Sessional work-rate does not affect the magnitude to which simulated hypoxia can augment acute physiological responses during resistance exercise.

PURPOSE: To investigate whether performing resistance exercise in hypoxia augments physiological and perceptual responses, and if altering work-rate by performing repetitions to failure compared to sub-maximally increases the magnitude of these responses. METHODS: Twenty male university students (minimum of 2 year resistance training experience) completed four sessions, two in hypoxia (fraction of inspired oxygen [FiO2] = 0.13), and two in normoxia (FiO2 = 0.21). For each condition, session one comprised three sets to failure of shoulder press and bench press (high work-rate session), while session two involved the same volume load, distributed over six sets (low work-rate session). Muscle oxygenation (triceps brachii), surface electromyographic activity (anterior deltoid, pectoralis major, and triceps brachii), heart rate (HR), and arterial blood oxygen saturation were recorded. Blood lactate concentration ([Bla-]) was recorded pre-exercise and 2 min after each exercise. Muscle thickness was measured pre- and post-exercise via ultrasound. RESULTS: Muscle oxygenation values during sets and inter-set rest periods were lower in hypoxia vs normoxia (p = 0.001). Hypoxia caused greater [Bla-] during the shoulder press of failure sessions (p = 0.003) and both shoulder press (p = 0.048) and bench press (p = 0.005) of non-failure sessions. Hypoxia increased HR during non-failure sessions (p < 0.001). There was no effect of hypoxia on muscular swelling, surface electromyographic activity, perceived exertion, or number of repetitions performed. CONCLUSIONS: Hypoxia augmented metabolite accumulation, but had no impact on any other physiological or perceptual response compared to the equivalent exercise in normoxia. Furthermore, the magnitude to which hypoxia increased the measured physiological responses was not influenced by sessional work-rate.

Using a Load-Velocity Relationship to Predict One repetition maximum in Free-Weight Exercise: A Comparison of the Different Methods.

Hughes, LJ, Banyard, HG, Dempsey, AR, and Scott, BR. Using a load-velocity relationship to predict one repetition maximum in free-weight exercise: a comparison of the different methods. J Strength Cond Res 33(9): 2409-2419, 2019-The purpose of this study was to investigate the reliability and validity of predicting 1 repetition maximum (1RM) in trained individuals using a load-velocity relationship. Twenty strength-trained men (age: 24.3 ± 2.9 years, height: 180.1 ± 5.9 cm, and body mass: 84.2 ± 10.5 kg) were recruited and visited the laboratory on 3 occasions. The load-velocity relationship was developed using the mean concentric velocity of repetitions performed at loads between 20 and 90% 1RM. Predicted 1RM was calculated using 3 different methods discussed in existing research: minimal velocity threshold 1RM (1RMMVT), load at zero velocity 1RM (1RMLD0), and force-velocity 1RM methods (1RMFV). The reliability of 1RM predictions was examined using intraclass correlation coefficient (ICC) and coefficient of variation (CV). 1RMMVT demonstrated the highest reliability (ICC = 0.92-0.96, CV = 3.6-5.0%), followed by 1RMLD0 (ICC = 0.78-0.82, CV = 8.2-8.6%) and 1RMFV (ICC = -0.28 to 0.00, CV = N/A). Both 1RMMVT and 1RMLD0 were very strongly correlated with measured 1RM (r = 0.91-0.95). The only method which was not significantly different to measured 1RM was the 1RMLD0 method. However, when analyzed on an individual basis (using Bland-Altman plots), all methods exhibited a high degree of variability. Overall, the results suggest that the 1RMMVT and 1RMLD0 predicted 1RM values could be used to monitor strength progress in trained individuals without the need for maximal testing. However, given the significant differences between 1RMMVT and measured 1RM, and the high variability associated with individual predictions performed using each method, they cannot be used interchangeably; therefore, it is recommended that predicted 1RM is not used to prescribe training loads as has been previously suggested.

Using Load-Velocity Relationships to Quantify Training-Induced Fatigue.

Hughes, LJ, Banyard, HG, Dempsey, AR, Peiffer, JJ, and Scott, BR. Using load-velocity relationships to quantify training-induced fatigue. J Strength Cond Res 33(3): 762-773, 2019-The purpose of this study was to investigate using load-velocity relationships to quantify fluctuations in maximal strength (1 repetition maximum [1RM]), which occur as a result of training-induced fatigue. The 19 well-trained men (age: 24.3 ± 2.9 years, height: 180.1 ± 5.9 cm, body mass: 84.2 ± 10.5 kg, and squat 1RM: 151.1 ± 25.7 kg) who were recruited for this study attended 5 sessions. After baseline strength testing, individual load-velocity relationships were established using mean concentric velocity during visits 2, 4, and 5, with visit 3 consisting of a bout of fatiguing exercise (5 sets of squats performed to muscular failure with 70% 1RM). Predicted 1RM values were calculated using the minimal velocity threshold (1RMMVT), load at zero velocity (1RMLD0), and force-velocity (1RMFV) methods. Measured 1RM, maximal voluntary contractions, and perceived muscle soreness were used to examine the effects of fatigue in relation to the predicted 1RM scores. The 1RMMVT and 1RMLD0 demonstrated very strong and strong correlations with measured 1RM during each of the sessions (r = 0.90-0.96 and r = 0.77-0.84, respectively), while no strong significant correlations were observed for the 1RMFV. Further analysis using Bland-Altman plots demonstrated substantial interindividual variation associated with each method. These results suggest that load-velocity-based 1RM predictions are not accurate enough to be used for daily training load prescription, as has been previously suggested. Nevertheless, these predictions are practical to implement during an individual's warm-up and may be useful to indicate general fluctuations in performance potential, particularly if used in conjunction with other common monitoring methods.

Cartilage morphology at 2-3 years following anterior cruciate ligament reconstruction with or without concomitant meniscal pathology.

PURPOSE: To examine differences in cartilage morphology between young adults 2-3 years post-anterior cruciate ligament reconstruction (ACLR), with or without meniscal pathology, and control participants. METHODS: Knee MRI was performed on 130 participants aged 18-40 years (62 with isolated ACLR, 38 with combined ACLR and meniscal pathology, and 30 healthy controls). Cartilage defects, cartilage volume and bone marrow lesions (BMLs) were assessed from MRI using validated methods. RESULTS: Cartilage defects were more prevalent in the isolated ACLR (69 %) and combined group (84 %) than in controls (10 %, P < 0.001). Furthermore, the combined group showed higher prevalence of cartilage defects on medial femoral condyle (OR 4.7, 95 % CI 1.3-16.6) and patella (OR 7.8, 95 % CI 1.5-40.7) than the isolated ACLR group. Cartilage volume was lower in both ACLR groups compared with controls (medial tibia, lateral tibia and patella, P < 0.05), whilst prevalence of BMLs was higher on lateral tibia (P < 0.001), with no significant differences between the two ACLR groups for either measure. CONCLUSIONS: Cartilage morphology was worse in ACLR patients compared with healthy controls. ACLR patients with associated meniscal pathology have a higher prevalence of cartilage defects than ACLR patients without meniscal pathology. The findings suggest that concomitant meniscal pathology may lead to a greater risk of future OA than isolated ACLR. LEVEL OF EVIDENCE: III.

Glucose Ingestion Does Not Improve Maximal Isokinetic Force.

The purpose of this study was to assess maximal isokinetic leg extension force in response to glucose ingestion and to determine whether any performance changes occur in a time-dependent manner. Seventeen young (22.1 ± 3.9 years), lean (%body fat [%BF]: 14.3 ± 8.0; %BF males: 9.7 ± 4.2; %BF females: 23.7 ± 4.2), and recreationally active (>150 min · wk(-1) of physical activity) male (n = 11) and female participants completed the trials. Using a double-blinded crossover design, participants performed sets of 3 maximum isokinetic efforts on a dynamometer (HumacNorm) before and after (5, 15, 30, 45, 60, 75, and 90 minutes after) ingesting either a carbohydrate (75 g glucose) or isovolumic placebo (saccharin-flavored) drink. Blood glucose and electromyography (EMG) were recorded concurrent with force output (max peak force; mean peak force). Despite a significant rise in blood glucose (mean glycemic excursion = 4.01 ± 1.18 mmol · L(-1)), there were no significant interactions in any (absolute or percentage) force (mean peak force: p ≥ 0.683; max peak force: p ≥ 0.567) or EMG (mean peak EMG: p ≥ 0.119; max peak EMG: p ≥ 0.247) parameters measured. The ingestion of glucose resulted in a 3.4% reduction in mean force across subsequent time points (highest: +2.1% at 15 minutes; lowest: -8.6% at 90 minutes after ingestion); however, this effect was small (d < 0.1). The ingestion of glucose does not alter performance of maximal isokinetic efforts in recreationally active young individuals. Additionally, there were no differences in force when assessed as a function of time after glucose ingestion. Consequently, in the absence of fatigue, carbohydrate ingestion is unlikely to present any ergogenic benefits to athletes performing resistance-based exercise.

Comparing the Effectiveness of a Short-Term Vertical Jump vs. Weightlifting Program on Athletic Power Development.

Teo, SYM, Newton, MJ, Newton, RU, Dempsey, AR, and Fairchild, TJ. Comparing the effectiveness of a short-term vertical jump vs. weightlifting program on athletic power development. J Strength Cond Res 30(10): 2741-2748, 2016-Efficient training of neuromuscular power and the translation of this power to sport-specific tasks is a key objective in the preparation of athletes involved in team-based sports. The purpose of this study was to compare changes in center of mass (COM) neuromuscular power and performance of sport-specific tasks after short-term (6-week) training adopting either Olympic-style weightlifting (WL) exercises or vertical jump (VJ) exercises. Twenty-six recreationally active men (18-30 years; height: 178.7 ± 8.3 cm; mass: 78.6 ± 12.2 kg) were randomly allocated to either a WL or VJ training group and performance during the countermovement jump (CMJ), squat jump (SJ), depth jump (DJ), 20-m sprint, and the 5-0-5 agility test-assessed pre and posttraining. Despite the WL group demonstrating larger increases in peak power output during the CMJ (WL group: 10% increase, d = 0.701; VJ group: 5.78% increase, d = 0.328) and SJ (WL group: 12.73% increase, d = 0.854; VJ group: 7.27% increase, d = 0.382), no significant between-group differences were observed in any outcome measure studied. There was a significant main effect of time observed for the 3 VJs (CMJ, SJ, and DJ), 0- to 5-m and 0- to 20-m sprint times, and the 5-0-5 agility test time, which were all shown to improve after the training (all main effects of time p < 0.01). Irrespective of the training approach adopted by coaches or athletes, addition of either WL or VJ training for development of power can improve performance in tasks associated with team-based sports, even in athletes with limited preseason training periods.

Morphology versus function: the relationship between lumbar multifidus intramuscular adipose tissue and muscle function among patients with low back pain.

OBJECTIVE: To explore the bivariate and multivariate relations between fatty degeneration of the lumbar multifidus muscle (LMM) and LMM function among patients with low back pain (LBP). DESIGN: Cross-sectional clinical study. SETTING: Hospital. PARTICIPANTS: Patients with LBP (N=70) referred for lumbar spine magnetic resonance imaging. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: LMM morphology and function were measured at the L4/L5 and L5/S1 spinal levels bilaterally. Quantitative measures of LMM intramuscular adipose tissue (IMAT) were derived from T1-weighted magnetic resonance images. Function was assessed with ultrasound imaging by measuring change in LMM thickness during a submaximal contraction task. The study participants self-reported their level of LBP-related disability (Modified Oswestry Index), pain intensity (numerical pain rating scale), and physical activity (International Physical Activity Questionnaire). Bivariate and multivariate relations between LMM morphology and function were explored with correlational and hierarchical linear regression analyses, respectively. Additionally, we explored for possible covariates with potential to modify the relation between LMM IMAT and function. RESULTS: There were 70 participants (12 women) enrolled in the study (mean age, 45.4±11.9y). A high level of physical activity was reported by 45.5% of participates. Age, sex, and physical activity level demonstrated variable relations with LMM IMAT and LMM function. There were no significant bivariate or multivariate relations between LMM IMAT and LMM function. CONCLUSIONS: We observed higher levels of physical activity and LMM function and less LMM IMAT than previous studies involving patients with LBP. There was no relation between LMM morphology and function in this cohort of patients with LBP. Issues specific to LMM measurement and recommendations for future research are discussed.

Knee muscle strength after recent partial meniscectomy does not relate to 2-year change in knee adduction moment.

BACKGROUND: Knee muscle weakness and a greater external knee adduction moment are suggested risk factors for medial tibiofemoral knee osteoarthritis. Knee muscle weakness and a greater knee adduction moment may be related to each other, are potentially modifiable, and have been observed after arthroscopic partial meniscectomy. QUESTIONS/PURPOSES: The aim of this exploratory study was to determine if knee muscle weakness 3 months after arthroscopic partial meniscectomy (baseline) is associated with an increase in external knee adduction parameters during the subsequent 2 years. METHODS: Eighty-two participants undergoing medial arthroscopic partial meniscectomy were assessed at baseline, and 66 participants who were reassessed 2 years later were included in our study. Isokinetic muscle strength and external adduction moment parameters (peak and impulse) during normal and fast walking were measured at baseline and followup. Multiple linear regression models were used to examine the association between baseline muscle strength and 2-year change in adduction moment parameters. A post hoc power calculation showed we had 80% power to detect a correlation of 0.31 between baseline muscle strength and change in the external knee adduction, with an alpha error of 0.05 and two-sided significance. RESULTS: Maximal isokinetic muscle strength 3 months after arthroscopic partial meniscectomy was not associated with change in adduction moment parameters (p value range from 0.12 to 0.96). CONCLUSIONS: No evidence was found to suggest that improving maximal knee muscle strength after a recent arthroscopic partial meniscectomy would reduce change in knee adduction moment observed during the subsequent 2 years. As muscle function is modifiable, future investigation of other aspects of muscle function that may relate to change in knee adduction moment is warranted.

What do community football players think about different exercise-training programmes? Implications for the delivery of lower limb injury prevention programmes.

BACKGROUND: Players are the targeted end-users and beneficiaries of exercise-training programmes implemented during coach-led training sessions, and the success of programmes depends upon their active participation. Two variants of an exercise-training programme were incorporated into the regular training schedules of 40 community Australian Football teams, over two seasons. One variant replicated common training practices, while the second was an evidence-based programme to alter biomechanical and neuromuscular factors related to risk of knee injuries. This paper describes the structure of the implemented programmes and compares players' end-of-season views about the programme variants. METHODS: This study was nested within a larger group-clustered randomised controlled trial of the effectiveness of two exercise-training programmes (control and neuromuscular control (NMC)) for preventing knee injuries. A post-season self-report survey, derived from Health Belief Model constructs, included questions to obtain players' views about the benefits and physical challenges of the programme in which they participated. RESULTS: Compared with control players, those who participated in the NMC programme found it to be less physically challenging but more enjoyable and potentially of more benefit. Suggestions from players about potential improvements to the training programme and its future implementation included reducing duration, increasing range of drills/exercises and promoting its injury prevention and other benefits to players. CONCLUSIONS: Players provide valuable feedback about the content and focus of implemented exercise-training programmes, that will directly inform the delivery of similar, or more successful, programmes in the future.

Can technique modification training reduce knee moments in a landing task?

Anterior cruciate ligament (ACL) injuries are costly. Sidestep technique training reduces knee moments that load the ACL. This study examined whether landing technique training alters knee moments. Nineteen team sport athletes completed the study. Motion analysis and ground reaction forces were recorded before and after 6 weeks of technique modification. An inverse dynamic model was used to calculate three-dimensional knee loading. Pre- and postintervention scores were compared using paired t tests. Maximal knee flexion angle during landing was increased following training. There was no change in valgus or flexion moments, but an increase in peak internal rotation moment. This increase in internal rotation moment may increase the risk of ACL injury. However, the increased angle at which the peak internal rotation moment occurred at follow up may mitigate any increase in injury risk by reducing load transmission.

Pick-up of early visual information to guide kinetics and kinematics within a group of highly skilled baseball batters.

This pilot study integrated sport expertise and biomechanics methodologies within a baseball batting task. Purpose was to examine differences within a highly skilled group of baseball batters to use visual information to guide weight transfer and bat movements. One batter who played at Major League Baseball (MLB) level was compared to five batters who played at Australian Baseball League (ABL) level in a case-control design. Batters faced pitchers in a simulated competition and attempted to hit pitches, while vision was temporally occluded during ball flight or not occluded. Time of weight transfer (kinetics), as well as bat downswing initiation and duration (kinematics) from the point of ball release, were compared between the MLB batter and ABL batters. Results indicated that the MLB batter coordinated his striking pattern by completing his weight transfer earlier than the ABL batters. His bat downswing was also initiated earlier than some ABL batters, but there was no difference in duration of bat downswing between batters. All batters initiated bat downswing prior to completion of weight transfer. Understanding of motor expertise is furthered using a novel methodology.

Continuous blood flow restriction during repeated-sprint exercise increases peripheral but not systemic physiological and perceptual demands.

This study examined the impact of continuous blood flow restriction (BFR) during repeated-sprint exercise (RSE) on acute performance, peripheral, systemic physiological, and perceptual responses. In a randomized crossover design, 26 adult male semi-professional and amateur team-sport players completed two RSE sessions (3 sets of 5 × 5-s sprints with 25 s of passive recovery and 3 min of rest) with continuous BFR (45% arterial occlusion; excluding during between-set rest periods) or without (non-BFR). Mean and peak power output were significantly lower (p < 0.001) during BFR compared to non-BFR (dz = 0.85 and 0.77, respectively). Minimum tissue saturation index during the sprints and rest periods was significantly reduced (p < 0.001) for BFR (dz = 1.26 and 1.21, respectively). Electromyography root mean square was significantly decreased (p < 0.01) for biceps femoris and lateral gastrocnemius muscles during BFR (dz = 0.35 and 0.79, respectively), but remained unchanged for the vastus lateralis muscle in both conditions. Oxygen consumption and minute ventilation were significantly reduced (both p < 0.01) for BFR (dz = 1.46 and 0.43, respectively). Perceived limb discomfort was significantly higher (p < 0.001) for BFR (dz = 0.78). No differences (p > 0.05) in blood lactate concentration or rating of perceived exertion were observed between conditions. Blood flow-restricted RSE reduced performance and likely increased the physiological and perceptual stimulus for the periphery with greater reliance on anaerobic glycolysis, despite comparable or decreased systemic demands.

The relationship between patellofemoral and tibiofemoral morphology and gait biomechanics following arthroscopic partial medial meniscectomy.

PURPOSE: To examine the relationship between tibiofemoral and patellofemoral joint articular cartilage and subchondral bone in the medial and gait biomechanics following partial medial meniscectomy. METHODS: For this cross-sectional study, 122 patients aged 30-55 years, without evidence of knee osteoarthritis at arthroscopic partial medial meniscectomy, underwent gait analysis and MRI on the operated knee once for each sub-cohort of 3 months, 2 years, or 4 years post-surgery. Cartilage volume, cartilage defects, and bone size were assessed from the MRI using validated methods. The 1st peak in the knee adduction moment, knee adduction moment impulse, 1st peak in the knee flexion moment, knee extension range of motion, and the heel strike transient from the vertical ground reaction force trace were identified from the gait data. RESULTS: Increased knee stance phase range of motion was associated with decreased patella cartilage volume (B = -17.9 (95% CI -35.4, -0.4) p = 0.045) while knee adduction moment impulse was associated with increased medial tibial plateau area (B = 7.7 (95% CI 0.9, 13.3) p = 0.025). A number of other variables approached significance. CONCLUSIONS: Knee joint biomechanics exhibited by persons who had undergone arthroscopic partial meniscectomy gait may go some way to explaining the morphological degeneration observed at the patellofemoral and tibiofemoral compartments of the knee as patients progress from surgery. LEVEL OF EVIDENCE: III.

Blood flow restricted walking alters gait kinematics.

This study investigated the impact of blood flow restriction (BFR) during treadmill walking on gait kinematics. Twenty-one participants completed one familiarisation and four experimental sessions, including two walking speeds (moderate [5.0 ± 0.3km·h-1] and fast [6.4 ± 0.4km·h-1]) and two occlusion conditions (BFR [60% of arterial occlusion pressure] and unrestricted). For each exercise intensity, the BFR session was performed first. Participants were instructed to walk as long as possible, with sessions capped at 20 min. Unrestricted sessions were time-matched, and the order of exercise intensity was randomised. Kinematics were collected over 10s every minute using retro-reflective markers affixed to specific body landmarks. Ratings of perceived exertion and discomfort were collected every two minutes. Blood samples were collected from the fingertip pre-exercise and the finger and toe post-exercise, and were analysed for lactate, electrolytes, and markers of cell-membrane damage. During the BFR sessions the cuffs remained inflated while the blood samples were collected. Fast-walk BFR sessions exhibited higher anterior trunk flexion (p = 0.001) and knee flexion during stance (p = 0.001) compared to all other sessions. Step width was increased during BFR sessions (p = 0.001), but no difference in step length (p = 0.300) or cadence (p = 0.922) were observed. The time required to elicit change in anterior trunk flexion and plantar-flexion angle at toe-off was shorter during BFR sessions (p = 0.024). The BFR sessions elicited the highest ratings of perceived exertion and discomfort, as well as blood lactate concentration (p ≤ 0.001). Application of BFR during moderate and fast treadmill walking modifies gait kinematics and exacerbates exercise-related sensations as well as blood lactate concentration.

Applying blood flow restriction changes walking kinematics, causing an overall increase in anterior trunk flexion and knee flexion during stance while simultaneously reducing plantar-flexion angle at toe-off and ankle joint velocity.Applying blood flow restriction exacerbate exercise-related sensations of exertion and discomfort.Sample site does not influence the level of post-exercise blood lactate or markers of cell-membrane potential and damage.

Changes in knee joint biomechanics following balance and technique training and a season of Australian football.

PURPOSE: Determine if balance and technique training (BTT) implemented adjunct to normal Australian football (AF) training reduces external knee loading during sidestepping. Additionally, the authors determined if an athlete's knee joint kinematics and kinetics change over a season of AF. METHODOLOGY: Eight amateur-level AF clubs (n=1,001 males) volunteered to participate in either 28 weeks of BTT or a 'sham' training (ST) adjunct to their normal preseason and regular training. A subset of 34 athletes (BTT, n=20; ST, n=14) were recruited for biomechanical testing in weeks 1-7 and 18-25 of the 28-week training intervention. During biomechanical testing, participants completed a series running, preplanned (PpSS) and unplanned sidestepping (UnSS) tasks. A linear mixed model (α=0.05) was used to determine if knee kinematics and peak moments during PpSS and UnSS were influenced by BTT and/or a season of AF. RESULTS: Both training groups significantly (p=0.025) decreased their peak internal-rotation knee moments during PpSS, and significantly (p=0.022) increased their peak valgus knee moments during UnSS following their respective training interventions. CONCLUSIONS: BTT was not effective in changing an athlete's knee joint biomechanics during sidestepping when conducted in 'real-world' training environments. Following normal AF training, the players had different changes to their knee joint biomechanics during both preplanned and unplanned sidestepping. When performing an unplanned sidestepping task in the latter half of a playing season, athletes are at an increased risk of ACL injury. The authors therefore recommend both sidestepping tasks are performed during biomechanical testing when assessing the effectiveness of prophylactic training protocols.

Patellofemoral and tibiofemoral articular cartilage and subchondral bone health following arthroscopic partial medial meniscectomy.

PURPOSE: To examine articular cartilage and subchondral bone changes in tibiofemoral and patellofemoral joints following partial medial meniscectomy. METHODS: For this cross-sectional study, 158 patients aged 30-55 years, without evidence of knee osteoarthritis at arthroscopic partial medial meniscectomy (APMM), and 38 controls were recruited. MRI was performed once on the operated knee for each subcohort of 3 months, 2 or 4 years post-surgery, and the randomly assigned knee of the controls. Cartilage volume, cartilage defects, and bone size were assessed using validated methods. RESULTS: Compared with controls, APMM patients had more prevalent cartilage defects in medial tibiofemoral (OR = 3.17, 95%CI 1.24-8.11) and patellofemoral (OR = 13.76, 95%CI 1.52-124.80) compartments, and increased medial tibial plateau bone area (B = 143.8, 95%CI 57.4-230.2). Time from APMM was positively associated with cartilage defect prevalence in medial tibiofemoral (OR = 1.02, 95%CI 1.00-1.03) and patellofemoral (OR = 1.04, 95%CI 1.01-1.07) compartments, and medial tibial plateau area (B = 2.5, 95%CI 0.8-4.3), but negatively associated with lateral tibial cartilage volume (B = -4.9, 95%CI -8.4 to -1.5). The association of APMM and time from APMM with patellar cartilage defects was independent of tibial cartilage volume. CONCLUSIONS: Partial medial meniscectomy is associated with adverse effects on articular cartilage and subchondral bone, which are associated with subsequent osteoarthritis, in both tibiofemoral and patellofemoral compartments. LEVEL OF EVIDENCE: III.

Do Sideline Tests of Vestibular and Oculomotor Function Accurately Diagnose Sports-Related Concussion in Adults? A Systematic Review and Meta-analysis.

BACKGROUND: Sports-related concussion (SRC) assessment tools are primarily based on subjective assessments of somatic, cognitive, and psychosocial/emotional symptoms. SRC symptoms remain underreported, and objective measures of SRC impairments would be valuable to assist diagnosis. Measurable impairments to vestibular and oculomotor processing have been shown to occur after SRC and may provide valid objective assessments. PURPOSE: Determine the diagnostic accuracy of sideline tests of vestibular and oculomotor dysfunction to identify SRC in adults. STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: Electronic databases and gray literature were searched from inception until February 12, 2020. Physically active individuals (>16 years of age) who participated in sports were included. The reference standard for SRC was a combination of clinical signs and symptoms (eg, the Sport Concussion Assessment Tool [SCAT]), and index tests included any oculomotor assessment tool. The QUADAS tool was used to assess risk of bias, with the credibility of the evidence being rated according to GRADE. RESULTS: A total of 8 studies were included in this review. All included studies used the King-Devick test, with no other measures being identified. Meta-analysis was performed on 4 studies with a summary sensitivity and specificity of 0.77 and 0.82, respectively. The overall credibility of the evidence was rated as very low. CONCLUSION: Caution must be taken when interpreting these results given the very low credibility of the evidence, and the true summary sensitivity and specificity may substantially differ from the values calculated within this systematic review. Therefore, we recommend that clinicians using the King-Devick test to diagnose SRC in adults do so in conjunction with other tools such as the SCAT. PROSPERO REGISTRATION: CRD42018106632.

Modifying bowling kinematics in cricket pace bowlers with exercise-based injury prevention: A cluster-randomised controlled trial.

OBJECTIVES: Undesirable bowling kinematics can increase the risk of low back injury. This study investigated if an exercise-based injury prevention program (IPP) could modify bowling kinematics in community-level adolescent pace bowlers. DESIGN: Cluster-randomised controlled trial. METHODS: Pace bowlers from eight cricket organisations were cluster-randomised into an intervention or control group. At baseline and follow-up sessions biomechanical bowling data were collected. Between sessions, the intervention group completed an eight-week IPP while the control continued their normal cricket activity. Treatment effects (95% CI) were estimated with linear mixed models. RESULTS: There were significant treatment effects favouring the intervention group for shoulder counter-rotation (-3.8°; -7.2° to -0.3°) and lateral trunk flexion relative to the pelvis (-2.2°; -4.0° to -0.5°). Shoulder counter-rotation also increased in the control group by 2.2° (Cohen's d=0.22). There were no effects of the intervention on: lateral trunk flexion at front foot contact (FFC) (1.2°; -2.5° to 4.8°), lateral trunk flexion at ball release (BR) (-0.5°; -3.0° to 2.0°), pelvis rotation at FFC (0.9°; -4.0° to 2.2°), pelvis rotation at BR (-1.1°; -5.7° to 3.6°), front hip angle at FFC (1.6°; -3.6° to 6.7°), front hip angle at BR (-1.6°; -5.0° to 1.9°), front knee angle at FFC (-1.1°; -4.5° to 2.3°), front knee angle at BR (1.7°; -5.6° to 9.1°), or ball velocity (1.1kmh-1; -7.5kmh-1 to 9.7kmh-1). CONCLUSIONS: The IPP maintained shoulder counter-rotation and lateral trunk flexion relative to the pelvis in the intervention group and this could attenuate injury risk. No treatment effects were observed for lower-limb kinematics.

Exercise-based injury prevention for community-level adolescent cricket pace bowlers: A cluster-randomised controlled trial.

OBJECTIVES: To investigate if an exercise-based injury prevention program (IPP) can modify risk factors for injury in community-level adolescent cricket pace bowlers. DESIGN: Cluster-randomised controlled trial. METHODS: Eight cricket organisations (training two times per week and no previous involvement in a structured IPP) participated in this cluster-randomised trial. Participants were aged 14-17 years, injury free, and not currently performing a rehabilitation/exercise program. Cricket organisations (clusters) were block-randomised by computerised number generation into an intervention group (performed an eight-week IPP at training) or control group (continued their usual cricket activity). Participants were not blinded to group allocation. Strength, endurance, and neuromuscular control were assessed at baseline and follow-up. Treatment effects were estimated using linear mixed models. RESULTS: Sixty-five male adolescent pace bowlers (intervention n=32 and control n=33) were randomised. There were significant treatment effects favouring the intervention group for shoulder strength (90°/s) 0.05 (95% CI 0.02-0.09) Nm/kg, hamstring strength (60°/s) 0.32 (95% CI 0.13-0.50) Nm/kg, hip adductor strength dominant 0.40 (95% CI 0.26-0.55) Nm/kg and non-dominant 0.33 (95% CI 0.20-0.47) Nm/kg, SEBT reach distance dominant 3.80 (95% CI 1.63-6.04) percent of leg length (%LL) and non-dominant 3.60 (95% CI 1.43-5.78) %LL, and back endurance 20.4 (95% CI 4.80-36.0) seconds. No differences were observed for shoulder strength (180°/s) (p=0.09), hamstring strength (180°/s) (p=0.07), lumbopelvic stability (p=0.90), and single leg squat knee valgus angle (dominant p=0.06, non-dominant p=0.15). CONCLUSIONS: Exercise-based IPPs can modify risk factors for injury in community-level adolescent pace bowlers. Future research is needed to confirm if IPPs can also reduce injury risk in this population.

Predictors of clinical success with stabilization exercise are associated with lower levels of lumbar multifidus intramuscular adipose tissue in patients with low back pain.

Purpose: Investigate the construct validity of prognostic factors purported to predict clinical success with stabilization exercise for low back pain by exploring their associations with lumbar multifidus composition.Methods: Patients with low back pain were recruited from a hospital imaging department. The presence of fivepredictors (age <40 years, positive prone instability test, aberrant trunk flexion movements, straight leg raise range of motion >91°, spinal hypermobility) were identified by standardized physical examination. Predictors were grouped by total positive findings and status on a clinical prediction rule. The proportion of lower lumbar multifidus intramuscular adipose tissue was measured with 3.0 T magnetic resonance imaging. Univariate and multivariate associations were examined with linear regression and reported with standardized beta coefficients (ß) and 95% confidence intervals.Results: Data from 62 patients (11 female) with mean (SD) age of 45.2 (11.8) years were included. Total number of predictors (ß[95% CI] = -0.37[-0.61,-0.12]; R2 = 0.12), positive prediction rule status (ß[95% CI] = -0.57[-0.79,-0.35]; R2 = 0.30), and age <40 years were associated with lower intramuscular adipose tissue (ß[95% CI] = -0.55[-0.77,-0.33]; R2 = 0.27). No other individual factors were associated with lumbar multifidus intramuscular adipose tissue.Conclusions: These findings support the construct validity of the grouped prognostic criteria. Future research should examine the clinical utility of these criteria. Implications for RehabilitationLow back pain is the single largest cause of disability worldwide and exercise therapy is recommended by international low back pain treatment guidelines.Lower levels of lumbar multifidus intramuscular adipose tissue were associated with predictors of clinical success with stabilization exercise.Higher proportions of lumbar multifidus intramuscular adipose tissue may help identify patients who require longer duration exercise training, or those who are unlikely to respond to stabilization exercise.