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

A CASE STUDY OF A BEACH FLAGS START TECHNIQUE VARIATION IN ELITE SPRINTERS

Beach flags are a surf lifesaving event that involves a 20-meter sprint across sand. Sprinters begin in a prone position, facing the opposite direction to the intended sprint, before rising and turning to sprint and dive to capture a flag positioned in the sand. The typical start involves posterior movement away from the start line during the turn. Anecdotal evidence has suggested that beach flags sprinters can use variations to the start technique documented in the literature. Therefore, this research provided a case study of a start variation termed the pivot start. One male (age = 19 years; height = 1.74 m; mass = 66 kilograms), and one female (age = 23 years; height = 1.68 m; mass = 57 kilograms) elite sprinter were analyzed. A high-speed camera filmed the start. The analyzed data included: start time; hip and shoulder height during the turn; feet spacing; elbow, hip, knee, trunk lean, and trajectory angles at take-off, and descriptive statistics were derived. The analysis showed that the sprinters had no posterior movement behind the start line as they kept one leg on the start line, while the other leg was swung about the body so the sprinter rotated about the pivot leg. The rotatory start movements placed both sprinters into an effective, low body position for acceleration, indicated by trunk lean (~60°) and trajectory angle (~47°). These unique movement patterns should be trained accordingly for beach flags sprinters that use the pivot start

KINEMATIČKE RAZLIKE IZMEĐU UDARAČA I BACAČA NA PRIMERU QUICK SINGLE UDARCA U KRIKETU

The introduction of the shorter match formats in cricket (i.e. Twenty20 cricket) has led to a greater emphasis placed upon the successful performance of a quick single in match play. Therefore, the study aim was to investigate the kinematic variables between batsmen and fast bowlers when completing a quick single. Eighteen male cricketers completed 17.68-meter (m) sprints utilizing a match-specific start (walking start, bat dragged through crease and leg guards worn). Timing gates recorded 0-5 and 0-17.68 m time. Joint and step kinematics were analyzed through the first and second steps via motion analysis. Participants were split into batsmen and fast bowler groups based on their primary role within a team. A one-way analysis of variance determined significant (p< 0.05) differences between the batsmen and fast bowler groups. Effect sizes (Cohen’s d) were also calculated. Selected between-group kinematic differences were found. Fast bowlers had a significantly greater non-dominant elbow flexion, and second step swing leg ankle dorsi flexion. The requirements of fast bowling may have resulted in a cross-training effect, as increased range of motion in the bowling arm, and increased dorsi flexion on front and back foot landing, is associated with fast bowling technique. Nevertheless, there were no differences between the groups regarding quick single sprint performance. All cricket players should be proficient in the mechanisms of quick single sprint acceleration, regardless of their primary role in the team.Uvođenje skraćenih mečeva u kriketu (takozvani Twenty20 kriket) dovelo je do toga da pravilno izvođenje quick single udarca tokom meča dobije na značaju. Ovo istraživanje ima za cilj da analizira kinematičke razlike između udarača i bacača na primeru quick single udarca. Ukupno 18 igrača pretrčalo je 17.68 m sprintom, pri startu karakterističnom za kriket (hodanjem, provlačenjem drvene palice i uz upotrebu štitinika za noge). Prolazno vreme mereno je na 0-5 i 0-17.68 m. Kinematička analiza sprovedena je kod prvog i drugog koraka. Na osnovu primarnih pozicija u timu učesnici su podeljeni na grupu udarača i brzih bacača. Analiza varijanse utvrdila je da postoje statistički značajne razlike (p< 0.05) između grupa igrača. Izračunata je i vrednost Cohen’s d, i utvrđeno da postoje i određene međugrupne razlike. Kod brzih bacača utvrđena je značajno veća fleksija lakta ne-dominantne ruke, i dorsi fleksija u skočnom zglobu leve noge pri drugom koraku. Priprema brzih bacača možda je dodatno doprinela ovoj razlici, s obzirom na to da se uvećanje opsega pokreta ruke kojom se baca, i uvećanje dorsi fleksije stopala u iskoraku dovode u vezu sa tehnikom brzog bacanja. Ipak, nisu utvrđene razlike između grupa kada je u pitanju sprint. Svi igrači trebalo bi da budu upoznati sa mehanizmima sprinta kao što je ubrzanje, bez obzira na primarne pozicije u timu

Analysis of specific speed testing for cricketers

A characteristic of cricket sprints, which may require specific assessment, is that players carry a bat when running between the wickets. This study analyzed the relationships between general and specific cricket speed tests, which included 30-m sprint (0-to 5-, 0-to 10-, 0-to 30-m intervals; general); 505 change-of-direction speed test with left and right foot turns (general); 17.68-m sprint without and with (WB) a cricket bat (0-to 5-, 0-to 17.68-m intervals; specific); and run-a-three (specific). Seventeen male cricketers (age = 24.4 6 5.0 years; height = 1.84 6 0.06 m; mass = 86.9 6 13.9 kg) completed the tests, which were correlated (p , 0.05) to determine if they assessed different physical qualities. The subjects were also split into faster and slower groups based on the 17.68-m WB sprint time. A 1-way analysis of variance ascertained between-group differences in the tests (p , 0.05). The 17.68-m WB sprint correlated with the 0-to 10-and 0-to 30-m sprint intervals (r = 0.63-0.78) but not with the 0-to 5-m interval. The run-a-three correlated with the 505 and 17.68-m WB sprint (r = 0.62-0.90) but not with the 0-to 5-m interval. Poor relationships between the 0-to 5-m interval and cricket-specific tests may be because of the bat inclusion, as the sprints with a bat began with the subject ahead of the start line, and bat placed behind it. Furthermore, although the 17.68-m WB sprint and run-a-three differentiated faster and slower subjects, the 0-to 5-m sprint interval, and left foot 505, did not. The results indicated the necessity for cricket-specific speed testing. The 17.68-m WB sprint and run-a-three are potentially valuable tests for assessing cricket-specific speed. A bat should be incorporated when testing the running between the wickets ability

Acceleration kinematics in cricketers: implications for performance in the field

Cricket fielding often involves maximal acceleration to retrieve the ball. There has been no analysis of acceleration specific to cricketers, or for players who field primarily in the infield (closer to the pitch) or outfield (closer to the boundary). This study analyzed the first two steps of a 10-m sprint in experienced cricketers. Eighteen males (age = 24.06 ± 4.87 years; height = 1.81 ± 0.06 m; mass = 79.67 ± 10.37 kg) were defined as primarily infielders (n = 10) or outfielders (n = 8). Timing lights recorded 0-5 and 0-10 m time. Motion capture measured first and second step kinematics, including: step length; step frequency; contact time; shoulder motion; lead and rear arm elbow angle; drive leg hip and knee extension, and ankle plantar flexion; swing leg hip and knee flexion, and ankle dorsi flexion. A one-way analysis of variance (p < 0.05) determined between-group differences. Data was pooled for a Pearson’s correlation analysis (p < 0.05) to analyze kinematic relationships. There were no differences in sprint times, and few variables differentiated infielders and outfielders. Left shoulder range of motion related to second step length (r = 0.471). First step hip flexion correlated with both step lengths (r = 0.570-0.598), and frequencies (r = -0.504--0.606). First step knee flexion related to both step lengths (r = 0.528-0.682), and first step frequency (r = -0.669). First step ankle plantar flexion correlated with second step length (r = -0.692) and frequency (r = 0.726). Greater joint motion ranges related to longer steps. Cricketers display similar sprint kinematics regardless of fielding position, likely because players may field in the infield or outfield depending on match situation. Due to relationships with shoulder and leg motion, and the importance and trainability of step length, cricketers should target this variable to enhance acceleration

Ankle muscle function during preferred and non-preferred 45° directional cutting in semi-professional basketball players

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

Effects of sprint and plyometrics training on field sport acceleration technique

The mechanisms for speed performance improvement from sprint training and plyometrics training, especially relating to stance kinetics, require investigation in field sport athletes. This study determined the effects of sprint training and plyometrics training on 10-m sprint time (0–5, 5–10, and 0–10 m intervals), step kinematics (step length and frequency, contact and flight time), and stance kinetics (first, second, and last contact relative vertical [VF, VI], horizontal [HF, HI], and resultant [RF, RI] force and impulse; resultant ground reaction force angle [RF[theta]]; ratio of horizontal to resultant force [RatF]) during a 10-m sprint. Sixteen male field sport athletes were allocated into sprint training (ST) and plyometrics training (PT) groups according to 10-m sprint time; independent samples t-tests (p <= 0.05) indicated no between-group differences. Training involved 2 sessions per week for 6 weeks. A repeated measures analysis of variance (p <= 0.05) determined within- and between-subject differences. Both groups decreased 0–5 and 0–10 m time. The ST group increased step length by ~15%, which tended to be greater than step length gains for the PT group (~7%). The ST group reduced first and second contact RF[theta] and RatF, and second contact HF. Second contact HI decreased for both groups. Results indicated a higher post-training emphasis on VF production. Vertical force changes were more pronounced for the PT group for the last contact, who increased or maintained last contact VI, RF, and RI to a greater extent than the ST group. Sprint and plyometrics training can improve acceleration, primarily through increased step length and a greater emphasis on VF

Interaction Between Leg Muscle Performance and Sprint Acceleration Kinematics

This study investigated relationships between 10 m sprint acceleration, step kinematics (step length and frequency, contact and flight time), and leg muscle performance (power, stiffness, strength). Twenty-eight field sport athletes completed 10 m sprints that were timed and filmed. Velocity and step kinematics were measured for the 0-5, 5-10, and 0-10 m intervals to assess acceleration. Leg power was measured via countermovement jumps (CMJ), a fivebound test (5BT), and the reactive strength index (RSI) defined by 40 cm drop jumps. Leg stiffness was measured by bilateral and unilateral hopping. A three-repetition maximum squat determined strength. Pearson’s correlations and stepwise regression (p ≤ 0.05) determined velocity, step kinematics, and leg muscle performance relationships. CMJ height correlated with and predicted velocity in all intervals (r = 0.40-0.54). The 5BT (5-10 and 0-10 m intervals) and RSI (5-10 m interval) also related to velocity (r = 0.37-0.47). Leg stiffness did not correlate with acceleration kinematics. Greater leg strength related to and predicted lower 0-5 m flight times (r = -0.46 to -0.51), and a longer 0-10 m step length (r = 0.38). Although results supported research emphasizing the value of leg power and strength for acceleration, the correlations and predictive relationships (r2 = 0.14-0.29) tended to be low, which highlights the complex interaction between sprint technique and leg muscle performance. Nonetheless, given the established relationships between speed, leg power and strength, strength and conditioning coaches should ensure these qualities are expressed during acceleration in field sport athletes