient gait. Conclusions: PT was successfully implemented in children with CP with GMFCS level III-IV. Results suggest that PT increases walking capacities.Implications for rehabilitationPower training (PT) is feasible with children with bilateral cerebral palsy with GMFCS level III and IV.Physical education course in specialist school is a valuable environment to implement PT in children with poor gross motor function.Power training results in locomotion capacities improvement.
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The subject of study on which this work focuses is related to high-performance track and field, specifically sprinting. The aim is to analyse a weakness in the entity where the university internships have been carried out in order to be able to implement proposals for improvement that optimise, in this case, sport performance. To do this, a group of sprint training belonging to the Club Escuela Atletismo Majadahonda were analysed, using various techniques such as direct observation, monitoring of training sessions or informal conversations with the coach and athletes. The main weakness observed was a high training load in the form of plyometric and strength work, of which the magnitude of metabolic and mechanical stress they can cause is unknown. These aspects are of great interest, as the existence of a relationship between jumping capacity, strength production and performance in high-intensity sprints is being considered. In order to establish a proposal for improvement, a broad theoretical framework will be described in which the determining aspects of the training process on sprinting performance will be presented. Finally, a series of practical tests with their respective technological tools are presented. In addition, recommendations are established in terms of the periodisation of the tests, the programming of the protocol and of these tests throughout the season. Once the effects of the training load are known with greater accuracy, a strength training programming proposal is described, prioritising certain exercises with a greater transfer to sprint performance. By way of conclusion, we reflect on the traditional training programmes with high fatiguing volumes, dismantling this old conception through evidence of the same effects with a reduction in training.
The cause of injury is often multifactorial and rarely the preserve of one independent factor. Inconsistency in the use of injury terminology, data collection procedures, calculation of exposure, and operational measures of performance by researchers exist. Standardising the criteria used to attribute injury and climbing activity, coupled with more accurate methods of calculating exposure, will overcome such limitations.Injury prevention in sport should therefore be governed by logical principles that provide the athlete, healthcare professional and coaching team with direction. In the sport of climbing, athletes need to be physically prepared to fully meet the demands imposed upon them. Athletic development and physical preparation strategies are a cornerstone of climbing performance and injury prevention. The ability of musculoskeletal tissues to adapt its material, morphological and physiological properties provide a performance advantage. Although there is a paucity of empirical research evidence in climbing populations, the use of injury surveillance, work load monitoring protocols, and physical preparation strategies may facilitate better future injury prevention planning.KeywordsWorkload monitoringInjury surveillanceAthletic developmentPhysical preparation
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Isometric training is used in the rehabilitation and physical preparation of athletes, special populations and the general public. However, little consensus exists regarding training guidelines for a variety of desired outcomes. Understanding the adaptive response to specific loading parameters would be of benefit to practitioners. The objective of this systematic review, therefore, was to detail the medium to long‐term adaptations of different types of isometric training on morphological, neurological and performance variables. Exploration of the relevant subject matter was performed through MEDLINE, PubMed, SPORTDiscus and CINAHL databases. English, full‐text, peer‐reviewed journal articles and unpublished doctoral dissertations investigating medium to long‐term (≥3 weeks) adaptations to isometric training in humans were identified. These studies were evaluated further for methodological quality. Twenty‐six research outputs were reviewed. Isometric training at longer muscle lengths (0.86‐1.69%/week, ES = 0.03‐0.09/week) produced greater muscular hypertrophy when compared to equal volumes of shorter muscle length training (0.08‐0.83%/week, ES = ‐0.003‐0.07/week). Ballistic intent resulted in greater neuromuscular activation (1.04‐10.5%/week, ES = 0.02‐0.31/week vs. 1.64‐5.53%/week, ES = 0.03‐0.20/week) and rapid force production (1.2‐13.4%/week, ES = 0.05‐0.61/week vs. 1.01‐8.13%/week, ES = 0.06‐0.22/week). Substantial improvements in muscular hypertrophy and maximal force production were reported regardless of training intensity. High‐intensity (≥ 70%) contractions are required for improving tendon structure and function. Additionally, long muscle length training results in greater transference to dynamic performance. Despite relatively few studies meeting the inclusion criteria, this review provides practitioners with insight into which isometric training variables (e.g. joint angle, intensity, intent) to manipulate to achieve desired morphological and neuromuscular adaptations.
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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-thigh pulls and countermovement jumps to permit the calculation of DSI. T-tests and Cohen’s effect sizes revealed a significant but small (p = 0.009, d = 0.50) decrease in DSI post-training (0.71 ± 0.13 N·N−1) compared to pre-training (0.65 ± 0.11 N·N−1); however, when divided into high and low DSI groups, differential responses were clear. The low DSI group exhibited no significant or meaningful (p = 1.000, d = 0.00) change in DSI pre to post-training (0.56 ± 0.05 N·N−1, 0.56 ± 0.09 N·N−1, respectively), whereas the high DSI group demonstrated a significant and large decrease (p = 0.034, d = 1.29) in DSI pre to post-training (0.85 ± 0.05 N·N−1, 0.74 ± 0.11 N·N−1, respectively), resulting in a significant and moderate difference (p = 0.034, d = 1.29) in the change in DSI between groups. These results demonstrate that DSI decreases in response to strength training, as expected, due to an increase in isometric mid-thigh pull peak force, with minimal change in dynamic (countermovement jump) peak force.
Objectives: To determine eccentric knee flexor strength in elite female Australian Rules Football (ARF) players with and without a history of unilateral anterior cruciate ligament reconstruction (ACLR) using an ipsilateral semitendinosus graft. Design: Case-control. Setting: Elite ARF Women's competition. Participants: Eighty-four elite female ARF players (mean age, 25 ± 4.9 years; height, 1.71 ± 0.73 m; weight, 67 kg ± 7.4 kg) with (n = 12) and without (n = 72) a history of unilateral ACLR in the previous 10 years. Main outcome measures: Peak eccentric knee flexor force during the Nordic hamstring exercise (NHE). Results: Players with a history of unilateral ACLR displayed lower levels of eccentric knee flexor strength in their surgically reconstructed limb than their uninjured contralateral limb (mean difference -53.77 N, 95% CI = -85.06 to -24.27, d = -0.51) and compared to the limbs of players with no history of injury (mean difference = -46.32 N, 95% CI = -86.65 to -11.13, d = -0.73). Conclusion: Elite female ARF players with a history of unilateral ACLR display deficits in eccentric knee flexor strength in their surgically reconstructed limb for up to 10 years following surgery.
Objectives: Determine how the strength and endurance of the plantar flexors are affected by Achilles tendinopathy and whether one muscle is more affected than another. Design: Case control study. Setting: University Laboratory. Participants: 39 Runners with mid-portion Achilles tendinopathy and 38 healthy runners participated in this study. Main outcome measures: Isokinetic dynamometry was completed bilaterally in two knee positions on all subjects to assess the torque and endurance capacity of the plantar flexors. Results: Subjects with Achilles tendinopathy were statistically weaker (by 26.1Nm Concentric 90°/sec, 14,8Nm Concentric 225°/sec and 55.5Nm Eccentric 90°/sec for knee extended testing and 17.3Nm, 10.1Nm and 52.3Nm for the flexed knee respectively) than healthy controls at all isokinetic test speeds and contraction modes irrespective of knee position (p value = <0.001). The endurance capacity of the plantar flexors was significantly reduced (Total work done 613.5Nm less) in subjects with Achilles tendinopathy when compared to the healthy controls (p value = <0.001). Conclusions: Achilles tendinopathy is associated with large deficits in plantar flexor torque and endurance. The deficits are bilateral in nature and appear to be explained by a greater loss of the soleus force generating capacity rather than the gastrocnemius.
Objective To describe the criteria used to clear athletes to return to sport (RTS) following primary ACL reconstruction. Design Scoping review. Data sources MEDLINE, Embase, CINAHL and SPORTDiscus electronic databases were searched using keywords related to ACL and RTS. Eligibility criteria Prospective or retrospective studies reporting at least one RTS criterion for athletes who had primary ACL reconstruction with an autograft. Results In total, 209 studies fulfilled the inclusion criteria. RTS criteria were categorised into six domains: time, strength, hop testing, clinical examination, patient-report and performance-based criteria. From the 209 included studies, time was used in 178 studies (85%), and in 88 studies (42%) was the sole RTS criterion. Strength tests were reported in 86 studies (41%). Sixteen different hop tests were used in 31 studies (15%). Clinical examination was used in 54 studies (26%), patient report in 26 studies (12%) and performance-based criteria in 41 studies (20%). Summary Time and impairment-based measures dominated RTS criteria, despite sport being a complex physical and biopsychosocial activity with demands across all aspects of function. Time was included as a criterion in 85% of studies, and over 80% of studies allowed RTS before 9 months. Whether RTS tests are valid—do they predict successful RTS?—is largely unknown.
Training frequency is considered an important variable in the hypertrophic response to regimented resistance exercise. The purpose of this paper was to conduct a systematic review and meta-analysis of experimental studies designed to investigate the effects of weekly training frequency on hypertrophic adaptations. Following a systematic search of PubMed/MEDLINE, Scoups, and SPORTDiscus databases, a total of 25 studies were deemed to meet inclusion criteria. Results showed no significant difference between higher and lower frequency on a volume-equated basis. Moreover, no significant differences were seen between frequencies of training across all categories when taking into account direct measures of growth, in those considered resistance-trained, and when segmenting into training for the upper body and lower body. Meta-regression analysis of non-volume-equated studies showed a significant effect favoring higher frequencies, although the overall difference in magnitude of effect between frequencies of 1 and 3+ days per week was modest. In conclusion, there is strong evidence that resistance training frequency does not significantly or meaningfully impact muscle hypertrophy when volume is equated. Thus, for a given training volume, individuals can choose a weekly frequency per muscle groups based on personal preference.
Background Patellofemoral pain (PFP) is a prevalent condition commencing at various points throughout life. We aimed to provide an evidence synthesis concerning predictive variables for PFP, to aid development of preventative interventions. Methods We searched Medline, Web of Science and SCOPUS until February 2017 for prospective studies investigating at least one potential risk factor for future PFP. Two independent reviewers appraised methodological quality using the Newcastle–Ottawa Scale. We conducted meta-analysis where appropriate, with standardised mean differences (SMD) and risk ratios calculated for continuous and nominal scaled data. Results This review included 18 studies involving 4818 participants, of whom 483 developed PFP (heterogeneous incidence 10%). Three distinct subgroups (military recruits, adolescents and recreational runners) were identified. Strong to moderate evidence indicated that age, height, weight, body mass index (BMI), body fat and Q angle were not risk factors for future PFP. Moderate evidence indicated that quadriceps weakness was a risk factor for future PFP in the military, especially when normalised by BMI (SMD −0.69, CI −1.02, –0.35). Moderate evidence indicated that hip weakness was not a risk factor for future PFP (multiple pooled SMDs, range −0.09 to −0.20), but in adolescents, moderate evidence indicated that increased hip abduction strength was a risk factor for future PFP (SMD 0.71, CI 0.39, 1.04). Conclusions This review identified multiple variables that did not predict future PFP, but quadriceps weakness in military recruits and higher hip strength in adolescents were risk factors for PFP. Identifying modifiable risk factors is an urgent priority to improve prevention and treatment outcomes.
Isometric exercise is commonly recommended for immediate pain relief in individuals suffering from lower limb tendinopathies, despite the limited evidence supporting its analgesic effect. Due to the similarities between plantar fasciopathy and tendinopathies, the aim of this trial was to investigate the acute effect of isometric exercise on pain, compared to isotonic exercise, or walking, in individuals with plantar fasciopathy. We recruited 20 individuals with plantar fasciopathy for this prospectively‐registered, participant‐blinded, randomised, superiority crossover trial (ClinicalTrials. gov: NCT03264729). Participants attended three exercise sessions (isometric, isotonic or walking) in a randomised order, within a two‐week period. Both isometric and isotonic exercises were performed standing with the forefoot on a step bench, while walking was performed barefoot. The primary outcome was pain (measured on a 0‐100mm VAS) during a pain‐aggravating activity. Secondary outcomes included pressure pain threshold (PPT) under the heel, and plantar fascia thickness (PFT). All outcomes were measured before and after each exercise session. There were no significant differences between the three exercises on pain (P=0.753), PPTs (P=0.837) or PFT (P=0.718). Further, there was no change in pain from before to after any of the exercises (isometric exercise 2.7mm (95%CI: ‐12.2; 6.8), isotonic exercise ‐3.4mm (95%CI: ‐5.0; 11.8) or walking 1.6mm (95%CI: ‐16.1; 12.9)). Contrary to expectations, isometric exercise was no better than isotonic exercise or walking at reducing pain in individuals with plantar fasciopathy. None of the exercises induced any systematic analgesic effect. This article is protected by copyright. All rights reserved.