Daniel D. Cohen

Physiological Testing of Basketball Players: Toward a Standard Evaluation of Anaerobic Fitness

Delextrat, A and Cohen, D. Physiological testing of basketball players: toward a standard evaluation of anaerobic fitness. J Strength Cond Res 00: 1-7, 2008-The aim of this study was to examine whether the changes in the rules of the game instituted in 2000 have modified the physiological factors of success in basketball. The performances of 8 elite male players and 8 average-level players were compared in order to identify which components of fitness among agility, speed, anaerobic power, anaerobic capacity, and upper body strength were key determinants of performance in modern basketball. Each subject performed 7 tests, including vertical jump (VJ), 20-m sprint, agility T test, suicide sprint, 30-second Wingate anaerobic test (WAnT), isokinetic testing of the knee extensors, and 1 repetition maximum (1RM) bench press test. The statistical difference in the anaerobic performances was assessed by Students t test. The main results showed that, compared to average-level players, elite-level players achieved significantly better performances in the agility T test (+6.2%), VJ test (+8.8%), peak torques developed by knee extensors (+20.2%), and 1RM bench press (+18.6%, p < 0.05). In contrast, no significant difference between groups was observed on 20-m sprint, suicide run, and parameters of the WAnT (p > 0.05). These results emphasized the importance of anaerobic power in modern basketball, whereas anaerobic capacity does not seem to be a key aspect to consider. In this context, coaches are advised to avoid using exercises lasting ≥30 seconds in their physical fitness programs, but instead to focus on short and intense tests such as VJ, agility T test, and sprints over very short distances (5 or 10 m).

Ten-year secular changes in muscular fitness in English children

1.Faculty of Life Sciences, London Metropolitan University, London, UK2.Department of Biological Sciences, University of Essex, Colchester, UK3.Centre for Research in Human Development, Concordia University, Montreal, QC, CanadaCorrespondenceDD Cohen, Faculty of Life Sciences, London Metro-politan University, London, UK.Tel: +44 207 133 4687 |Fax: +44 0207 133 4149 |Email: d.cohen@londonmet.ac.ukReceived8 October 2010; revised 25 February 2011;accepted 8 April 2011.DOI:10.1111/j.1651-2227.2011.02318.x

Strength, Power, Speed, and Agility of Women Basketball Players According to Playing Position

Delextrat, A and Cohen, D. Strength, power, speed, and agility of women basketball players according to playing position. J Strength Cond Res 23(7): 1974-1981, 2009-The aim of the present study was to investigate the effect of playing position on strength, power, speed, and agility performances of women basketball players. Thirty subjects playing at national level participated in this study. They were divided into 3 groups according to playing position: guards (positions 1 and 2), forwards (positions 3 and 4), and centers (position 5). Each subject performed 8 tests presented in a random order: The 30-second Wingate Anaerobic test (WAnT), isokinetic testing of the knee extensors, 2 types of jump tests, a 20-m sprint, the agility T-test, a suicide run, and a basketball chest pass. Statistical differences between playing positions were assessed using a 1-way analysis of variance (ANOVA) and Scheffe post hoc analyses. Results showed that guards performed significantly better than centers for the relative peak and mean power achieved during the WAnT (+13% and +16.9%, respectively), relative peak torque of knee extensors (+19.5%), single-leg jump (+21.8), suicide run (+7.5%), and agility T-test (+6.4%, p < 0.05). In addition, guards achieved significantly better performances than forwards in the suicide run test (+7.1%) and forwards were characterized by a greater peak torque of the knee extensors compared to centers (+22.1%). These results indicate that specific fitness training must be undertaken according to playing position. The ability to perform the suicide run, the single-leg jump, and the different movements involved in the agility T-test must be developed in guards. In contrast, speed over short distances and strength development of lower body and upper body should be performed by all playing positions.

Low muscle strength is associated with metabolic risk factors in Colombian children: the ACFIES study.

Purpose In youth, poor cardiorespiratory and muscular strength are associated with elevated metabolic risk factors. However, studies examining associations between strength and risk factors have been done exclusively in high income countries, and largely in Caucasian cohorts. The aim of this study was to assess these interactions in schoolchildren in Colombia, a middle income Latin American country. Methods We measured body mass index, body composition, handgrip strength (HG), cardiorespiratory fitness (CRF) and metabolic risk factors in 669 low-middle socioeconomic status Colombian schoolchildren (mean age 11.52±1.13, 47% female). Associations between HG, CRF and metabolic risk factors were evaluated. Results HG and CRF were inversely associated with blood pressure, HOMA index and a composite metabolic risk score (p<0.001 for all) and HG was also inversely associated with triglycerides and C-reactive protein (CRP) (both p<0.05). Associations between HG and risk factors were marginally weakened after adjusting for CRF, while associations between CRF and these factors were substantially weakened after adjusting for HG. Linear regression analyses showed inverse associations between HG and systolic BP (β = −0.101; p = 0.047), diastolic BP (β = −0.241; p> = 0.001), HOMA (β = −0.164; p = 0.005), triglycerides (β = −0.583; p = 0.026) and CRP (β = −0.183; p = 0.037) but not glucose (p = 0.698) or HDL cholesterol (p = 0.132). The odds ratios for having clustered risk in the weakest quartile compared with the strongest quartile were 3.0 (95% confidence interval: 1.81–4.95). Conclusions In Colombian schoolchildren both poorer handgrip strength/kg body mass and cardiorespiratory fitness were associated with a worse metabolic risk profile. Associations were stronger and more consistent between handgrip and risk factors than between cardiorespiratory fitness and these risk factors. Our findings indicate the addition of handgrip dynamometry to non-invasive youth health surveillance programs would improve the accuracy of the assessment of cardio-metabolic health.

The Impact of the FIFA 11+ Training Program on Injury Prevention in Football Players: A Systematic Review

The FIFA 11+ is a simple, and easy to implement, sports injury prevention program comprising a warm up of 10 conditioning exercises. The aim of this systematic review was to evaluate the impact of the FIFA 11+ on injury incidence, compliance and cost effectiveness when implemented among football players. MEDLINE, EMBASE and Scopus databases were searched using the search terms “FIFA 11+”, “football”, “soccer”, “injury prevention”, and “The 11”. The titles and abstracts were screened by two independent reviewers and the data were filtered by one reviewer using a standardized extraction form and thereafter checked by another one. The risk of bias and the methodological quality of the studies were evaluated through the PEDro score and Critical Appraisal Skills Programme (CASP). A total of 911 studies were identified, of which 12 met the inclusion criteria of the review. The FIFA 11+ has demonstrated how a simple exercise program completed as part of warm-up can decrease the incidence of injuries in amateur football players. In general, considerable reductions in the number of injured players, ranging between 30% and 70%, have been observed among the teams that implemented the FIFA 11+. In addition, players with high compliance to the FIFA 11+ program had an estimated risk reduction of all injuries by 35% and show significant improvements in components of neuromuscular and motor performance when participating in structured warm-up sessions at least 1.5 times/week. Most studies had high methodological quality and a low risk of bias. Given the large number of people who play football at amateur level and the detrimental impact of sports injuries on a personal and societal level, the FIFA 11+ can be considered as a fundamental tool to minimize the risks of participation in a sport with substantial health benefits.

Handgrip strength in English schoolchildren

Aims:  The aims of this study were to evaluate patterns of handgrip (HG) strength in relation to gender and age in English schoolchildren and to compare this with existing data and produce reference data for this population.

Vertical jumping and leg power normative data for English school children aged 10-15 years.

Abstract Although vertical jumping is often incorporated into physical activity tests for both adults and children, normative data for children and adolescents are lacking in the literature. The objectives of this study were to provide normative data of jump height and predicted peak leg power for males and females aged 10.0–15.9 years. Altogether, 1845 children from 12 state primary and secondary schools in the East of England participated in the study. Each child performed two countermovement jumps, and jump height was calculated using a NewTest jump mat. The highest jump was used for analysis and in the calculation of predicted peak power. Jump height and predicted peak leg power were significantly higher for males than females from the age of 11 years. Jump height and peak power increased significantly year on year for males. For females, jump height and predicted peak leg power reached a plateau after age 12 and 13 years respectively. This study provides normative data that can be used as a tool to classify jumping performance in children aged 10–15 years.

Association of handgrip strength to cardiovascular mortality in pre-diabetic and diabetic patients: A subanalysis of the ORIGIN trial

acute heart failure with renal dysfunction: the ROSE acute heart failure randomized trial. JAMA 2013;310:2533–43. [5] GheorghiadeM, Follath F, Ponikowski P, et al. Assessing and grading congestion in acute heart failure: a scientific statement from the AcuteHeart Failure Committee of theHeart Failure Association of the European Society of Cardiology andendorsed by the European Society of Intensive Care Medicine. Eur J Heart Fail 2010;12:423–33. [6] Nunez J, Nunez E, Sanchis J, et al. Antigen carbohydrate 125 and brain natriuretic peptide serial measurements for risk stratification following an episode of acute heart failure. Int J Cardiol 2012;159:21–8. [7] Givertz MM, Postmus D, Hillege HL, et al. Renal function trajectories and clinical outcomes in acute heart failure. Circ Heart Fail 2014;7:59–67. [8] MetraM, Davison B, Bettari L, et al. Is worsening renal function an ominous prognostic sign inpatientswith acute heart failure? The role of congestion and its interactionwith renal function. Circ Heart Fail 2012;5:54–62. [9] Rogers JK, Pocock SJ, McMurray JJ, et al. Analysing recurrent hospitalizations in heart failure: a review of statistical methodology, with application to CHARM-Preserved. Eur J Heart Fail 2014;16:33–40.

Centile curves and normative values for the twenty metre shuttle-run test in English schoolchildren

Abstract The aim of this study was to provide normative data for performance on the 20 m shuttle-run test of cardiorespiratory fitness in English schoolchildren. A total of 7366 10–16 year olds completed the 20 m shuttle-run test. We expressed performance as the number of shuttles completed, test score (shuttles and levels) and estimated peak oxygen consumption ([Vdot]O2peak). We calculated descriptive statistics for each age-sex group to construct percentile curves and tables. To assess the cardiorespiratory fitness of our sample, we calculated the number of participants who fell below proposed cut-offs for low cardiorespiratory fitness based on either completed shuttles or [Vdot]O2peak. These cut-offs did not agree in terms of frequency of classification. The classification based on estimated [Vdot]O2peak suggested low fitness was more prevalent in males and that the incidence of low fitness increased with age in both sexes. These are the first normative data for shuttle-run performance in English youth and can now be used to interpret data from this cardiorespiratory fitness test. The two cut-offs used for low fitness did not agree and future research should establish a cut-off for test performance which can predict present or future ill-health

Angle-Specific Eccentric Hamstring Fatigue After Simulated Soccer

PURPOSE To evaluate the effect of simulated soccer on the hamstrings eccentric torque-angle profile and angle of peak torque (APTeccH), and on the hamstrings:quadriceps torque ratio at specific joint angles (ASHecc:Qcon). METHODS The authors assessed dominant-limb isokinetic concentric and eccentric knee flexion and concentric knee extension at 120°/s in 9 semiprofessional male soccer players immediately before and after they completed the Loughborough Intermittent Shuttle Test (LIST). RESULTS The LIST resulted in significant decreases in eccentric hamstrings torque at 60°, 50°, and 10° and a significant (21.8%) decrease in ASHecc:Qcon at 10° (P < .05). APTeccH increased from 7.1° ± 1.0° to 18.8° ± 4.2° (P < .05). Eccentric hamstrings peak torque significantly declined from 185.1 ± 70.4 N·m pre-LIST to 150.9 ± 58.5 N·m post-LIST (P = .002), but there were no significant changes in hamstrings or quadriceps concentric peak torque (P = .312, .169, respectively). CONCLUSIONS Simulated soccer results in a selective loss of eccentric hamstrings torque and hamstrings-to-quadriceps muscle balance at an extended joint position and a shift in the eccentric hamstrings APT to a shorter length, changes that could increase vulnerability to hamstrings injury. These findings suggest that injury-risk screening could be improved by evaluating the eccentric hamstrings torque-angle profile and hamstrings strength-endurance and that the development of hamstrings fatigue resistance and long-length eccentric strength may reduce injury incidence.