Dr Robert Lockie

© 2018 Informa UK Limited, trading as Taylor & Francis Group This study assessed the reliability and validity of segment measured accelerations in comparison to front foot contact (FFC) ground reaction force (GRF) during the delivery stride for cricket pace bowlers. Eleven recreational bowlers completed a 30-delivery bowling spell. Trunk- and tibia-mounted inertial measurement units (IMUs) were used to measure accelerations, converted to force, for comparisons to force plate GRF discrete measures. These measures included peak force, impulse and the continuous force¿time curve in the vertical and braking (horizontal) planes. Reliability and validity was determined by intra-class correlation coefficients (ICC), coefficient of variation (CV), Bland¿Altman plots, paired sample t-tests, Pearson¿s correlation and one-dimensional (1D) statistical parametrical mapping (SPM). All ICC (0.90¿0.98) and CV (4.23¿7.41%) were acceptable, except for tibia-mounted IMU braking peak force (CV = 12.44%) and impulse (CV = 18.17%) and trunk vertical impulse (CV = 17.93%). Bland¿Altman plots revealed wide limits of agreement between discrete IMU force signatures and force plate GRF. The 1D SPM outlined numerous significant (p < 0.01) differences between trunk- and tibia-located IMU-derived measures and force plate GRF traces in vertical and braking (horizontal) planes. The trunk- and tibia-mounted IMUs appeared to not represent the GRF experienced during pace bowling FFC when compared to a gold-standard force plate.

© 2017 National Strength and Conditioning Association. Lockie, RG, Moreno, MR, Orjalo, AJ, Lazar, A, Liu, TM, Stage, AA, Birmingham-Babauta, SA, Stokes, JJ, Giuliano, DV, Risso, FG, Davis, DL, and Callaghan, SJ. Relationships between height, arm length, and leg length on the mechanics of the conventional and high-handle hexagonal bar deadlift. J Strength Cond Res 32(11): 3011-3019, 2018-The study investigated relationships between arm length (AL) and leg length (LL) and conventional deadlift (CD) and high-handle hexagonal bar deadlift (HHBD) mechanics. Twenty-Three resistance-trained subjects (14 men and 9 women) completed a 1 repetition maximum CD and HHBD. A linear position transducer was used to measure lift distance and duration; peak and mean power, velocity, and force; time to peak power and velocity; and work. Right AL and LL were measured, and AL-To-LL ratio (AL:LL) was also calculated. Spearman's correlations (r; p = 0.05) computed relationships between anthropometry and deadlift mechanics separately for men and women. For the HHBD, greater height and LL related to greater lift distance and work (¿ = 0.54-0.68); a higher AL:LL related to time to peak power and velocity occurring sooner (¿ =-0.67 to 0.78). For the HHBD, greater height and LL related to greater lift distance and work; a higher AL:LL related to time to peak power and velocity occurring sooner in the lift (¿ = 0.54- 0.77). In women, greater height, AL, and LL related to a longer CD lift distance (¿ = 0.67-0.92). For the HHBD, greater height, AL, and LL related to a longer lift distance and greater mean velocity (¿ = 0.69-0.96). There was a negative relationship between AL and lift time (¿ = 20.83), which meant longer arms resulted in a lower HHBD lift time. Arm length may have influenced women more because of the fixed dimensions of the hexagonal bar. Coaches should be cognizant of potential differences in CD and HHBD work when performed by individuals of different body sizes.

© 2015 National Strength and Conditioning Association. The Functional Movement Screen (FMS) includes lower-body focused tests (deep squat [DS], hurdle step, in-line lunge) that could assist in identifying movement deficiencies affecting multidirectional sprinting and jumping, which are important qualities for team sports. However, the hypothesized relationship with athletic performance lacks supportive research. This study investigated relationships between the lower-body focused screens and overall FMS performance and multidirectional speed and jumping capabilities in team sport athletes. Twenty-two healthy men were assessed in the FMS, and multidirectional speed (0- to 5-m, 0- to 10-m, 0- to 20-m sprint intervals; 505 and between-leg turn differences, modified T-test and differences between initial movement to the left or right); and bilateral and unilateral multidirectional jumping (vertical [VJ], standing long [SLJ], and lateral jump) tests. Pearson's correlations (r) were used to calculate relationships between screening scores and performance tests (p = 0.05). After the determination of any screens relating to athletic performance, subjects were stratified into groups (3 = high-performing group; 2 = intermediate-performing group; 1 = low-performing group) to investigate movement compensations. A 1-way analysis of variance (p = 0.05) determined any between-group differences. There were few significant correlations. The DS did moderately correlate with betweenleg 505 difference (r = 20.423), and bilateral VJ (r = 20.428) and SLJ (r = 20.457). When stratified into groups according to DS score, high performers had a 13% greater SLJ when compared with intermediate performers, which was the only significant result. The FMS seems to have minimal capabilities for identifying movement deficiencies that could affect multidirectional speed and jumping in male 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's 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.

© Journal of Sports Science and Medicine. 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 differ-ences 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 signifi-cantly affect planned change-of-direction or reactive agility performance, and did not demonstrate large changes in activity of the muscle complex in healthy basketballers.

© 2014 Taylor & Francis. The cricket quick single has received minimal scientific analysis. This study investigated the acceleration kinematics of the non-striking batsmen during a quick single. A total of 20 cricketers completed 17.68-m sprints following three starts: standard (no cricket-specific equipment), static cricket (side-on start, bat held on crease) and rolling cricket (walking start, bat dragged through crease). Timing gates recorded 0¿5¿m and 0¿17.68¿m time. Participants wore leg guards and carried a bat during cricket-specific sprints. Joint and step kinematics were investigated through the first and second steps via motion analysis. A repeated measures analysis of variance determined significant (p <¿ 0.05) within-participant differences between conditions. The rolling cricket start resulted in faster 0¿5¿m and 0¿17.68¿m times, and a 12% longer first, and 8% longer second, step. For cricket-specific sprints, shoulder sagittal plane range of motion (ROM) and elbow extension decreased in the arm carrying the bat. In response to this reduced arm ROM, hip flexion decreased. There were no changes to hip extension. Shoulder and wrist frontal plane ROM, and wrist sagittal plane ROM, increased as a result of carrying the bat. The need for cricketers to use specialised equipment while completing a quick single resulted in specific acceleration kinematic alterations.

This study investigated the effects of a traditional speed and agility training program (TSA) and an enforced stopping program emphasizing deceleration (ESSA). Twenty college-aged team sport athletes (16 males, 4 females) were allocated into the training groups. Pretesting and posttesting included: 0-10, 0-20, 0-40 m sprint intervals, change-of-direction, and acceleration test (CODAT), T-test (multidirectional speed); vertical, standing broad, lateral, and drop jumps, medicine ball throw (power); Star Excursion Balance Test (posteromedial, medial, anteromedial reaches; dynamic stability); and concentric (240°·s-1) and eccentric (30°·s-1) knee extensor and flexor isokinetic testing (unilateral strength). Both groups completed a 6-week speed and agility program. The ESSA subjects decelerated to a stop within a specified distance in each drill. A repeated measures analysis of variance determined significant (p = 0.05) with in and between-group changes. Effect sizes (Cohen's d) were calculated. The TSA group improved all speed tests (d = 0.29-0.96), and most power tests (d = 0.57-1.10). The ESSA group improved the 40-m sprint, CODAT, T-test, and most power tests (d = 0.46-1.31) but did not significantly decrease 0-10 and 0-20 m times. The TSA group increased posteromedial and medial excursions (d = 0.97-1.89); the ESSA group increased medial excursions (d = 0.99-1.09). The ESSA group increased concentric knee extensor and flexor strength, but also increased between-leg knee flexor strength differences (d = 0.50-1.39). The loading associated with stopping can increase unilateral strength. Coaches should ensure deceleration drills allow for appropriate sprint distances before stopping, and athletes do not favor 1 leg for stopping after deceleration. © 2014 National Strength and Conditioning Association.

This study quantified the inter- and intra-test reliability of telemetric surface electromyography (EMG) and near infrared spectroscopy (NIRS) during resistance exercise. Twelve well-trained young men performed high-intensity back squat exercise (12 sets at 70-90% 1-repetition maximum) on two occasions, during which EMG and NIRS continuously monitored muscle activation and oxygenation of the thigh muscles. Intra-test reliability for EMG and NIRS variables was generally higher than inter-test reliability. EMG median frequency variables were generally more reliable than amplitude-based variables. The reliability of EMG measures was not related to the intensity or number of repetitions performed during the set. No notable differences were evident in the reliability of EMG between different agonist muscles. NIRS-derived measures of oxyhaemoglobin, deoxyhaemoglobin and tissue saturation index were generally more reliable during single-repetition sets than multiple-repetition sets at the same intensity. Tissue saturation index was the most reliable NIRS variable. Although the reliability of the EMG and NIRS measures varied across the exercise protocol, the precise causes of this variability are not yet understood. However, it is likely that biological variation during multi-joint isotonic resistance exercise may account for some of the variation in the observed results. © 2014 Elsevier Ltd.

Context: Research indicates that planned and reactive agility are different athletic skills. These skills have not been adequately assessed in male basketball players. Purpose: To define whether 10-m-sprint performance and planned and reactive agility measured by the Y-shaped agility test can discriminate between semiprofessional and amateur basketball players. Methods: Ten semiprofessional and 10 amateur basketball players completed 10-m sprints and planned- and reactive-agility tests. The Y-shaped agility test involved subjects sprinting 5 m through a trigger timing gate, followed by a 45° cut and 5-m sprint to the left or right through a target gate. In the planned condition, subjects knew the cut direction. For reactive trials, subjects visually scanned to find the illuminated gate. A 1-way analysis of variance (P < .05) determined between-groups differences. Data were pooled (N = 20) for a correlation analysis (P < .05). Results: The reactive tests differentiated between the groups; semiprofessional players were 6% faster for the reactive left (P = .036) and right (P = .029) cuts. The strongest correlations were between the 10-m sprints and planned-agility tests (r = .590-.860). The reactive left cut did not correlate with the planned tests. The reactive right cut moderately correlated with the 10-m sprint and planned right cut (r = .487-.485). Conclusions: The results reemphasized that planned and reactive agility are separate physical qualities. Reactive agility discriminated between the semiprofessional and amateur basketball players; planned agility did not. To distinguish between male basketball players of different ability levels, agility tests should include a perceptual and decision-making component. © 2014 Human Kinetics, Inc.

No research has analysed the influence of ankle muscle activity for joint mobility and stability on preferred directional cutting. Twelve basketballers completed the Y-Shaped agility test, requiring 45° cuts to the left or right, to assess planned and reactive cutting. In planned conditions, participants knew the cutting direction. In reactive conditions, participants responded to a randomly illuminated gate. Legs were defined as the outside (furthest from target gate) or inside (closest to target gate) cut legs. The preferred outside cutting leg was determined from the fastest planned cut. Electromyography measured peak normalised (against 10- meter sprint performance) activity of the tibialis anterior, peroneus longus (PL), peroneus brevis (PB), and soleus. Paired t-Tests (p > 0.05) compared preferred and non-preferred cutting legs; effect sizes (d) were calculated. There were no differences in muscle activity between the preferred and non-preferred legs in the planned (p = 0.218-0.828) or reactive (p = 0.092- 0.862) cuts. There were moderate effects for a 28% higher PL (d = 0.51), and 27% lower PB (d = 0.57) activity, for the reactive outside cut leg. Due to the synergistic nature of these muscles, there was likely no effect to agility. Irrespective of preferred cutting direction, ankle muscles respond similarly.

BACKGROUND: Team sport athletes require dynamic stability in unilateral activities for their sports, which necessitates some degree of knee flexion and extension strength. OBJECTIVE: To analyze the possible association of knee extension and flexion strength with dynamic stability, as measured by the Star Excursion Balance Test (SEBT). METHODS: Sixteen male team sport athletes completed the SEBT, which involves a series of unilateral squats with the subject maximally reaching with the other leg in eight directions. Knee muscle strength was measured isokinetically both concentrically (60°/s, 180°/s, 240°/s) and eccentrically (30°/s). Subjects were divided into better and lesser groups based on mean functional reach distance. A 1-way analysis of variance (p= 0.05) determined between-group differences in reach distances and relative torque. RESULTS: Subjects with better dynamic stability generated greater knee extensor torque concentrically at 180°/s for the right leg, and at all speeds for the left leg. The effects of knee strength were particularly noteworthy for the left leg, as subjects with better dynamic stability reached significantly further across all 8 directions. CONCLUSION: The results indicate that greater knee extensor strength may enhance unilateral dynamic stability in team sport athletes. © 2013 - IOS Press and the authors. All rights reserved.

Acceleration performance is important for field sport athletes that require a high level of repeat sprint ability. Although acceleration is widely trained for, there is little evidence outlining which kinematic factors delineate between good and poor acceleration. The aim of this study was to investigate the kinematic differences between individuals with fast and slow acceleration. Twenty field sport athletes were tested for sprint ability over the first three steps of a 15m sprint. Subjects were filmed at high speed to determine a range of lower body kinematic measures. For data analysis, subjects were then divided into relatively fast (n = 10) and slow (n = 10) groups based on their horizontal velocity. Groups were then compared across kinematic measures, including stride length and frequency, to determine whether they accounted for observed differences in sprint velocity. The results showed the fast group had significantly lower (~11-13%) left and right foot contact times (p < .05), and an increased stride frequency (~9%), as compared to the slow group. Knee extension was also significantly different between groups (p < .05). There was no difference found in stride length. It was concluded that those subjects who are relatively fast in early acceleration achieve this through reduced ground contact times resulting in an improved stride frequency. Training for improved acceleration should be directed towards using coaching instructions and drills that specifically train such movement adaptations. ©Journal of Sports Science and Medicine (2003).