Lower Limb Fatigue Asymmetry of Preferred and Non-Preferred Legs after a Repeated-Sprint Test in Football Players with Previous Hamstring Injury

Football is the most widely played sport in the world and is thus associated with the highest total number of injuries of all sports. 12% of all football injuries are to the hamstrings, as this muscle group is subjected to constant stress during training and match play performance (Ekstrand, Hägglund, Waldén, 2011; Woods, Hawkins, Maltby, Hulse, Thomas & Hodson, 2004). While the influence of limb dominance has been extensively examined as a risk factor for injury in upper limb-dominant sports (e.g. badminton, tennis and baseball), little research has focussed on the dominance in the lower limbs. Since almost all footballers show a limb preference for kicking, an example of limb dominance, it is possible to speculate that limb-specific injury rates will vary between preferred and non-preferred legs (Brophy, Silvers, Gonzales and Mandelbaum, 2010). Previous research has also shown that injury rates increase with the accumulation of fatigue, and that inter-limb force production variation increases as fatigue progresses. Thus, the possibility exists that increases in inter-limb force production variability after fatiguing exercise would increase injury risk in football players. The purpose of the present research, therefore, was to examine changes in muscle force production and fatigue between preferred and non-preferred legs in football players with and without a history of unilateral hamstring injury (in the preferred kicking leg). In the single leg vertical jump, peak jump force of the preferred leg in the injured group changed by -12% whilst force in the non-preferred leg changed by -5%. Force in the non-injured preferred leg changed by -6% and changed by -8% in the non-preferred leg. These results indicate a clear difference in fatigue response between groups, and that the inter-limb difference in force production is greater in the preferred leg of the injured group. Decline in hamstring torque in the preferred leg of the injured group changed by 98%, and the non-preferred leg changed by 67%. While in the non-injured group, decline in hamstring torque changed by 219% and 852% respectively. The greater changes observed in the non-injured group was due to minimal fatigue before the fatigue condition (repeated-sprint test). The injured group had a greater fatigue response both before and after the fatigue condition (26.1±18.4 to 51.7±20.9 N preferred leg and 11.6±8.94 to 19.4±20.5 N non-preferred leg) suggesting previous injury has a different effect on fatigue response. Horizontal force production during the repeated-sprint test changed by -14% in the preferred kicking leg and -3% in the non-preferred leg (injured group). This represents the preferred kicking leg having a greater fatigue response. In conclusion, the present study has provided a foundation for comparing the injured and non-injured group and the preferred and non-preferred kicking legs during a single leg vertical jump, isokinetic endurance test and repeated-sprint test. These tests provided evidence that the non-preferred leg had greater force production, the preferred leg had greater fatigue response, and the inter-limb difference in force production after fatigue was greater in the injured group. It can be assumed that the preferred kicking leg of the injured group being the previously injured leg has attributed to these results. These results highlights the need for future research to further understanding of the differences in preferred and non-preferred kicking legs, why they occur, and the influence they have on injur

The Role of Subsurface Flows in Solar Surface Convection: Modeling the Spectrum of Supergranular and Larger Scale Flows

We model the solar horizontal velocity power spectrum at scales larger than granulation using a two-component approximation to the mass continuity equation. The model takes four times the density scale height as the integral (driving) scale of the vertical motions at each depth. Scales larger than this decay with height from the deeper layers. Those smaller are assumed to follow a Kolomogorov turbulent cascade, with the total power in the vertical convective motions matching that required to transport the solar luminosity in a mixing length formulation. These model components are validated using large scale radiative hydrodynamic simulations. We reach two primary conclusions: 1. The model predicts significantly more power at low wavenumbers than is observed in the solar photospheric horizontal velocity spectrum. 2. Ionization plays a minor role in shaping the observed solar velocity spectrum by reducing convective amplitudes in the regions of partial helium ionization. The excess low wavenumber power is also seen in the fully nonlinear three-dimensional radiative hydrodynamic simulations employing a realistic equation of state. This adds to other recent evidence suggesting that the amplitudes of large scale convective motions in the Sun are significantly lower than expected. Employing the same feature tracking algorithm used with observational data on the simulation output, we show that the observed low wavenumber power can be reproduced in hydrodynamic models if the amplitudes of large scale modes in the deep layers are artificially reduced. Since the large scale modes have reduced amplitudes, modes on the scale of supergranulation and smaller remain important to convective heat flux even in the deep layers, suggesting that small scale convective correlations are maintained through the bulk of the solar convection zone.Comment: 36 pages, 6 figure

Change in knee flexor torque after fatiguing exercise identifies previous hamstring injury in football players

Muscular fatigue and interlimb strength asymmetry are factors known to influence hamstring injury risk; however, limb‐specific exacerbation of knee flexor (hamstrings) torque production after fatiguing exercise has previously been ignored. To investigate changes in muscular force production before and after sport‐specific (repeated‐sprint) and non‐specific (knee extension‐flexion) fatiguing exercise, and explore the sensitivity and specificity of isokinetic endurance (ie, muscle‐specific) and single‐leg vertical jump (ie, whole limb) tests to identify previous hamstring injury. Twenty Western Australia State League footballers with previous unilateral hamstring injury and 20 players without participated. Peak concentric knee extensor and flexor (180°∙s−1) torques were assessed throughout an isokinetic endurance test, which was then repeated alongside a single‐leg vertical jump test before and after maximal repeated‐sprint exercise. Greater reductions in isokinetic knee flexor torque (−16%) and the concentric hamstring:quadriceps peak torque ratio (−15%) were observed after repeated‐sprint running only in the injured (kicking) leg and only in the previously injured subjects. Changes in (1) peak knee flexor torque after repeated‐sprint exercise, and (2) the decline in knee flexor torque during the isokinetic endurance test measured after repeated‐sprint exercise, correctly identified the injured legs (N = 20) within the cohort (N = 80) with 100% specificity and sensitivity. Decreases in peak knee flexor torque and the knee flexor torque during an isokinetic endurance test after repeated‐sprint exercise identified previous hamstring injury with 100% accuracy. Changes in knee flexor torque, but not SLVJ, should be tested to determine its prospective ability to predict hamstring injury in competitive football players

Reliability and validity of maximal mean and critical speed and metabolic power in Australian youth soccer players

© 2020 Cameron Lord, Anthony J. Blazevich, Chris R. Abbiss, Fadi Ma\u27ayah, published by Sciendo 2020. The reliability and validity of maximal mean speed (MMS), maximal mean metabolic power (MMPmet), critical speed (CS) and critical metabolic power (CPmet) were examined throughout the 2016-2017 soccer National Youth League competitions. Global positioning system (GPS) data were collected from 20 sub-elite soccer players during a battery of maximal running tests and four home matches. A symmetric moving average algorithm was applied to the instantaneous velocity data using specific time windows (1, 5, 10, 60, 300 and 600 s) and peak values were identified. Additionally, CS and CP¬met values calculated from match data were compared to CS and CPmet values determined from previously validated field tests to assess the validity of match values. Intra-class correlation (one-way random absolute agreement) scores ranged from 0.577 to 0.902 for speed, and from 0.701 to 0.863 for metabolic power values. Coefficients of variation (CV) ranged from good to moderate for speed (4-6%) and metabolic power (4-8%). Only CS and CPmet values were significantly correlated (r = 0.842; 0.700) and not statistically different (p = 0.066; 0.271) to values obtained in a shuttle-running critical test. While the present findings identified match-derived MMS, MMPmet, CS and CPmet to be reliable, only CS and CPmet derived from match play were validated to a CS field test that required changes in speed and direction rather than continuous running. This suggests that both maximal mean and critical speed and metabolic power analyses could be alternatives to absolute distance and speed in the assessment of match running performance during competitive matches

Educating the future workforce: building the evidence about interprofessional learning

This paper addresses the theme of interprofessional education for health and social care professionals as it effects on the development of the work force. The drivers for change in the UK, typified by the Bristol Royal Infirmary and Victoria Climbié inquiries and the response to this in the form of Department of Health policy, are discussed. The need for rapid development of the evidence base around this subject is evident form literature reviews of the impact of interprofessional education. Directions for future research and investment in this area are proposed including the need for a stronger theoretical base and for longitudinal studies over extended periods of time in order to examine short, medium and long term outcomes in relation to health care practice

Falls in people with MS--an individual data meta-analysis from studies from Australia, Sweden, United Kingdom and the United States.

BACKGROUND: Falls are common in people with multiple sclerosis (PwMS). Previous studies have generally included small samples and had varied methods. OBJECTIVES: The objectives of this paper are to compile fall rates across a broad range of ages and disease severity and to definitively assess the extent to which MS-associated and demographic factors influence fall rates. METHODS: Individual data from studies in four countries that prospectively measured falls for three months were analyzed. We determined fall rates, prevalence of fallers (≥1 falls) and frequent fallers (≥2 falls), location and timing of falls, and fall-related demographic factors. RESULTS: A total of 537 participants reported 1721 falls: 56% were fallers and 37% frequent fallers. Most falls occurred indoors (65%) between 6 a.m. and 6 p.m. (75%). Primary progressive MS was associated with significantly increased odds of being a faller (odds ratio (OR) 2.02; CI 1.08-3.78). Fall risk peaked at EDSS levels of 4.0 and 6.0 with significant ORs between 5.30 (2.23-12.64) and 5.10 (2.08-12.47). The fall rate was lower in women than men (relative risk (RR) 0.80; CI 0.67-0.94) and decreased with increasing age (RR 0.97 for each year, CI 0.95-0.98). CONCLUSION: PwMS are at high risk of falls and there are important associations between falls and MS-associated disability, gender and age

Fall risk in people with MS: A Physiological Profile Assessment study.

INTRODUCTION: The Physiological Profile Assessment (PPA) is used in research and clinical practice for assessing fall risk. We compared PPA test performance between people with multiple sclerosis (MS) and healthy controls, determined the fall-risk profile for people with MS and developed a reference database for people with MS. METHODS: For this study, 416 ambulant people with MS (51.5 ± 12.0 years) and 352 controls (52.8 ± 12.2 years) underwent the PPA (tests of contrast sensitivity, proprioception, quadriceps strength, reaction time and sway) with composite fall-risk scores computed from these measures. MS participants were followed prospectively for falls for 3 months. RESULTS: The MS participants performed significantly worse than controls in each PPA test. The average composite fall-risk score was also significantly elevated, indicating a "marked" fall risk when compared with controls. In total, 155 MS participants (37.3%) reported 2 + falls in the follow-up period. Frequent fallers performed significantly worse than non-frequent fallers in the contrast sensitivity, reaction time and sway tests and had higher PPA composite scores. CONCLUSIONS: In line with poor PPA test performances, falls incidence in people with MS was high. This study provides comprehensive reference data for the PPA measures for people with MS that could be used to inform future research and clinical practice

A multifactorial intervention for frail older people is more than twice as effective among those who are compliant: complier average causal effect analysis of a randomised trial

AbstractQuestion: What is the effect of a multifactorial intervention on frailty and mobility in frail older people who comply with their allocated treatment? Design: Secondary analysis of a randomised, controlled trial to derive an estimate of complier average causal effect (CACE) of treatment. Participants: A total of 241 frail community-dwelling people aged ≥ 70 years. Intervention: Intervention participants received a 12-month multidisciplinary intervention targeting frailty, with home exercise as an important component. Control participants received usual care. Outcome measures: Primary outcomes were frailty, assessed using the Cardiovascular Health Study criteria (range 0 to 5 criteria), and mobility measured using the 12-point Short Physical Performance Battery. Outcomes were assessed 12 months after randomisation. The treating physiotherapist evaluated the amount of treatment received on a 5-point scale. Results: 216 participants (90%) completed the study. The median amount of treatment received was 25 to 50% (range 0 to 100). The CACE (ie, the effect of treatment in participants compliant with allocation) was to reduce frailty by 1.0 frailty criterion (95% CI 0.4 to 1.5) and increase mobility by 3.2 points (95% CI 1.8 to 4.6) at 12 months. The mean CACE was substantially larger than the intention-to-treat effect, which was to reduce frailty by 0.4 frailty criteria (95% CI 0.1 to 0.7) and increase mobility by 1.4 points (95% CI 0.8 to 2.1) at 12 months. Conclusion: Overall, compliance was low in this group of frail people. The effect of the treatment on participants who comply with allocated treatment was substantially greater than the effect of allocation on all trial participants. Trial registration: Australian and New Zealand Trial Registry ANZCTRN12608000250336. [Fairhall N, Sherrington C, Cameron ID, Kurrle SE, Lord SR, Lockwood K, Herbert RD (2016) A multifactorial intervention for frail older people is more than twice as effective among those who are compliant: complier average causal effect analysis of a randomised trial. Journal of Physiotherapy 63: 40–44

Telehealth and Mobile Health Applied To IntegratedBehavioral Care: OpportunitiesFor Progress In New Hampshire

This paper is an accompanying document to a webinar delivered on May 16, 2017, for the New Hampshire Citizens Health Initiative (Initiative). As integrated behavioral health efforts in New Hampshire gain traction, clinicians, administrators, payers, and policy makers are looking for additional efficiencies in delivering high quality healthcare. Telehealth and mobile health (mHealth) have the opportunity to help achieve this while delivering a robust, empowered patient experience. The promise of video-based technology was first made in 1964 as Bell Telephone shared its Picturephone® with the world. This was the first device with audio and video delivered in an integrated technology platform. Fast-forward to today with Skype, FaceTime, and webinar tools being ubiquitous in our personal and business lives, but often slow to be adopted in the delivery of medicine. Combining technology-savvy consumers with New Hampshire’s high rate of electronic health record (EHR) technology adoption, a fairly robust telecommunications infrastructure, and a predominately rural setting, there is strong foundation for telehealth and mHealth expansion in New Hampshire’s integrated health continuum

The relationship between physiological and perceived fall risk in people with multiple sclerosis: implications for assessment and management

Objective: This study evaluated the relationship between physiological and perceived fall risk in people with multiple sclerosis (MS). Design: Secondary analysis of data from prospective cohort studies undertaken in Australia, the United Kingdom, and the United States. Setting: Community. Participants: Ambulatory people with MS (N=416) (age 51.5±12.0 years; 73% female; 62% relapsing-remitting MS; 13.7±9.9 years disease duration). Interventions: Not applicable. Main Outcome Measures: All participants completed measures of physiological (Physiological Profile Assessment [PPA]) and perceived (Falls Efficacy Scale-international [FESi]) fall risk and prospectively recorded falls for 3 months. Results: 155 (37%) of the participants were recurrent fallers (≥2 falls). Mean PPA and FESi scores were high (PPA 2.14±1.87, FESi 34.27±11.18). The PPA and the FESi independently predicted faller classification in logistic regression, which indicated that the odds of being classified as a recurrent faller significantly increased with increasing scores (PPA odds ratio [OR] 1.30 [95% CI 1.17-1.46], FESi OR 1.05 [95% CI 1.03-1.07]). Classification and regression tree analysis divided the sample into four groups based on cutoff values for the PPA: (1) low physiological/low perceived risk (PPA 27.5), (3) high physiological/low perceived risk (PPA >2.83, FESi 35.5). Over 50% of participants had a disparity between perceived and physiological fall risk; most were in group 2. It is possible that physiological risk factors not detected by the PPA may also be influential. Conclusions: This study highlights the importance of considering both physiological and perceived fall risk in MS and the need for further research to explore the complex interrelationships of perceptual and physiological risk factors in this population. This study also supports the importance of developing behavioral and physical interventions that can be tailored to the individual's needs