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

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

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 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

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

The Effects of the Barbell Hip Thrust on Post-Activation Performance Enhancement of Change of Direction Speed in College-Aged Men and Women

This study investigated whether the barbell hip thrust (BHT) enhanced change-of-direction (COD) speed measured by the 505 COD speed test. Forty recreationally trained individuals completed three sessions. Session 1 included one-repetition maximum (1RM) BHT testing to measure absolute and relative strength. Sessions 2 and 3 involved two counter-balanced conditioning activities (CAs): 3 sets × 5 repetitions of the BHT at 85% 1RM and a control condition (CC; 6 min rest). The 505 COD speed test was performed 5 and 2.5 min pre-CA, and 4, 8, 12, and 16 min post-CA in each session. A 2 × 5 repeated-measures ANOVA (p 0.05) calculated performance changes across time post-CA. A 2 × 2 repeated-measures ANOVA analyzed best potentiated performance. Partial correlations controlling for sex calculated relationships between the 1RM BHT and 505 COD speed test percent potentiation. There was a significant main effect for time (p 0.001), but not for condition (p = 0.271) or condition × time (p = 0.295). There were no significant correlations between 1RM BHT and potentiation. The 85% 1RM BHT did potentiate the 505 4−16 min post-CA but no more than the CC. Nonetheless, a heavy BHT could be programmed prior to COD drills as COD speed could be potentiated and performance improved in men and women

Effects of Preventative Ankle Taping on Planned Change-of-Direction and Reactive Agility Performance and Ankle Muscle Activity in Basketballers

This study investigated the effects of preventative ankle taping on planned change-of-direction and reactive agility performance and peak ankle muscle activity in basketballers. Twenty male basketballers (age = 22.30 ± 3.97 years; height = 1.84 ± 0.09 meters; body mass = 85.96 ± 11.88 kilograms) with no ankle pathologies attended two testing sessions. Within each session, subjects completed six planned and six reactive randomized trials (three to the left and three to the right for each condition) of the Y-shaped agility test, which was recorded by timing lights. In one session, subjects had both ankles un-taped. In the other, both ankles were taped using a modified subtalar sling. Peak tibialis anterior, peroneus longus (PL), peroneus brevis (PB), and soleus muscle activity was recorded for both the inside and outside legs across stance phase during the directional change, which was normalized against 10-meter sprint muscle activity (nEMG). Both the inside and outside cut legs during the change-of-direction step were investigated. Repeated measures ANOVA determined performance time and nEMG differences between un-taped and taped conditions. There were no differences in planned change-of-direction or reactive agility times between the conditions. Inside cut leg PL nEMG decreased when taped for the planned left, reactive left, and reactive right cuts (p = 0.01). Outside leg PB and soleus nEMG increased during the taped planned left cut (p = 0.02). There were no other nEMG changes during the cuts with taping. Taping did not affect change-of-direction or agility performance. Inside leg PL activity was decreased, possibly due to the tape following the line of muscle action. This may reduce the kinetic demand for the PL during cuts. In conclusion, ankle taping did not significantly affect planned change-of-direction or reactive agility performance, and did not demonstrate large changes in activity of the muscle complex in healthy basketballers

The effects of an eight over Cricket bowling spell upon pace bowling biomechanics and performance within different delivery lengths

Pace bowlers must often perform extended bowling spells with maximal ball release speed (BRS) while targeting different delivery lengths when playing a multi-day match. This study investigated the effect of an eight over spell upon pace bowling biomechanics and performance at different delivery lengths. Nine male bowlers (age = 18.8 ± 1.7 years) completed an eight over spell, while targeting different lengths (short: 7–10 m, good: 4–7 m, full: 0–4 m from the batter’s stumps, respectively) in a randomized order. Trunk, knee and shoulder kinematics and ground reaction forces at front foot contact (FFC), as well as run-up velocity and BRS were measured. Paired sample t-tests (p ≤ 0.01), Hedges’ g effect sizes, and statistical parametrical mapping were used to assess differences between mean variables from the first and last three overs. No significant differences (p = 0.05–0.98) were found in any discrete or continuous variables, with the magnitude of difference being trivial-to-medium (g = 0.00–0.73) across all variables. Results suggest pace bowlers sustain BRS through a single eight over spell while tolerating the repeatedly high whole-body biomechanical loads as suggested by maintaining the kinematics or technique at the assessed joints during FFC. Practically, the findings are advantageous for bowling performance and support current bowling load monitoring practices

Characteristics and outcomes among US patients hospitalized for ischemic stroke before vs during the COVID-19 pandemic

Importance: After the emergence of COVID-19, studies reported a decrease in hospitalizations of patients with ischemic stroke (IS), but there are little to no data regarding hospitalizations for the remainder of 2020, including outcome data from a large cohort of patients with IS and comorbid COVID-19. Objective: To assess hospital discharge rates, demographic factors, and outcomes of hospitalization associated with the COVID-19 pandemic among US patients with IS before vs during the COVID-19 pandemic. Design, Setting, and Participants: This retrospective cohort study used data from the Vizient Clinical Data Base on 324 013 patients with IS at 478 nonfederal hospitals in 43 US states between January 1, 2019, and December 31, 2020. Patients were eligible if they were admitted to the hospital on a nonelective basis and were not receiving hospice care at the time of admission. A total of 41 166 discharged between January and March 2020 were excluded from the analysis because they had unreliable data on COVID-19 status, leaving 282 847 patients for the study. Exposure: Ischemic stroke and laboratory-confirmed COVID-19. Main Outcomes and Measures: Monthly counts of discharges among patients with IS in 2020. Demographic characteristics and outcomes, including in-hospital death, among patients with IS who were discharged in 2019 (control group) were compared with those of patients with IS with or without comorbid COVID-19 (COVID-19 and non-COVID-19 groups, respectively) who were discharged between April and December 2020. Results: Of the 282 847 patients included in the study, 165 912 (50.7% male; 63.4% White; 26.3% aged ≥80 years) were allocated to the control group; 111 418 of 116 935 patients (95.3%; 51.9% male; 62.8% White; 24.6% aged ≥80 years) were allocated to the non-COVID-19 group and 5517 of 116 935 patients (4.7%; 58.0% male; 42.5% White; 21.3% aged ≥80 years) to the COVID-19 group. A mean (SD) of 13 846 (553) discharges per month among patients with IS was reported in 2019. Discharges began decreasing in February 2020, reaching a low of 10 846 patients in April 2020 before returning to a prepandemic level of 13 639 patients by July 2020. A mean (SD) of 13 492 (554) discharges per month was recorded for the remainder of 2020. Black and Hispanic patients accounted for 21.4% and 7.0% of IS discharges in 2019, respectively, but accounted for 27.5% and 16.0% of those discharged with IS and comorbid COVID-19 in 2020. Compared with patients in the control and non-COVID-19 groups, those in the COVID-19 group were less likely to smoke (16.0% vs 17.2% vs 6.4%, respectively) and to have hypertension (73.0% vs 73.1% vs 68.2%) or dyslipidemia (61.2% vs 63.2% vs 56.6%) but were more likely to have diabetes (39.8% vs 40.5% vs 53.0%), obesity (16.2% vs 18.4% vs 24.5%), acute coronary syndrome (8.0% vs 9.2% vs 15.8%), or pulmonary embolus (1.9% vs 2.4% vs 6.8%) and to require intubation (11.3% vs 12.3% vs 37.6%). After adjusting for baseline factors, patients with IS and COVID-19 were more likely to die in the hospital than were patients with IS in 2019 (adjusted odds ratio, 5.17; 95% CI, 4.83-5.53; National Institutes of Health Stroke Scale adjusted odds ratio, 3.57; 95% CI, 3.15-4.05). Conclusions and Relevance: In this cohort study, after the emergence of COVID-19, hospital discharges of patients with IS decreased in the US but returned to prepandemic levels by July 2020. Among patients with IS between April and December 2020, comorbid COVID-19 was relatively common, particularly among Black and Hispanic populations, and morbidity was high

RELATIONSHIPS BETWEEN ARM SPAN AND THE MECHANICS OF THE ONE-REPETITION MAXIMUM TRADITIONAL AND CLOSE-GRIP BENCH PRESS

The traditional bench press (TBP), performed with a grip width that maximizes strength, is a popular exercise for developing the upper-body. The close-grip bench press (CGBP) is a variation of the TBP often used to emphasize the triceps brachii over prime movers such as the pectoralis major. An individual’s arm span (AS; distance between the middle fingers of each hand while the arms are outstretched) could affect the mechanics of each exercise, which may be exacerbated by the change in grip. This study investigated relationships between AS and TBP and CGBP mechanics in resistance-trained men. Twenty-one participants completed a one-repetition maximum (1RM) TBP and CGBP. The TBP was performed with the preferred grip (measured relative to biacromial distance [BAD]), and the CGBP with a grip width of 95% BAD. A linear position transducer measured: lift distance; peak and mean power, velocity, and force; the distance and time when peak power occurred; and work. Pearson’s correlations (r; p < 0.05) computed relationships between AS and TBP and CGBP mechanics. There were significant positive relationships between AS and TBP lift distance and work (r = 0.46 and 0.51, respectively). For the CGBP, there was a significant positive relationship between AS and work (r = 0.48). There were no other significant correlations between AS and lift mechanics. Resistance-trained men with a longer AS may move the bar further and perform more work in the 1RM TBP and CGBP. This could influence how coaches measure training volume, and intensity for individuals with different AS