Loading range for the development of peak power in the close-grip bench press versus the traditional bench press

The close-grip bench press (CGBP) is a variation of the traditional bench press (TBP) that uses a narrower grip (~95% biacromial distance) and has application for athletes performing explosive arm actions where the hands are positioned close to the torso. Limited research has investigated CGBP peak power. Twenty-six strength-trained individuals completed a one-repetition maximum TBP and CGBP. During two other sessions, subjects completed two repetitions as explosively as possible with loads from 20% to 90% for each exercise, with peak power measured by a linear position transducer. A factorial ANOVA calculated between- and within-exercise differences in peak power. Partial correlations controlling for sex determined relationships between absolute and relative strength and peak power load. Peak power for the TBP occurred at 50% 1RM, and 30% 1RM for the CGBP. There were no significant (p = 0.680) differences between peak power at each load when comparing the TBP and CGBP. For the within-exercise analysis, there were generally no significant differences in TBP and CGBP peak power for the 20–50% 1RM loads. There were no significant relationships between strength and peak power load (p = 0.100–0.587). A peak power loading range of 20–50% 1RM for the TBP and CGBP is suggested for strength-trained individual

The mechanics of front leg loading during cricket fast bowling: delivery variations, spell demands, and the effects of strength training

The goal of fast bowling in cricket is to dismiss a batsman for as few runs as possible. To assist this goal, fast bowlers will attempt to maximise ball release velocity (BRV) to decrease the decision-making and stroke execution time of the opposing batsmen. Fast bowlers will also employ various delivery lengths (i.e. short, good and full) to assist in affecting a batsman’s stroke execution. Several issues remain to be addressed with regards to the biomechanical assessment of fast bowling. This is particularly evident when analysing fast bowling performance (i.e. BRV), the implications of front foot loading (i.e. vertical and braking ground reaction forces [GRFs]) and the associated kinematics (i.e. knee, shoulder, and trunk angles). The biomechanics of delivery lengths, spell demands, periodised strength training interventions, and the potential to conduct biomechanical analyses during match-play, have received limited attention within the scientific literature with respect to fast bowling. Therefore, the purpose of this thesis was fourfold: 1) determine if changes in delivery length necessitate acute alterations in fast bowling biomechanics and BRV; 2) identify whether an extended eight-over bowling spell resulted in changes in biomechanics or performance within different delivery lengths; 3) assess the chronic effects of a periodised strength training intervention upon front foot loading and performance in fast bowlers; and 4) investigate the reliability and validity of inertial measure unit (IMU) derived trunk and tibia accelerations with respect to GRF during front foot contact (FFC). This series of studies provides valuable information about the implications of delivery length, spell demands and the influence of strength training upon fast bowling biomechanics and performance, as well as the first investigation on the reliability and validity of segmental load measures in comparison to FFC GRF for fast bowlers. Study 1 outlined that changes in delivery length did not necessitate alterations in fast bowling biomechanics or BRV. Therefore, it appeared that fast bowlers were able to employ different delivery lengths without significant changes in their technique, which is ultimately beneficial to the goal of fast bowling. Study 2 demonstrated that an extended eight-over bowling spell did not result in any biomechanical or performance differences when comparing the average of the first and last three overs. Fast bowlers were able to maintain their technique and FFC loading patterns during a single extended bowling spell, which provided support to current bowling workload monitoring practices. Study 3 demonstrated that an eight-week periodised strength training program can elicit significant improvements in strength and lower-limb eccentric capacity among fast bowlers. However, this had minimal impact upon FFC GRFs, with no significant changes in BRV between pre- and post-testing. These findings may indicate that a combined approach of strength and skill training is necessary for improvements in BRV. Study 4 documented that IMU derived trunk and tibia segment accelerations were reliable, but not a valid representation of GRF during FFC. With further investigation, segment acceleration could be a useful measure for fast bowling performance and biomechanics, but does not provide an appropriate representation of GRF during FFC

The metabolic syndrome and neuropathy: Therapeutic challenges and opportunities

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110888/1/ana23986.pd

New times, new politics: history and memory during the final years of the CPGB

This article examines the relationship between collective memory, historical interpretation and political identity. It focuses on the dissolution of the Communist Party of Great Britain (CPGB) as constructed through collective narrative memory, and on Marxist interpretations of history. The divisions within the party and the wider Marxist community, stretching from 1956 until 1991, were often framed around questions of historical interpretation. The events of 1989–1991 created an historical and mnemonic crisis for CPGB members who struggled to reconcile their past identities with their present situation. Unlike the outward-facing revisionism of other political parties, this was an intensely personal affair. The solution for many was to emphasise the need to find new ways to progress socialist aims, without relying on a discredited grand narrative. In contrast, other Communist parties, such as the Communist Party of Britain, which had been established (or ‘re-established’) in 1988, fared rather better. By adhering to the international party line of renewal and continued struggle, the party was able to hold its narrative together, condemning the excesses of totalitarian regimes, while reaffirming the need for international class struggle

Gait analysis of fixed bearing and mobile bearing total knee prostheses during walking: Do mobile bearings offer functional advantages?

Background - Limited previous findings have detailed biomechanical advantages following implantation with mobile bearing (MB) prostheses after total knee replacement (TKR) surgery during walking. The aim of this study was to compare three dimensional spatiotemporal, kinematic, and kinetic parameters during walking to examine whether MBs offer functional advantages over fixed bearing (FB) designs. Methods - Sixteen patients undergoing primary unilateral TKR surgery were randomised to receive either a FB (n = 8) or MB (n = 8) total knee prosthesis. Eight age and gender matched controls underwent the same protocol on one occasion. A 12 camera Vicon system integrated with four force plates was used. Patients were tested pre-surgery and nine months post-surgery. Results - No significant differences between FB and MB groups were found at any time point in the spatiotemporal parameters. The MB group was found to have a significantly reduced frontal plane knee range of motion (ROM) at pre-surgery than the FB group (FB = 14.92 ± 4.02°; MB = 8.87 ± 4.82°), with the difference not observed post-surgery. No further significant kinematic or kinetic differences were observed between FB and MB groups. Fixed bearing and MB groups both displayed spatiotemporal, kinematic, and kinetic differences when compared to controls. Fixed bearing and MB groups differed from controls in six and five parameters at nine months post-surgery, respectively. Conclusions - No functional advantages were found in knees implanted with MB prostheses during walking, with both groups indicative of similar differences when compared to normal knee biomechanics following prosthesis implantation

Lower-body power, linear speed, and change-of-direction speed in Division I collegiate women\u27s volleyball players

© 2020 Institute of Sport. All rights reserved. Volleyball players need to sprint and change direction during a match. Lower-body power, often measured by jump tests, could contribute to faster movements. How different jumps relate to linear and change-of-direction (COD) speed has not been analyzed in Division I (DI) collegiate women\u27s volleyball players. Fifteen female volleyball players completed the vertical jump (VJ), two-step approach jump (AppJ), and standing broad jump (SBJ). Peak power and power-to-body mass ratio (P:BM) were derived from VJ and AppJ height; relative SBJ was derived from SBJ distance. Linear speed was measured via a 20-m sprint (0-10 and 0-20 m intervals); COD speed was measured using the pro-agility shuttle. Pearson\u27s correlations (p \u3c 0.05) calculated relationships between the power variables, and speed tests. There were no significant relationships between the power variables and the 0-10 m sprint interval. Greater VJ height (r = -0.534) and P:BM (r = -0.557) related to a faster 0-20 m sprint interval. This be due to a greater emphasis on the stretch-shortening cycle to generate speed over 20 m. However, although a 20-m sprint may provide a measure of general athleticism, the distance may not be specific to volleyball. This was also indicated as the AppJ did not relate to any of the speed tests. Nonetheless, VJ height and P:BM, and SBJ distance and relative SBJ, all negatively correlated with the pro-agility shuttle (r = -0.548 to -0.729). DI women\u27s collegiate volleyball players could develop absolute and relative power in the vertical and horizontal planes to enhance COD speed

An assessment of radiation models utilized in CFD for thermal and fluid analysis in interior building spaces with large glazing

This paper investigates the effects of using the S2S and the DO method in the CFD simulation of a cavity to identify a convenient model for simulating radiative heat transfer. A 3D model for an office room fitted with a sizeable controllable glass window was developed to carry out a transient analysis of a room's thermal performance when the glass is at its opaque state while accounting for each of the models. A transient user-defined function (UDF) boundary condition, based on radiative heat flux, was set as an incident solar load boundary condition on the dynamic glazing to study the dispersed temperature and the airflow in the room. Various configurations of the enclosed room with initial wall boundary condition and airflow in the room were considered under the effects of different parameters such as thermal properties, Rayleigh (Ra) and Grashof (Gr) numbers, surface emissivity, and absorption. Radiative CFD results were compared, and the importance of accounting for radiation was noted. The S2S displayed good performance, whereas unexpected temperature distribution was observed with the DO method. Although heat transfer depends on the transmitting material's thermal properties, further analysis has shown that the S2S, along with the SST k-ꞷ viscous turbulence model, using piecewise linear approximation, is a reliable CFD model setting for performing a thermal analysis of a highly glazed enclosed room. The results were also compared to a previous 2D analysis of an enclosed space without accounting for radiation. Results had shown that the interior temperature was less than 2% for the S2S when radiation was overlooked. Further study would involve the validation of the computed room temperature with experimental data which will show the efficiency of the two radiation model methods in performing the thermal performance of a building.ye

The effects of lateral bounds on post-activation potentiation of change-of-direction speed measured by the 505 test in college-aged men and women

Forty recreationally-trained individuals completed four testing sessions to determine whether lateral bounds (LB) or weighted lateral bounds enhanced change-of-direction (COD) speed measured by the 505 COD speed test. Session 1 included vertical jump and lateral bound (LB) testing to measure power. Sessions 2-4 involved three randomized conditioning activities (CA): 3 × 5 LB; 3 × 5 weighted LB (10% body mass provided by a weighted vest); and a control condition (4-min rest). The 505 COD speed test was performed 5- and 2.5-min pre-CA, and ~15 s, 4, 8, 12, and 16 min post-CA. A 3 × 6 repeated measures analysis of variance (ANOVA) calculated performance changes across time points post-CA. A 3 × 2 repeated measures ANOVA analyzed best potentiated performance. Smallest worthwhile change (SWC) measured within-subject 505 COD speed test performance. Partial correlations controlling for sex calculated relationships between the vertical jump, LB, and percent potentiation. There were no differences ( = 0.919) in 505 time relative to baseline for any CA, nor was the SWC exceeded. The best potentiated 505 time was faster ( \u3c 0.001) than baseline for all CA, with no between-CA differences. There were no significant ( = 0.056-0.993) correlations between power and potentiation. LB and weighted LB did not potentiate the 505 COD speed test, although performance was not hindered

EXAMINING THE IMPACT OF APPROACH AND EXIT PHASE STRATEGIES ON CHANGE OF DIRECTION PERFORMANCE: A NOVEL METHODOLOGY

This study used new insole pressure technology to examine how movement strategies during approach and exit phases affect change of direction (COD) times. Participants (n=26) wore NURVV smart insoles and performed 90˚ cuts off each leg (dominant [Dom] and non-dominant [ND]). Ground contact time (GCT), cadence, centre of pressure, and return to linear sprinting metrics were analysed for four steps about the cut-step. Faster cadence and a more forefoot strike pattern predicted 58% of the variance in Dom side COD ability. ND COD ability was predicted by a faster cadence immediately post-cut and a quicker GCT two steps before the cut-step (66% of variance explained). These findings emphasize the approach phase’s crucial role in COD ability and stress the need to examine multiple steps around the cut-step for a complete understanding of COD mechanisms

A preliminary investigation into the relationship between functional movement screen scores and athletic physical performance in female team sport athletes

There is little research investigating relationships between the Functional Movement Screen (FMS) and athletic performance in female athletes. This study analyzed the relationships between FMS (deep squat; hurdle step [HS]; in-line lunge [ILL]; shoulder mobility; active straight-leg raise [ASLR]; trunk stability push-up; rotary stability) scores, and performance tests (bilateral and unilateral sit-and-reach [flexibility]; 20-m sprint [linear speed]; 505 with turns from each leg; modified T-test with movement to left and right [change-of-direction speed]; bilateral and unilateral vertical and standing broad jumps; lateral jumps [leg power]). Nine healthy female recreational team sport athletes (age = 22.67 ± 5.12 years; height = 1.66 ± 0.05 m; body mass = 64.22 ± 4.44 kilograms) were screened in the FMS and completed the afore-mentioned tests. Percentage between-leg differences in unilateral sit-and-reach, 505 turns and the jumps, and difference between the T-test conditions, were also calculated. Spearman\u27s correlations (p = 0.05) examined relationships between the FMS and performance tests. Stepwise multiple regressions (p = 0.05) were conducted for the performance tests to determine FMS predictors. Unilateral sit-and-reach positive correlated with the left-leg ASLR (r = 0.704-0.725). However, higher-scoring HS, ILL, and ASLR related to poorer 505 and T-test performance (r = 0.722-0.829). A higher-scored left-leg ASLR related to a poorer unilateral vertical and standing broad jump, which were the only significant relationships for jump performance. Predictive data tended to confirm the correlations. The results suggest limitations in using the FMS to identify movement deficiencies that could negatively impact athletic performance in female team sport athletes