Physical therapy in sport : official journal of the Association of Chartered Physiotherapists in Sports Medicine, Jan 28, 2018
To ascertain current injury surveillance and player education practices in Irish amateur rugby un... more To ascertain current injury surveillance and player education practices in Irish amateur rugby union. Cross-sectional survey. Amateur rugby clubs in Ireland. Medical professionals and rugby coaches of the top 58 amateur rugby clubs in Ireland. The survey investigated the current injury and training load monitoring practices in operation in Irish amateur rugby. It also explored whether player education sessions regarding injury prevention and concussion recognition and management were conducted in these clubs. Forty-four clubs completed the survey, giving an overall response rate of 76%. Ninety-one percent of the responding clubs monitored injuries. Sixty-four percent of these clubs operated return to play protocols for all injuries, while 36% operated return to play protocols for concussion only. Injury prevention education was conducted by 71% of these clubs and 82% educated players on concussion recognition and management. Implementing effective injury monitoring strategies in bot...
<b>Background</b>Unfamiliar exercises can cause a high level of exercise-induced musc... more <b>Background</b>Unfamiliar exercises can cause a high level of exercise-induced muscle damage (EIMD), particularly those that involve eccentric contractions. It is believed that the attenuation in muscular contractility caused by EIMD may compromise the quality of training, and thus appropriate recovery interventions need to be considered to minimise the level of EIMD. More recently, oral supplementation of branched-chain amino acid (BCAA) has been reported to alleviate the signs and symptoms of EIMD, and therefore accelerate recovery following strenuous training sessions. However, several studies have also reported no benefit of BCAA supplementation for EIMD recovery, with conflicting findings possibly due to variation in study designs. A systematic exploration of the literature that addresses these methodological limitations may provide the overall benefit of BCAA supplementation for recovery, although a thorough investigation has yet to be conducted. Thus, the purpose of this systematic review and meta-analysis will collate findings from various studies that have reported on the effects of BCAA supplementation on markers of EIMD.
Assessment of limb function asymmetry is of interest to practitioners due to its role in return t... more Assessment of limb function asymmetry is of interest to practitioners due to its role in return to play guidelines and reported links to injury. Dynamometry is one of the most commonly used methods of assessing muscle function, but the mode of contraction used is different to the stretch-shortening cycles experienced during real-life activities. The aim of this study was to compare measures of limb function asymmetry during isometric and stretch-shortening cycle tasks and investigate agreement between the methods. Different between-limb effect sizes were observed between limbs dependent on test used, with different ranges of asymmetry observed. Agreement between methods was very poor. These results show the importance of assessing asymmetry in a condition that is as similar as possible to the task of interest.
The aim of this study was to evaluate the effect of age on the use of arm swing in the vertical j... more The aim of this study was to evaluate the effect of age on the use of arm swing in the vertical jump. Counter-movement jumps with arms (CMJA) and without arms (CMJ) performed by 36 girls and 20 adult females were examined using force platform analysis. The data were analyzed to determine differences between groups and between types of jump. The analysis of the data indicated that the arm action increased the jump height in both groups, although the increase was greater in children than adults (22.6% and 18.7% respectively; P < .05). This difference in jump height was due to a combination of a greater increase of the height at take-off in children compared with adults (40.6% and 21.6% respectively; P < .05) with no differences in the increase of the flight height. This increase in height of take-off was accompanied by an increase in the distance of propulsion in CMJA compared with CMJ (0.25 m and 0.23 m respectively; P < .05). The results suggested that children take advanta...
The aim of this study was to assess the concurrent validity of the Optojump™ system (Microgate, B... more The aim of this study was to assess the concurrent validity of the Optojump™ system (Microgate, Bolzano, Italy) versus a force platform in the estimation of temporal and reactive strength measures. In two separate investigations, twenty physically active males performed double-leg and single-leg drop jumps from a box height of 0.3 m and a 10 s vertical bilateral hopping test. Contact time, flight time and total time (the sum of contact and flight time) were concurrently assessed during single and double-leg drop jumps and during hopping. Jump height, the reactive strength index and the reactive strength ratio were also calculated from contact time and flight time. Despite intraclass correlation coefficients (ICCs) for all variables being close to 1 (ICC > 0.975), a significant overestimation was found in contact time (0.005 ± 0.002 s) and underestimations in flight time (0.005 ± 0.003 s), the reactive strength index (0.04 ± 0.02 m·s-1) and the reactive strength ratio (0.07 ± 0.04...
This study examined the relationship of countermovement (CMJ), squat (SJ), and rebound jumps (RBJ... more This study examined the relationship of countermovement (CMJ), squat (SJ), and rebound jumps (RBJ), estimated 1RM back squat (SQ), contact time (CT) and Reactive Strength Index (RSI) for the RBJ to 30 m sprint time of sub-elite, semi-professional Rugby Union players. The results show that with the exception of SQ and CT, all variables were significantly (p < 0.001) correlated to each other (r > .575). The best determinant of predicting 30 m sprint time was RSI. The relationships of SJ, CMJ, and RBJ jump height and RSI to 30 m sprint time suggest that these rapid movements are all common in Rugby Union players. The results show that estimated 1 RM back squat has little influence on sprint performance. INTRODUCTION: Rugby is a demanding sport that requires high levels of speed strength and agility. Players need to exhibit explosive starts that can be translated to speed and maintained for both short (10 m) and extended (30 m) bursts. Fitness and performance in Rugby have often b...
The aim of this paper is to present a review on the role that movement variability plays in the a... more The aim of this paper is to present a review on the role that movement variability plays in the analysis of sports movement and in the monitoring of the athlete's skills. Movement variability has been traditionally considered an unwanted noise to be reduced, but recent studies have re-evaluated its role and have tried to understand whether it may contain important information about the neuro-musculo-skeletal organisation. Issues concerning both views of movement variability, different approaches for analysing it and future perspectives are discussed. Information regarding the nature of the movement variability is vital in the analysis of sports movements/motor skills and the way in which these movements are analysed and the movement variability subsequently quantified is dependent on the movement in question and the issues the researcher is trying to address. In dealing with a number of issues regarding movement variability, this paper has also raised a number of questions which are still to be addressed.
Journal of Strength and Conditioning Research, 2011
Comyns, TM, Harrison, AJ, and Hennessy, LK. An investigation into the recovery process of a maxim... more Comyns, TM, Harrison, AJ, and Hennessy, LK. An investigation into the recovery process of a maximum stretch-shortening cycle fatigue protocol on drop and rebound jumps. J Strength Cond Res 25(X): 000-000, 2011-The aim of this study was to investigate the recovery process of a maximal stretch-shortening cycle (SSC) fatigue workout on the biomechanical performance of drop jump (DJ) and rebound jump (RBJ) on a force sledge apparatus. Thirteen elite level rugby players performed sledge DJs and RBJs before and 15, 45, 120, and 300 seconds after a maximum SSC fatigue workout. Flight time, ground contact time (CT), peak force, reactive strength index (RSI), and leg-spring stiffness were the dependent variables. The DJ results showed that after 15 seconds recovery, there was a significant reduction in flight time (FT) (p , 0.01), RSI (p , 0.001), peak force (p , 0.01), and leg stiffness (p , 0.001). Similarly, the results for the RBJ indicated that the fatigue workout significantly reduced FT (p , 0.001), peak force (p , 0.01), RSI (p , 0.01), and significantly increased CT (p , 0.05) at the 15-second interval. The results also indicated a potentiation effect at the 300-second interval because of significant increases in RSI, peak force, and leg stiffness (p , 0.05) for the RBJ and significant increases in RSI (p , 0.05), peak force, and leg stiffness (p , 0.01) and a significant decrease in ground CT (p , 0.05) for the DJ. A maximal SSC fatigue workout had both an inhibiting and potentiating effect on DJ and RBJ performance depending on the recovery interval. The efficiency of the SSC function was reduced immediately after the cessation of the fatigue workout. A potentiation effect was evident for both jumps 300 seconds postfatigue.
Journal of Strength and Conditioning Research, 2010
Please provide the department name for affiliation 1. AU2) Please spell out RM in the sentence ''... more Please provide the department name for affiliation 1. AU2) Please spell out RM in the sentence ''Back squat 3RM.'' (also at the first occurrence in the main text). AU3) Please provide the city and country for the manufacturer Jenoptik. AU4) Please spell out SSC in the sentence ''In addition, Scott .'' AU5) Please note that according to the journal style, ''weightlifting'' can be used only when referring to ''competitive sport.'' Please check if this can be changed to ''resistance training'' or ''strength training'' when referring to exercise that involves lifting a weight. AU6) Please check whether CMJ can be spelled out in the sentence ''They examined the effect .'' AU7) Please check whether the clarity is okay: ''Caution should be given to this conclusion as the percentage increase is very small''. AU8) Please check if the edit to the sentence ''The dependent variables were time to 10-, 20-, and 30-m sprint....'' is correct. AU9) Please spell out ICC in the sentence ''The test-retest reliability of .'' AU10) Please spell out GLM in the sentence '' A GLM ANOVA was used.'' AU11) Please check the inline equation in the sentence ''This scale is based on f-values ..'' AU12) Please note that references in the list have been alphabetically ordered and corresponding changes are made to text citations as well. Please check if this is correct. Please note that Refs 8 and 25 have not been cited in the text. AU13) Please provide the journal name for Ref 15.
The Journal of Strength and Conditioning Research, 2006
Complex training research has indicated that 3-4 minutes may be an optimum intracomplex rest inte... more Complex training research has indicated that 3-4 minutes may be an optimum intracomplex rest interval. The purpose of this study was to determine if a heavy resistive exercise causes performance enhancement of a slow stretch-shortening cycle exercise and if there is an optimal rest interval. Eighteen subjects performed countermovement jumps before and after a 5RM back squat lifting protocol. This procedure was repeated 4 times over 2 days using rest intervals of 30 seconds, 2, 4 and 6 minutes. Flight time and peak ground reaction force were the dependent variables. All jumps were performed on a specially constructed sledge and force platform apparatus. Repeated measures ANOVA found a significant reduction in flight time at the 30 second and 6 minute interval (p < 0.05). No significant difference was found between men and women. Only the men showed an enhancement in jump performance after the 4 minute interval. The improvement window was different for each subject and an analysis of the greatest increase and decrease in flight time and peak ground reaction force was conducted, showing a significant decrease for men and women and a significant increase in flight time for men and peak ground reaction force for women. The results suggest that complex training can benefit and/ or inhibit countermovement jump performance depending on the rest interval. The individual determination of the intracomplex rest interval may be necessary in the practical setting.
The influence of range of motion versus application of force on vertical jump performance in prep... more The influence of range of motion versus application of force on vertical jump performance in prepubescent girls and adult females.
This study examined the kinematics of preferred and non-preferred instep kicking action in compet... more This study examined the kinematics of preferred and non-preferred instep kicking action in competitive soccer players. Using two gen-locked cameras, SHVS video data were obtained for seven players completing eight maximal effort instep kicks at a target with both feet. 3D kinematic analysis was carried out using Peak Motus to obtain joint angles of the standing and kicking legs and the frontal plane pelvic tilt angle. The results showed that when kicking with the preferred limb, the players' standing foot was closer to the ball and they used a larger frontal plane pelvic tilt angle and greater knee extension of the kicking leg at ball impact. There was greater variability in the kicking leg knee angle and this is consistent with Dynamical Systems Theory.
International Journal of Sports Science & Coaching, 2016
Coaches’ knowledge of drills and their specificity to sprint movement patterns and muscle activat... more Coaches’ knowledge of drills and their specificity to sprint movement patterns and muscle activations have become increasingly important. Drills are used to encourage the development of optimal movement and coordination. They are prescribed to help the athlete develop sprint technique, and it is generally assumed that the drills are the parts within a whole-part-whole learning strategy. Previous literature has suggested some drills may be questionable as they may not replicate the muscle activations or movement pattern of sprinting. A total of 209 coaches completed an online questionnaire, which examined coaches’ choice of drills; reasons for using each drill and reasons for changing drills used. The results were analysed using qualitative and quantitative methods. Results showed that coaches believed that drills are a vital part of training to improve performance but that they should be specific to sprinting technique.
The purpose of this study was to ascertain whether during childhood, the parameters for the range... more The purpose of this study was to ascertain whether during childhood, the parameters for the range of motion had more influence on jump height than parameters for application of force. Using force platform, an analysis was made of the countermovement jumps performed by 36 girls aged between 5 to 8 years old. Linear regression was used to analyze the data. The parameters for the range of motion accounted for 66% of the variance in maximum height jump, while application of force accounted for 12%. These results could indicate that the children can enhance their vertical jumping performance by increasing the range of motion rather than improving the ground reaction forces or their application. KEY WORDS: children, jump, range of movement, ground reaction force INTRODUCTION: The vertical jump is one of the most common skills in sports and games. The most common way to evaluate the vertical jump is by measuring the height jumped. Numerous studies show increases in jump height from childhood to adolescence (e.g. Malina, Bouchard & Bar-Or, 2004). During the fundamental movement phase of development (approximately 4 to 7 years), children acquire skills such as running, jumping, kicking, throwing and catching (Gallahue & Ozmun, 2005). While many studies explain how the increases in jump height during development are related to changes in anthropometry or muscle force (e.g. Taylor, Cohen, Voss & Sandercock, 2010), relatively few studies have focused on the effects of movement patterns (i.e. technique) in increasing jump height during development (Wang et al., 2004). The literature shows that there are no differences in the vertical jump for the coordination of movements between children and adults but there are differences in the amplitude and velocity of motion (Jensen et al., 1994). This includes differences in the magnitude of the angles, displacements, joint ranges or peak joint extension velocities used during the jump.
Schmidt's schema theory (1975) predicts that variable practice (VP) will outperform constant prac... more Schmidt's schema theory (1975) predicts that variable practice (VP) will outperform constant practice (CP). The implications of this for the teaching of skills such as the sprint start are that VP should allow equal or better learning to CP. The aim of this study was to examine the effect on novice subjects of practicing with varying block settings on the learning of the sprint start. A deterministic model of the spint start was derived using the guidelines of Hay and Reid (1982) to identify factor likely to affect performance. Measures of the factors were obtained using video and laser analysis. The affect of VP and CP on these factors was evaluated using a pre, post retention expermental design. Performance of the sprint start was compared between VP (n=6), CP (n=5), and Control (n=5) groups. Results showed no significant difference (p<0.05) between the VP and CP groups, as both groups improved to the same extent.
The purpose of this study was to examine the technical adaptations used by elite sprinters when r... more The purpose of this study was to examine the technical adaptations used by elite sprinters when running on sand dunes compared with running on a grass surface of similar gradient. Seven elite sprinters were videotaped while running at maximum effort up inclined sand and grass surfaces. Sagittal plane kinematic data were obtained using two video cameras placed on either side of the subjects. The video sequences were analysed using the Peak Motus. video analysis system. The results indicated that sand running caused reductions in running speed, stride rate, stride length and thigh range of motion. Ground contact time of the foot was increased and the relative timing of stride events was also disrupted while running on sand and this suggests a greater muscle loading effect compared with running on grass.
The current study examined the reliability of countermovement (CMJ), squat (SJ), and rebound jump... more The current study examined the reliability of countermovement (CMJ), squat (SJ), and rebound jumps (RBJ) to sprint and estimated 1RM back squat (SQ) of sub-elite Rugby Union players drawn from two teams of similar competitive level. Comparisons of mean performance on all tests were made via Student t-tests. The three trial reliability of jump height for the SJ, CMJ, RBJ, contact time (CT) and Reactive Strength Index for the RBJ, T-Test agility run (TA-Test), 30 and 36.58 m (40 yd) sprint times were estimated via ICC and ReANOVA. All variables displayed Average measures ICC ≥ .900; and except for the TA-Test, the three trials did not differ from each other. The performance of the two teams was found to be similar on all tests except the 30 m and 40 yd sprint tests. All the studied performance measures could be reliably assessed with one trial, except the TA-test.
Please confirm the given names (pink) and surnames (blue) of authors have been identified correct... more Please confirm the given names (pink) and surnames (blue) of authors have been identified correctly. AU1) Please note that as per style, the running head should contain only 50 characters; the running head introduced exceeds 50 characters. Please check. AU2) Please note that the affiliation provided has been treated as common for all the authors. Please check. And also provide city name for the affiliation. AU3) Please confirm if the conflicts of interest and funding statement is accurate. AU4) Please confirm if the author bios and headshots are accurate. AU5) Please check and confirm the edits made to the sentence "Several studies have." and correct if necessary. AU6) Please check the hierarchy of text section headings, and correct if necessary. AU7) Please update the references 11 and 27. AU8) Please note that the references have been renumbered both in text and in list so as to maintain alphabetical order in the reference list, as per the style. Please check.
The purpose of the present study was to compare lower limb alignment at initial ground contact be... more The purpose of the present study was to compare lower limb alignment at initial ground contact between groups with normal and abnormal hip rotation range of motion. Male (n=8) and female (n=8) subjects performed an maximal drop jump diagonal side cut task ten to the left and ten to the right. Lower limb alignment was assessed through knee angle, hip angle, ankle angle, thigh rotation and shank rotation at initial foot contact. One significant difference was reported between groups for the knee angle variable on the non dominant side. This indicates that the only the knee angle variable is affected by unbalanced hip rotation range of motion and on the non-dominant side. KEY WORDS: Anterior Cruciate Ligament, joint angles, limb dominance, segment rotations INTRODUCTION: Anterior cruciate ligament (ACL) injuries are well recognised as one of the most common and serious sports injuries with upwards of 250,000 ACL injuries in the United States each year (Boden et al. 2000). Seventy two p...
Physical therapy in sport : official journal of the Association of Chartered Physiotherapists in Sports Medicine, Jan 28, 2018
To ascertain current injury surveillance and player education practices in Irish amateur rugby un... more To ascertain current injury surveillance and player education practices in Irish amateur rugby union. Cross-sectional survey. Amateur rugby clubs in Ireland. Medical professionals and rugby coaches of the top 58 amateur rugby clubs in Ireland. The survey investigated the current injury and training load monitoring practices in operation in Irish amateur rugby. It also explored whether player education sessions regarding injury prevention and concussion recognition and management were conducted in these clubs. Forty-four clubs completed the survey, giving an overall response rate of 76%. Ninety-one percent of the responding clubs monitored injuries. Sixty-four percent of these clubs operated return to play protocols for all injuries, while 36% operated return to play protocols for concussion only. Injury prevention education was conducted by 71% of these clubs and 82% educated players on concussion recognition and management. Implementing effective injury monitoring strategies in bot...
<b>Background</b>Unfamiliar exercises can cause a high level of exercise-induced musc... more <b>Background</b>Unfamiliar exercises can cause a high level of exercise-induced muscle damage (EIMD), particularly those that involve eccentric contractions. It is believed that the attenuation in muscular contractility caused by EIMD may compromise the quality of training, and thus appropriate recovery interventions need to be considered to minimise the level of EIMD. More recently, oral supplementation of branched-chain amino acid (BCAA) has been reported to alleviate the signs and symptoms of EIMD, and therefore accelerate recovery following strenuous training sessions. However, several studies have also reported no benefit of BCAA supplementation for EIMD recovery, with conflicting findings possibly due to variation in study designs. A systematic exploration of the literature that addresses these methodological limitations may provide the overall benefit of BCAA supplementation for recovery, although a thorough investigation has yet to be conducted. Thus, the purpose of this systematic review and meta-analysis will collate findings from various studies that have reported on the effects of BCAA supplementation on markers of EIMD.
Assessment of limb function asymmetry is of interest to practitioners due to its role in return t... more Assessment of limb function asymmetry is of interest to practitioners due to its role in return to play guidelines and reported links to injury. Dynamometry is one of the most commonly used methods of assessing muscle function, but the mode of contraction used is different to the stretch-shortening cycles experienced during real-life activities. The aim of this study was to compare measures of limb function asymmetry during isometric and stretch-shortening cycle tasks and investigate agreement between the methods. Different between-limb effect sizes were observed between limbs dependent on test used, with different ranges of asymmetry observed. Agreement between methods was very poor. These results show the importance of assessing asymmetry in a condition that is as similar as possible to the task of interest.
The aim of this study was to evaluate the effect of age on the use of arm swing in the vertical j... more The aim of this study was to evaluate the effect of age on the use of arm swing in the vertical jump. Counter-movement jumps with arms (CMJA) and without arms (CMJ) performed by 36 girls and 20 adult females were examined using force platform analysis. The data were analyzed to determine differences between groups and between types of jump. The analysis of the data indicated that the arm action increased the jump height in both groups, although the increase was greater in children than adults (22.6% and 18.7% respectively; P < .05). This difference in jump height was due to a combination of a greater increase of the height at take-off in children compared with adults (40.6% and 21.6% respectively; P < .05) with no differences in the increase of the flight height. This increase in height of take-off was accompanied by an increase in the distance of propulsion in CMJA compared with CMJ (0.25 m and 0.23 m respectively; P < .05). The results suggested that children take advanta...
The aim of this study was to assess the concurrent validity of the Optojump™ system (Microgate, B... more The aim of this study was to assess the concurrent validity of the Optojump™ system (Microgate, Bolzano, Italy) versus a force platform in the estimation of temporal and reactive strength measures. In two separate investigations, twenty physically active males performed double-leg and single-leg drop jumps from a box height of 0.3 m and a 10 s vertical bilateral hopping test. Contact time, flight time and total time (the sum of contact and flight time) were concurrently assessed during single and double-leg drop jumps and during hopping. Jump height, the reactive strength index and the reactive strength ratio were also calculated from contact time and flight time. Despite intraclass correlation coefficients (ICCs) for all variables being close to 1 (ICC > 0.975), a significant overestimation was found in contact time (0.005 ± 0.002 s) and underestimations in flight time (0.005 ± 0.003 s), the reactive strength index (0.04 ± 0.02 m·s-1) and the reactive strength ratio (0.07 ± 0.04...
This study examined the relationship of countermovement (CMJ), squat (SJ), and rebound jumps (RBJ... more This study examined the relationship of countermovement (CMJ), squat (SJ), and rebound jumps (RBJ), estimated 1RM back squat (SQ), contact time (CT) and Reactive Strength Index (RSI) for the RBJ to 30 m sprint time of sub-elite, semi-professional Rugby Union players. The results show that with the exception of SQ and CT, all variables were significantly (p < 0.001) correlated to each other (r > .575). The best determinant of predicting 30 m sprint time was RSI. The relationships of SJ, CMJ, and RBJ jump height and RSI to 30 m sprint time suggest that these rapid movements are all common in Rugby Union players. The results show that estimated 1 RM back squat has little influence on sprint performance. INTRODUCTION: Rugby is a demanding sport that requires high levels of speed strength and agility. Players need to exhibit explosive starts that can be translated to speed and maintained for both short (10 m) and extended (30 m) bursts. Fitness and performance in Rugby have often b...
The aim of this paper is to present a review on the role that movement variability plays in the a... more The aim of this paper is to present a review on the role that movement variability plays in the analysis of sports movement and in the monitoring of the athlete's skills. Movement variability has been traditionally considered an unwanted noise to be reduced, but recent studies have re-evaluated its role and have tried to understand whether it may contain important information about the neuro-musculo-skeletal organisation. Issues concerning both views of movement variability, different approaches for analysing it and future perspectives are discussed. Information regarding the nature of the movement variability is vital in the analysis of sports movements/motor skills and the way in which these movements are analysed and the movement variability subsequently quantified is dependent on the movement in question and the issues the researcher is trying to address. In dealing with a number of issues regarding movement variability, this paper has also raised a number of questions which are still to be addressed.
Journal of Strength and Conditioning Research, 2011
Comyns, TM, Harrison, AJ, and Hennessy, LK. An investigation into the recovery process of a maxim... more Comyns, TM, Harrison, AJ, and Hennessy, LK. An investigation into the recovery process of a maximum stretch-shortening cycle fatigue protocol on drop and rebound jumps. J Strength Cond Res 25(X): 000-000, 2011-The aim of this study was to investigate the recovery process of a maximal stretch-shortening cycle (SSC) fatigue workout on the biomechanical performance of drop jump (DJ) and rebound jump (RBJ) on a force sledge apparatus. Thirteen elite level rugby players performed sledge DJs and RBJs before and 15, 45, 120, and 300 seconds after a maximum SSC fatigue workout. Flight time, ground contact time (CT), peak force, reactive strength index (RSI), and leg-spring stiffness were the dependent variables. The DJ results showed that after 15 seconds recovery, there was a significant reduction in flight time (FT) (p , 0.01), RSI (p , 0.001), peak force (p , 0.01), and leg stiffness (p , 0.001). Similarly, the results for the RBJ indicated that the fatigue workout significantly reduced FT (p , 0.001), peak force (p , 0.01), RSI (p , 0.01), and significantly increased CT (p , 0.05) at the 15-second interval. The results also indicated a potentiation effect at the 300-second interval because of significant increases in RSI, peak force, and leg stiffness (p , 0.05) for the RBJ and significant increases in RSI (p , 0.05), peak force, and leg stiffness (p , 0.01) and a significant decrease in ground CT (p , 0.05) for the DJ. A maximal SSC fatigue workout had both an inhibiting and potentiating effect on DJ and RBJ performance depending on the recovery interval. The efficiency of the SSC function was reduced immediately after the cessation of the fatigue workout. A potentiation effect was evident for both jumps 300 seconds postfatigue.
Journal of Strength and Conditioning Research, 2010
Please provide the department name for affiliation 1. AU2) Please spell out RM in the sentence ''... more Please provide the department name for affiliation 1. AU2) Please spell out RM in the sentence ''Back squat 3RM.'' (also at the first occurrence in the main text). AU3) Please provide the city and country for the manufacturer Jenoptik. AU4) Please spell out SSC in the sentence ''In addition, Scott .'' AU5) Please note that according to the journal style, ''weightlifting'' can be used only when referring to ''competitive sport.'' Please check if this can be changed to ''resistance training'' or ''strength training'' when referring to exercise that involves lifting a weight. AU6) Please check whether CMJ can be spelled out in the sentence ''They examined the effect .'' AU7) Please check whether the clarity is okay: ''Caution should be given to this conclusion as the percentage increase is very small''. AU8) Please check if the edit to the sentence ''The dependent variables were time to 10-, 20-, and 30-m sprint....'' is correct. AU9) Please spell out ICC in the sentence ''The test-retest reliability of .'' AU10) Please spell out GLM in the sentence '' A GLM ANOVA was used.'' AU11) Please check the inline equation in the sentence ''This scale is based on f-values ..'' AU12) Please note that references in the list have been alphabetically ordered and corresponding changes are made to text citations as well. Please check if this is correct. Please note that Refs 8 and 25 have not been cited in the text. AU13) Please provide the journal name for Ref 15.
The Journal of Strength and Conditioning Research, 2006
Complex training research has indicated that 3-4 minutes may be an optimum intracomplex rest inte... more Complex training research has indicated that 3-4 minutes may be an optimum intracomplex rest interval. The purpose of this study was to determine if a heavy resistive exercise causes performance enhancement of a slow stretch-shortening cycle exercise and if there is an optimal rest interval. Eighteen subjects performed countermovement jumps before and after a 5RM back squat lifting protocol. This procedure was repeated 4 times over 2 days using rest intervals of 30 seconds, 2, 4 and 6 minutes. Flight time and peak ground reaction force were the dependent variables. All jumps were performed on a specially constructed sledge and force platform apparatus. Repeated measures ANOVA found a significant reduction in flight time at the 30 second and 6 minute interval (p < 0.05). No significant difference was found between men and women. Only the men showed an enhancement in jump performance after the 4 minute interval. The improvement window was different for each subject and an analysis of the greatest increase and decrease in flight time and peak ground reaction force was conducted, showing a significant decrease for men and women and a significant increase in flight time for men and peak ground reaction force for women. The results suggest that complex training can benefit and/ or inhibit countermovement jump performance depending on the rest interval. The individual determination of the intracomplex rest interval may be necessary in the practical setting.
The influence of range of motion versus application of force on vertical jump performance in prep... more The influence of range of motion versus application of force on vertical jump performance in prepubescent girls and adult females.
This study examined the kinematics of preferred and non-preferred instep kicking action in compet... more This study examined the kinematics of preferred and non-preferred instep kicking action in competitive soccer players. Using two gen-locked cameras, SHVS video data were obtained for seven players completing eight maximal effort instep kicks at a target with both feet. 3D kinematic analysis was carried out using Peak Motus to obtain joint angles of the standing and kicking legs and the frontal plane pelvic tilt angle. The results showed that when kicking with the preferred limb, the players' standing foot was closer to the ball and they used a larger frontal plane pelvic tilt angle and greater knee extension of the kicking leg at ball impact. There was greater variability in the kicking leg knee angle and this is consistent with Dynamical Systems Theory.
International Journal of Sports Science & Coaching, 2016
Coaches’ knowledge of drills and their specificity to sprint movement patterns and muscle activat... more Coaches’ knowledge of drills and their specificity to sprint movement patterns and muscle activations have become increasingly important. Drills are used to encourage the development of optimal movement and coordination. They are prescribed to help the athlete develop sprint technique, and it is generally assumed that the drills are the parts within a whole-part-whole learning strategy. Previous literature has suggested some drills may be questionable as they may not replicate the muscle activations or movement pattern of sprinting. A total of 209 coaches completed an online questionnaire, which examined coaches’ choice of drills; reasons for using each drill and reasons for changing drills used. The results were analysed using qualitative and quantitative methods. Results showed that coaches believed that drills are a vital part of training to improve performance but that they should be specific to sprinting technique.
The purpose of this study was to ascertain whether during childhood, the parameters for the range... more The purpose of this study was to ascertain whether during childhood, the parameters for the range of motion had more influence on jump height than parameters for application of force. Using force platform, an analysis was made of the countermovement jumps performed by 36 girls aged between 5 to 8 years old. Linear regression was used to analyze the data. The parameters for the range of motion accounted for 66% of the variance in maximum height jump, while application of force accounted for 12%. These results could indicate that the children can enhance their vertical jumping performance by increasing the range of motion rather than improving the ground reaction forces or their application. KEY WORDS: children, jump, range of movement, ground reaction force INTRODUCTION: The vertical jump is one of the most common skills in sports and games. The most common way to evaluate the vertical jump is by measuring the height jumped. Numerous studies show increases in jump height from childhood to adolescence (e.g. Malina, Bouchard & Bar-Or, 2004). During the fundamental movement phase of development (approximately 4 to 7 years), children acquire skills such as running, jumping, kicking, throwing and catching (Gallahue & Ozmun, 2005). While many studies explain how the increases in jump height during development are related to changes in anthropometry or muscle force (e.g. Taylor, Cohen, Voss & Sandercock, 2010), relatively few studies have focused on the effects of movement patterns (i.e. technique) in increasing jump height during development (Wang et al., 2004). The literature shows that there are no differences in the vertical jump for the coordination of movements between children and adults but there are differences in the amplitude and velocity of motion (Jensen et al., 1994). This includes differences in the magnitude of the angles, displacements, joint ranges or peak joint extension velocities used during the jump.
Schmidt's schema theory (1975) predicts that variable practice (VP) will outperform constant prac... more Schmidt's schema theory (1975) predicts that variable practice (VP) will outperform constant practice (CP). The implications of this for the teaching of skills such as the sprint start are that VP should allow equal or better learning to CP. The aim of this study was to examine the effect on novice subjects of practicing with varying block settings on the learning of the sprint start. A deterministic model of the spint start was derived using the guidelines of Hay and Reid (1982) to identify factor likely to affect performance. Measures of the factors were obtained using video and laser analysis. The affect of VP and CP on these factors was evaluated using a pre, post retention expermental design. Performance of the sprint start was compared between VP (n=6), CP (n=5), and Control (n=5) groups. Results showed no significant difference (p<0.05) between the VP and CP groups, as both groups improved to the same extent.
The purpose of this study was to examine the technical adaptations used by elite sprinters when r... more The purpose of this study was to examine the technical adaptations used by elite sprinters when running on sand dunes compared with running on a grass surface of similar gradient. Seven elite sprinters were videotaped while running at maximum effort up inclined sand and grass surfaces. Sagittal plane kinematic data were obtained using two video cameras placed on either side of the subjects. The video sequences were analysed using the Peak Motus. video analysis system. The results indicated that sand running caused reductions in running speed, stride rate, stride length and thigh range of motion. Ground contact time of the foot was increased and the relative timing of stride events was also disrupted while running on sand and this suggests a greater muscle loading effect compared with running on grass.
The current study examined the reliability of countermovement (CMJ), squat (SJ), and rebound jump... more The current study examined the reliability of countermovement (CMJ), squat (SJ), and rebound jumps (RBJ) to sprint and estimated 1RM back squat (SQ) of sub-elite Rugby Union players drawn from two teams of similar competitive level. Comparisons of mean performance on all tests were made via Student t-tests. The three trial reliability of jump height for the SJ, CMJ, RBJ, contact time (CT) and Reactive Strength Index for the RBJ, T-Test agility run (TA-Test), 30 and 36.58 m (40 yd) sprint times were estimated via ICC and ReANOVA. All variables displayed Average measures ICC ≥ .900; and except for the TA-Test, the three trials did not differ from each other. The performance of the two teams was found to be similar on all tests except the 30 m and 40 yd sprint tests. All the studied performance measures could be reliably assessed with one trial, except the TA-test.
Please confirm the given names (pink) and surnames (blue) of authors have been identified correct... more Please confirm the given names (pink) and surnames (blue) of authors have been identified correctly. AU1) Please note that as per style, the running head should contain only 50 characters; the running head introduced exceeds 50 characters. Please check. AU2) Please note that the affiliation provided has been treated as common for all the authors. Please check. And also provide city name for the affiliation. AU3) Please confirm if the conflicts of interest and funding statement is accurate. AU4) Please confirm if the author bios and headshots are accurate. AU5) Please check and confirm the edits made to the sentence "Several studies have." and correct if necessary. AU6) Please check the hierarchy of text section headings, and correct if necessary. AU7) Please update the references 11 and 27. AU8) Please note that the references have been renumbered both in text and in list so as to maintain alphabetical order in the reference list, as per the style. Please check.
The purpose of the present study was to compare lower limb alignment at initial ground contact be... more The purpose of the present study was to compare lower limb alignment at initial ground contact between groups with normal and abnormal hip rotation range of motion. Male (n=8) and female (n=8) subjects performed an maximal drop jump diagonal side cut task ten to the left and ten to the right. Lower limb alignment was assessed through knee angle, hip angle, ankle angle, thigh rotation and shank rotation at initial foot contact. One significant difference was reported between groups for the knee angle variable on the non dominant side. This indicates that the only the knee angle variable is affected by unbalanced hip rotation range of motion and on the non-dominant side. KEY WORDS: Anterior Cruciate Ligament, joint angles, limb dominance, segment rotations INTRODUCTION: Anterior cruciate ligament (ACL) injuries are well recognised as one of the most common and serious sports injuries with upwards of 250,000 ACL injuries in the United States each year (Boden et al. 2000). Seventy two p...
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