Volker Nolte
Western University Canada, Kinesiology, Faculty Member
Research Interests:
Research Interests:
Total kinetic energy (TKE) was calculated for 28 Canadian national team Olympic rowers during training on water, comparing low-stroke rates (18-22 stroke/min) and high-stroke rates (32-40 stroke/min), using video analysis. Stroke duration... more
Total kinetic energy (TKE) was calculated for 28 Canadian national team Olympic rowers during training on water, comparing low-stroke rates (18-22 stroke/min) and high-stroke rates (32-40 stroke/min), using video analysis. Stroke duration was normalized to 100%, beginning and ending at the "catches", with the drive phase occurring first and recovery second. Two discrete points were identified during the stroke, both occurring when the fingers had the same horizontal position as the ankles (i.e., mid-drive and mid-recovery). The ratios of recovery-to-drive TKE at these points for the entire body at low and high-stroke rates were 0.36 +/- 0.34 and 1.26 +/- 0.54 respectively. Significant differences were found for the lower leg, upper arm and forearm segments, and within the female groups. Low-stroke rate is a typical training pace and high-stroke rate is analogous to a race pace. This study demonstrates that TKE production during recovery in a race was not replicated during training. While training at low-stroke rates is vital for technique refinement, this study stresses the importance of training appropriately for the energy expenditure during high-stroke rate recovery. This is commonly overlooked by coaches and athletes.
Research Interests: Mechanical Engineering, Mathematics, Performance, Motion Analysis, Medicine, and 15 morePhysical Medicine and Rehabilitation, Physical Therapy, Canada, Humans, Kinematics, Female, Male, Energy Expenditure, Adult, Kinetic Energy, Joints, Energy Transfer, Biomechanical Phenomena, Physical Endurance, and physical exertion
Research Interests:
The aim of this narrative review was to propose a deterministic model based on a review of previous research documenting the evidence for the associations between average kayak velocity and kinematic variables in sprint kayaking.... more
The aim of this narrative review was to propose a deterministic model based on a review of previous research documenting the evidence for the associations between average kayak velocity and kinematic variables in sprint kayaking. Literature was reviewed after searching electronic databases using key words 'kayak,' 'biomechanics,' 'velocity,' 'kinematics,' and 'performance.' Our kinematic deterministic model for sprint kayaking performance shows that the average kayak velocity is determined by kayak stroke displacement and stroke time. Stroke time had the strongest correlation with 200-m race time (r = 0.86, p < 0.001), and stroke rate (inversely proportional to stroke time) was strongly correlated with average horizontal velocity over two consecutive strokes at race pace (r = -0.83, p < 0.05). Increased stroke rate via decreased absolute water phase time and increased relative water phase time were indicative of more elite performance. There was no significant relationship between stroke displacement and velocity; however, a large decrease in stroke displacement may be detrimental to performance. Individual characteristics may be responsible for a paddlers' ability to achieve and sustain a given stroke rate. Coaches should theoretically focus interventions on increasing stroke rate while maintaining stroke displacement; however this hypothesis should be confirmed with prospective studies.
Research Interests:
Sprint kayaking stroke phase descriptions for biomechanical analysis of technique vary among kayaking literature, with inconsistencies not conducive for the advancement of biomechanics applied service or research. We aimed to provide a... more
Sprint kayaking stroke phase descriptions for biomechanical analysis of technique vary among kayaking literature, with inconsistencies not conducive for the advancement of biomechanics applied service or research. We aimed to provide a consistent basis for the categorisation and analysis of sprint kayak technique by proposing a clear observational model. Electronic databases were searched using key words kayak, sprint, technique, and biomechanics, with 20 sources reviewed. Nine phase-defining positions were identified within the kayak literature and were divided into three distinct types based on how positions were defined: water-contact-defined positions, paddle-shaft-defined positions, and body-defined positions. Videos of elite paddlers from multiple camera views were reviewed to determine the visibility of positions used to define phases. The water-contact-defined positions of catch, immersion, extraction, and release were visible from multiple camera views, therefore were suitable for practical use by coaches and researchers. Using these positions, phases and sub-phases were created for a new observational model. We recommend that kayaking data should be reported using single strokes and described using two phases: water and aerial. For more detailed analysis without disrupting the basic two-phase model, a four-sub-phase model consisting of entry, pull, exit, and aerial sub-phases should be used.
Research Interests:
The purpose of this study was to determine how sagittal kick symmetry in the underwater dolphin kick (UDK) between the downkick and upkick phases is related to UDK performance. Fifteen adult male competitive swimmers ranging from... more
The purpose of this study was to determine how sagittal kick symmetry in the underwater dolphin kick (UDK) between the downkick and upkick phases is related to UDK performance. Fifteen adult male competitive swimmers ranging from provincial to international level were filmed performing three trials each of maximum effort UDK over 15m using an underwater video camera. Video frames were manually digitized and each subjects' single fastest trial was evaluated for between-subject comparisons. Kinematic variables were calculated for each individual and Pearson product-moment correlations between the average horizontal centre of mass velocity (Vx) and all kinematic variables were calculated. Horizontal velocity during the downkick, horizontal velocity during the upkick, relative time spent in each phase, maximum chest flexion angle, maximum knee and ankle extension angles, the ratio of flexion/extension for chest, knee and ankle angles, and maximum vertical toe velocity during the upkick phase correlated significantly with Vx (p<0.05). The ratio of downkick vertical toe velocity/upkick vertical toe velocity was significantly negatively correlated with Vx (p<0.05). These results indicate the importance of kick symmetry for UDK performance, and indicate that performing the upkick phase well appears to be most important for UDK performance.
Research Interests: Engineering, Mathematics, Geodesy, Performance, Medicine, and 15 moreSwimming, Human Movement Science, Sports, Humans, Kinematics, Male, Acceleration, Adult, Athletic performance, Ankle, Motor Skills, Biomechanical Phenomena, Functional Laterality, Psychology and Cognitive Sciences, and Medical and Health Sciences
Research Interests:
Research Interests:
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Research Interests:
The analysis of rowing technique in training or competitive environments has been a challenge to biomechanists for some time now. Typically, two-dimensional assessments are carried out with fixed cameras mounted on-land next to a rowing... more
The analysis of rowing technique in training or competitive environments has been a challenge to biomechanists for some time now. Typically, two-dimensional assessments are carried out with fixed cameras mounted on-land next to a rowing course (Hay 1993) or by handheld cameras from an accompanying boat. Three-dimensional technique analysis were only presented for athletes rowing on an ergometer in a laboratory environment (Hofmijster et al. 2007). The purpose of this study was to develop and validate a system for three-dimensional kinematic analyses of on water rowing.
Research Interests:
The risk of falling increases in adults over the age of 65. A common barrier to take up physical activity in sedentary older adults is the fear of falls and injury. Experiences of masters athletes can provide insights into management of... more
The risk of falling increases in adults over the age of 65. A common barrier to take up physical activity in sedentary older adults is the fear of falls and injury. Experiences of masters athletes can provide insights into management of the risk for falling. The purpose of this phenomenological study was to explore the fall-risk experience of masters athletes actively competing in sport. Masters athletes over the age of 55 (n=22) described their experiences in semi-structured interviews. Data was analyzed through an interpretive-constructivist paradigm using inductive content analysis. Five dominant themes emerged: acceptance, learning, awareness, resilience, and self-fulfillment. Participants of our study reported an acceptance of the risk they take in sport for falls and injuries in their pursuits for self-fulfillment. Findings indicate that masters athletes accept the risk for falls and injuries in sport, find ways to adapt, and continue to compete because it is self-fulfilling. Sharing their experiences might inspire other older adults to get active as a rewarding means of remaining independent.
Research Interests:
The deflection of rowing oar shafts subjected to a static load was investigated. Two sets of sculling oars of different design stiffness were tested at three different lengths from 2.66 to 2.70 m. Loads up to 201 N were applied to the... more
The deflection of rowing oar shafts subjected to a static load was investigated. Two sets of sculling oars of different design stiffness were tested at three different lengths from 2.66 to 2.70 m. Loads up to 201 N were applied to the blade end of the oar shafts, and deflections were measured at six positions along the length of the shafts. The experimental results were compared with theoretical predictions obtained by modelling the oar shafts as homogenous end-loaded cantilever beams. The results show that the oar shafts are not uniform, in contradiction to the assumed model, but rather are most compliant near the sleeves and up to 80% stiffer towards the blades. The effect of oar shaft stiffness and length on the deflection angle at the blade end of the oar shaft was at most 1.18 ± 0.01°. The measured variation of stiffness along the shaft has implications for boat propulsion and rowing performance.
Research Interests:
The analysis of rowing technique in training or competitive environments has been a challenge to biomechanists for some time now. Typically, two-dimensional assessments are carried out with fixed cameras mounted on-land next to a rowing... more
The analysis of rowing technique in training or competitive environments has been a challenge to biomechanists for some time now. Typically, two-dimensional assessments are carried out with fixed cameras mounted on-land next to a rowing course (Hay 1993) or by handheld cameras from an accompanying boat. Three-dimensional technique analysis were only presented for athletes rowing on an ergometer in a laboratory environment (Hofmijster et al. 2007). The purpose of this study was to develop and validate a system for three-dimensional kinematic analyses of on water rowing.
Research Interests:
Research Interests:
The purpose of this investigation was to clarify the effects of blade design and oar length on performance in rowing. Biomechanical models and equations of motion were developed to identify the main forces that affect rowing performance.... more
The purpose of this investigation was to clarify the effects of blade design and oar length on performance in rowing. Biomechanical models and equations of motion were developed to identify the main forces that affect rowing performance. In addition, the mechanical connection between the propelling blade force and the force that the rower applies on the handle was established. On this basis it was found that the blade design and oar dimensions play a significant role on the rowing performance. While rowers have found empirically that larger and/or hydrodynamically more efficient blade shapes need to be rowed with shorter oars, this article explains this tendency from a biomechanical point of view. Based on the presented evidence, it can be concluded that shorter oars will allow rowers to improve the propelling forces without increasing the handle forces. These findings explain tendencies that started with the introduction of new blade shapes in 1991. A 2 x 2 factorial ANOVA was used...
Research Interests:
Reliability, variability, and validity of stroke rate measured via a Digitrainer accelerometer and GoPro 60 Hz video camera were determined. Six elite New Zealand kayakers (three males, three females) performed three trials of 300-m... more
Reliability, variability, and validity of stroke rate measured via a Digitrainer accelerometer and GoPro 60 Hz video camera were determined. Six elite New Zealand kayakers (three males, three females) performed three trials of 300-m sprints in a single kayak (K1) mounted with the Digitrainer and camera. Average individual within-trial reliability and between-trial reliability and variability were calculated using data from 40 strokes beginning at 200-m. Both Digitrainer and video showed good reliability (Mdiff% =5%; ES =0.6), and moderate variability (ICC <0.67; TE% <10%). There was good agreement between Digitrainer and video stroke rates (r=0.86, p=0.000), however the Digitrainer overestimated stroke rate by 4 ±5 spm. Both systems can assess relative change in stroke rate, however video should be used when valid stroke rates are required.
Research Interests:
The purpose of this study was to examine the feasibility of a method to measure the rolling of rowing shells during normal performance, and the comparison of balance patterns for several crews of different experience levels. One novice... more
The purpose of this study was to examine the feasibility of a method to measure the rolling of rowing shells during normal performance, and the comparison of balance patterns for several crews of different experience levels. One novice eight, a club four and two National team eights were analyzed during regular training routines. The balance measurement tool, a Silva Level, did not interfere with crew performance and the video analysis allowed accurate measurements to 0.5 deg at a sampling rate of 30 Hz. Although the study was designed as a pilot project, the results showed clear tendencies. Balance improved with the experience level of the crews. Boats seemed to be more balanced at higher stroke rates. Surprisingly, all crews appear to learn more to the same side, which could be connected with the rigging of the boats. Also, balance can be improved through appropriate training.
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Research Interests:
INTRODUCTION Quantifiable oar-shaft deformation can be detected using merely the naked eye during rowing competitions. Previous research [5] likewise showed a significant difference in rotational rates between the blade and oar-lock... more
INTRODUCTION Quantifiable oar-shaft deformation can be detected using merely the naked eye during rowing competitions. Previous research [5] likewise showed a significant difference in rotational rates between the blade and oar-lock during the drive phase. In theory, the force (N or kg x m/s2) applied at the oar handle is fully transmitted down the oar-shaft, through the blade, and into the water. This simplification is similar to the perfect efficiency in transferring power (ω or J/s) from the rower to the water. Oar manufacturers, such as Concept2 TM (Figure 1), categorize oar-shaft stiffness by measuring the amount of bending under a 10kg (98 N) load applied at 2.05m from the gate [4]. However, a universally recognized optimal oar-shaft stiffness level does not exist. Some researchers suggest rowing with a less stiff oar-shaft [3] while others advocate stiffer levels [1]. Therefore, the aim of the following study is to examine the relationship between experience level and oar-sha...
The PowerLine Boat Instrumentation System3 is comprised of instrumented oarlocks capable of measuring pin forces in the direction of boat travel and oarlock angles. The aim of this study was to determine the reliability and validity of... more
The PowerLine Boat Instrumentation System3 is comprised of instrumented oarlocks capable of measuring pin forces in the direction of boat travel and oarlock angles. The aim of this study was to determine the reliability and validity of the force and angle data from the PowerLine Boat Instrumentation System in a laboratory setting. Data were collected with the sculling oarlocks affixed to a horizontally aligned, stabilised wing rigger. For force analysis, signals were collected at 50 Hz from both the PowerLine system and a 1 kN load cell4 during 10 repetitions at a rate of approximately 30 repetitions per minute. For angular analysis, whilst recording with PowerLine, oarlocks were repositioned for a minimum of two seconds at known angles in a random order using an inclinometer accurate to one tenth of a degree over a range of -80° to +60°, in 20° increments. Linear regression analysis through the origin was used to compare the PowerLine values with known values from the load cell and...
ABSTRACT The aim was to evaluate place time consistency, and identify stroke rate trends required for success in K1 200-m kayaking. Race times and videos for each place in the A-finals of twelve World Cup and five World Championship... more
ABSTRACT The aim was to evaluate place time consistency, and identify stroke rate trends required for success in K1 200-m kayaking. Race times and videos for each place in the A-finals of twelve World Cup and five World Championship regattas held from 2006 to 2011 were collected from electronic databases. Quality broadcasted videos (24 Hz) of four men&#39;s and two women&#39;s World Championship K1 200-m races were retained for stroke rate analysis. Place time consistency was determined using a coefficient of variation (CV%). World Championship place time consistency was better (Men = 0.7 to 1.5%, Women = 0.7 to 1.7%) than World Cup place time consistency (Men = 2.7 to 6.9%, Women = 4.3 to 5.4%). World Championship medallists&#39; place time consistency did not exceed 1% for males and females. After the initial acceleration phase, all World Championship medallists showed a decline in stroke rate throughout the race (slope = -0.2 to -1.3 spm/s). World Championship medallists&#39; stroke rates averaged 158 ± 8.2 spm for males and 139 ± 5.8 spm for females. In conclusion, World Championship medal target times were consistent, and stroke rate and displacement ranges required to achieve these targets have been provided in a matrix.
Research Interests:
The risk of falling increases in adults over the age of 65. A common barrier to take up physical activity in sedentary older adults is the fear of falls and injury. Experiences of masters athletes can provide insights into management of... more
The risk of falling increases in adults over the age of 65. A common barrier to take up physical activity in sedentary older adults is the fear of falls and injury. Experiences of masters athletes can provide insights into management of the risk for falling. The purpose of this phenomenological study was to explore the fall-risk experience of masters athletes actively competing in sport. Masters athletes over the age of 55 (n=22) described their experiences in semi-structured interviews. Data was analyzed through an interpretive-constructivist paradigm using inductive content analysis. Five dominant themes emerged: acceptance, learning, awareness, resilience, and self-fulfillment. Participants of our study reported an acceptance of the risk they take in sport for falls and injuries in their pursuits for self-fulfillment. Findings indicate that masters athletes accept the risk for falls and injuries in sport, find ways to adapt, and continue to compete because it is self-fulfilling. ...
This study compared an all-out start (AO) to a constant power start strategy (CON) during a 6 min cycle performance on utilization of W ́ (energy above critical power (CP)), muscle deoxygenation (HHb), oxygen uptake (VO2) and performance... more
This study compared an all-out start (AO) to a constant power start strategy (CON) during a 6 min cycle performance on utilization of W ́ (energy above critical power (CP)), muscle deoxygenation (HHb), oxygen uptake (VO2) and performance in recreationally active individuals. The AO strategy was similar to that employed by rowers. Eight healthy males (age = 24 ± 3 y) completed a ramp test to fatigue (VO2peak = 4.42 ± 0.54 L∙min-1; peak power = 385 ± 35 W) and a 3-min all-out test to determine CP and the CON work rate. The AO strategy began with a 12 s sprint, followed by 258 s at 5%< CON. The CON work rate was calculated as (CP*W +(W ́J/360s) and performed for the initial 270 s of the ride. Both groups increased their effort, in 30 s intervals, over the last 90 s of each trial. The last 30 s was a sprint. Total W ́ utilized was higher during CON vs AO (18,109 ± 5,439J vs 13,754 ± 3,543 J, p<0.05). The HHb/VO2 ratio reflected a duration mismatch between O2 provision to O2 utilis...
Research Interests:
The deflection of rowing oar shafts subjected to a static load was investigated. Two sets of sculling oars of different design stiffness were tested at three different lengths from 2.66 to 2.70 m. Loads up to 201 N were applied to the... more
The deflection of rowing oar shafts subjected to a static load was investigated. Two sets of sculling oars of different design stiffness were tested at three different lengths from 2.66 to 2.70 m. Loads up to 201 N were applied to the blade end of the oar shafts, and deflections were measured at six positions along the length of the shafts. The experimental results were compared with theoretical predictions obtained by modelling the oar shafts as homogenous end-loaded cantilever beams. The results show that the oar shafts are not uniform, in contradiction to the assumed model, but rather are most compliant near the sleeves and up to 80% stiffer towards the blades. The effect of oar shaft stiffness and length on the deflection angle at the blade end of the oar shaft was at most 1.18 ± 0.01°. The measured variation of stiffness along the shaft has implications for boat propulsion and rowing performance.
Research Interests:
Research Interests:
Richer, SD, Nolte, VW, Bechard, DJ, and Belfry, GR. Effects of novel supramaximal interval training versus continuous training on performance in preconditioned collegiate, national, and international class rowers. J Strength Cond Res... more
Richer, SD, Nolte, VW, Bechard, DJ, and Belfry, GR. Effects of novel supramaximal interval training versus continuous training on performance in preconditioned collegiate, national, and international class rowers. J Strength Cond Res 30(6): 1752-1762, 2016-This investigation compared supramaximal oxygen uptake interval training with continuous training in collegiate, national, and international class rowers. It was hypothesized that 6 supramaximal intensity sessions over 11 days would increase power on selected power measures. After 8 weeks of training for a new season, 10 heavyweight and 6 lightweight rowers were randomized into 2 groups. A ramp test to limit of tolerance to determine peak aerobic power (6 females: 25 W·min; 10 males: 30 W·min) and an all-out 3-minute test to determine peak power, 60-second power, critical power, and work above critical power (W&amp;amp;#39;) were performed before and after training. A supramaximal training session consisted of 10 cycles of 10-second work (140% peak aerobic power):5-second recovery followed by 8 minutes of active recovery, and repeated 6 times. The continuous group performed predominantly moderate intensity (below lactate threshold) training. All training was performed on rowing ergometers. Critical power increased pre-to-post supramaximal (Δ7%) and continuous training (Δ9%), respectively (336 ± 59W to 360 ± 59W; 290 ± 73W to 316 ± 74W; p ≤ 0.05), whereas the mean power output from all performance measures increased only after supramaximal training (Δ7%) (464 ± 158W to 496 ± 184W; p ≤ 0.05). Testing also revealed decreased W&amp;amp;#39; (Δ21%) and 60-second power (Δ4%) pre-to-post continuous training only (p ≤ 0.05). No differences (p &amp;amp;gt; 0.05) in peak aerobic power or peak power were observed pre-to-post training in either group. In conclusion, after an 8-week preconditioning period, supramaximal interval training preserved anaerobic capacity compared with predominantly continuous training and elicited similar increases in critical power in rowers.
Research Interests:
The aim of this narrative review was to propose a deterministic model based on a review of previous research documenting the evidence for the associations between average kayak velocity and kinematic variables in sprint kayaking.... more
The aim of this narrative review was to propose a deterministic model based on a review of previous research documenting the evidence for the associations between average kayak velocity and kinematic variables in sprint kayaking. Literature was reviewed after searching electronic databases using key words &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;kayak,&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;biomechanics,&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;velocity,&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;kinematics,&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; and &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;performance.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; Our kinematic deterministic model for sprint kayaking performance shows that the average kayak velocity is determined by kayak stroke displacement and stroke time. Stroke time had the strongest correlation with 200-m race time (r = 0.86, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001), and stroke rate (inversely proportional to stroke time) was strongly correlated with average horizontal velocity over two consecutive strokes at race pace (r = -0.83, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). Increased stroke rate via decreased absolute water phase time and increased relative water phase time were indicative of more elite performance. There was no significant relationship between stroke displacement and velocity; however, a large decrease in stroke displacement may be detrimental to performance. Individual characteristics may be responsible for a paddlers&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; ability to achieve and sustain a given stroke rate. Coaches should theoretically focus interventions on increasing stroke rate while maintaining stroke displacement; however this hypothesis should be confirmed with prospective studies.
Research Interests:
ABSTRACT Reliability, variability, and validity of stroke rate measured via a Digitrainer accelerometer and GoPro 60 Hz video camera were determined. Six elite New Zealand kayakers (three males, three females) performed three trials of... more
ABSTRACT Reliability, variability, and validity of stroke rate measured via a Digitrainer accelerometer and GoPro 60 Hz video camera were determined. Six elite New Zealand kayakers (three males, three females) performed three trials of 300-m sprints in a single kayak (K1) mounted with the Digitrainer and camera. Average individual within-trial reliability and between-trial reliability and variability were calculated using data from 40 strokes beginning at 200-m. Both Digitrainer and video showed good reliability (Mdiff% ≤5%; ES ≤0.6), and moderate variability (ICC &lt;0.67; TE% &lt;10%). There was good agreement between Digitrainer and video stroke rates (r=0.86, p=0.000), however the Digitrainer overestimated stroke rate by 4 ±5 spm. Both systems can assess relative change in stroke rate, however video should be used when valid stroke rates are required.
ABSTRACT Reliability, variability, and validity of stroke rate measured via a Digitrainer accelerometer and GoPro 60 Hz video camera were determined. Six elite New Zealand kayakers (three males, three females) performed three trials of... more
ABSTRACT Reliability, variability, and validity of stroke rate measured via a Digitrainer accelerometer and GoPro 60 Hz video camera were determined. Six elite New Zealand kayakers (three males, three females) performed three trials of 300-m sprints in a single kayak (K1) mounted with the Digitrainer and camera. Average individual within-trial reliability and between-trial reliability and variability were calculated using data from 40 strokes beginning at 200-m. Both Digitrainer and video showed good reliability (Mdiff% ≤5%; ES ≤0.6), and moderate variability (ICC &lt;0.67; TE% &lt;10%). There was good agreement between Digitrainer and video stroke rates (r=0.86, p=0.000), however the Digitrainer overestimated stroke rate by 4 ±5 spm. Both systems can assess relative change in stroke rate, however video should be used when valid stroke rates are required.
Research Interests:
Sprint kayaking stroke phase descriptions for biomechanical analysis of technique vary among kayaking literature, with inconsistencies not conducive for the advancement of biomechanics applied service or research. We aimed to provide a... more
Sprint kayaking stroke phase descriptions for biomechanical analysis of technique vary among kayaking literature, with inconsistencies not conducive for the advancement of biomechanics applied service or research. We aimed to provide a consistent basis for the categorisation and analysis of sprint kayak technique by proposing a clear observational model. Electronic databases were searched using key words kayak, sprint, technique, and biomechanics, with 20 sources reviewed. Nine phase-defining positions were identified within the kayak literature and were divided into three distinct types based on how positions were defined: water-contact-defined positions, paddle-shaft-defined positions, and body-defined positions. Videos of elite paddlers from multiple camera views were reviewed to determine the visibility of positions used to define phases. The water-contact-defined positions of catch, immersion, extraction, and release were visible from multiple camera views, therefore were suitable for practical use by coaches and researchers. Using these positions, phases and sub-phases were created for a new observational model. We recommend that kayaking data should be reported using single strokes and described using two phases: water and aerial. For more detailed analysis without disrupting the basic two-phase model, a four-sub-phase model consisting of entry, pull, exit, and aerial sub-phases should be used.
Research Interests:
The aim of this narrative review was to propose a deterministic model based on a review of previous research documenting the evidence for the associations between average kayak velocity and kinematic variables in sprint kayaking.... more
The aim of this narrative review was to propose a deterministic model based on a review of previous research documenting the evidence for the associations between average kayak velocity and kinematic variables in sprint kayaking. Literature was reviewed after searching electronic databases using key words &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;kayak,&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;biomechanics,&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;velocity,&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;kinematics,&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; and &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;performance.&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; Our kinematic deterministic model for sprint kayaking performance shows that the average kayak velocity is determined by kayak stroke displacement and stroke time. Stroke time had the strongest correlation with 200-m race time (r = 0.86, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001), and stroke rate (inversely proportional to stroke time) was strongly correlated with average horizontal velocity over two consecutive strokes at race pace (r = -0.83, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). Increased stroke rate via decreased absolute water phase time and increased relative water phase time were indicative of more elite performance. There was no significant relationship between stroke displacement and velocity; however, a large decrease in stroke displacement may be detrimental to performance. Individual characteristics may be responsible for a paddlers&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; ability to achieve and sustain a given stroke rate. Coaches should theoretically focus interventions on increasing stroke rate while maintaining stroke displacement; however this hypothesis should be confirmed with prospective studies.
Research Interests:
Little research has evaluated the effects of drag suit training in swimming; these effects need to be explored further to optimize their use in training. For this 5-week training study, 18 subjects were divided evenly into 2 groups:... more
Little research has evaluated the effects of drag suit training in swimming; these effects need to be explored further to optimize their use in training. For this 5-week training study, 18 subjects were divided evenly into 2 groups: control group and drag suit-trained group. Both groups performed weekly training routines that included 3 sprint sets. These sprint sets were performed by both the groups; however, the drag suit training group wore the drag suit, and the control group wore their typical training attire. We evaluated the swimmers&amp;amp;amp;amp;#39; 50-m performance using a test set of six 50-m sprints on a 10-minute interval before and after the training program. The test set was performed twice (on 2 different days) where the swimmers were tested once in the drag suit and once in their regular training attire; the order of testing was randomized. Final time, stroke rate, and distance per stroke were collected. We observed that the drag suit-trained group exhibited a statistically significant decrease in distance per stoke while wearing the drag suit and the control group showed a significant increase in stroke rate and decrease in distance per stroke (in both suits). It is suggested to include some amounts of drag suit training in periods where swimming volume may decrease. Sets that are short in distance and performed at high intensity with sufficient rest to allow swimmers to maintain high stroke integrity should help athletes maintain techniques. We suggest incorporating the drag suit into the training regimen and should be considered a valuable resistive training device for swimming.
Research Interests:
The purpose of this study was to evaluate which measure of a drop jump (DJ) has the highest correlation with sprinting speed over 60 m. For use of comparison, maximal leg strengths in a front squat, countermovement jump, and squat jump... more
The purpose of this study was to evaluate which measure of a drop jump (DJ) has the highest correlation with sprinting speed over 60 m. For use of comparison, maximal leg strengths in a front squat, countermovement jump, and squat jump were also assessed. The subjects in the study were all high-caliber female university rugby players. Subjects did DJs from 0.12, 0.24, 0.36, 0.48, 0.60, 0.72, and 0.84 m. Jump height and reactive strength index (RSI) were calculated at each drop height. Pearson correlations were used to analyze the relationship between the strength and jumping measures with sprinting speed. The DJ height from 0.84 m had the highest negative correlation with 0- to 10-m split (r = -0.66), the 10- to 30-m split (r = -0.86) and 30- to 60-m split (r = -0.86). The use of RSI is questioned as a measurement of DJ performance. It is suggested that maximal height achieved in a DJ is the most important DJ measure. If it is desired to measure ground contact time, then it may be more useful to use a second test where the jump height for the athlete is set by having the athlete jump onto a box or touch a target overhead set at a standard height and measure the ground contact time with a switch mat or force plate.
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A common suggestion is that a predetermined level of maximal leg strength is required before drop jump (DJ) training can begin. This study sought to examine the relationship between maximal squat strength (1 repetition maximum [RM]) and... more
A common suggestion is that a predetermined level of maximal leg strength is required before drop jump (DJ) training can begin. This study sought to examine the relationship between maximal squat strength (1 repetition maximum [RM]) and DJ performance in 15 female rugby players (n = 15). The subjects were tested for 1RM, countermovement jump, squat jump, and DJs from 0.24, 0.36, 0.48, 0.60, 0.72, and 0.84 m. Jump height (JH) was calculated for all jumps and relative peak eccentric force, relative peak concentric force, ground contact time (GCT), and reactive strength index were also calculated for DJs. Pearson correlations were used to examine the relationship between 1RM relative to body mass (BM) (1RM/BM) and JHs, reactive strength index, and GCT during DJs. The subjects were placed in a high strength (HS) or low strength (LS) group depending on whether or not their 1RM/BM was &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;1 or &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1. The T-tests and 2-way analysis of variance (ANOVA) were used to compare the groups. A Fishers post hoc test was used for the ANOVA with significance set at p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05. A large correlation between JH and 1RM/BM was shown at the 0.84-m dropping height (r = 0.56). A significant overall difference was found between the HS and LS groups for DJ JH with a post hoc analysis revealing a significant difference at the 0.84-m drop height (p = 0.029). It is likely beneficial for female athletes to achieve high levels of maximal leg strength if they are going to use high (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;0.8-m) drop heights when performing DJs.
Research Interests:
The purpose of this study was to determine how sagittal kick symmetry in the underwater dolphin kick (UDK) between the downkick and upkick phases is related to UDK performance. Fifteen adult male competitive swimmers ranging from... more
The purpose of this study was to determine how sagittal kick symmetry in the underwater dolphin kick (UDK) between the downkick and upkick phases is related to UDK performance. Fifteen adult male competitive swimmers ranging from provincial to international level were filmed performing three trials each of maximum effort UDK over 15m using an underwater video camera. Video frames were manually digitized and each subjects&amp;amp;amp;amp;#39; single fastest trial was evaluated for between-subject comparisons. Kinematic variables were calculated for each individual and Pearson product-moment correlations between the average horizontal centre of mass velocity (Vx) and all kinematic variables were calculated. Horizontal velocity during the downkick, horizontal velocity during the upkick, relative time spent in each phase, maximum chest flexion angle, maximum knee and ankle extension angles, the ratio of flexion/extension for chest, knee and ankle angles, and maximum vertical toe velocity during the upkick phase correlated significantly with Vx (p&amp;amp;amp;amp;lt;0.05). The ratio of downkick vertical toe velocity/upkick vertical toe velocity was significantly negatively correlated with Vx (p&amp;amp;amp;amp;lt;0.05). These results indicate the importance of kick symmetry for UDK performance, and indicate that performing the upkick phase well appears to be most important for UDK performance.
Research Interests: Engineering, Performance, Swimming, Human Movement Science, Sports, and 13 moreHumans, Kinematics, Male, Young Adult, Acceleration, Adult, Athletic performance, Motor Skills, Biomechanical Phenomena, Functional Laterality, Competitive Behavior , Psychology and Cognitive Sciences, and Medical and Health Sciences
The PowerLine System includes instrumented rowing oarlocks, which measure athlete-applied forces during on-water rowing. Despite its international popularity, limited research has considered the quality engineering of the PowerLine... more
The PowerLine System includes instrumented rowing oarlocks, which measure athlete-applied forces during on-water rowing. Despite its international popularity, limited research has considered the quality engineering of the PowerLine system. Accordingly, the following research examined the convergent validity and test-retest reliability of the PowerLine force measurements. Unidirectional static forces of up to 431 N were applied to nine sweep and eight scull oarlocks over fifteen days of testing. The differences between the PowerLine force measurements and the known static forces were statistically analyzed. The PowerLine force measurements were consistent over the fifteen days of testing, but were 2.0 % ± 0.8 percentage points less than the quantities of the known applied forces. Although the differences between the experimental measurements and known applied forces corresponded with the manufacturer&#39;s specifications, calibration factors for each PowerLine oarlock were generated to correct for the minor discrepancies.
Research Interests:
Research Interests:
Total kinetic energy (TKE) was calculated for 28 Canadian national team Olympic rowers during training on water, comparing low-stroke rates (18-22 stroke/min) and high-stroke rates (32-40 stroke/min), using video analysis. Stroke duration... more
Total kinetic energy (TKE) was calculated for 28 Canadian national team Olympic rowers during training on water, comparing low-stroke rates (18-22 stroke/min) and high-stroke rates (32-40 stroke/min), using video analysis. Stroke duration was normalized to 100%, beginning and ending at the &amp;amp;amp;amp;amp;amp;amp;amp;quot;catches&amp;amp;amp;amp;amp;amp;amp;amp;quot;, with the drive phase occurring first and recovery second. Two discrete points were identified during the stroke, both occurring when the fingers had the same horizontal position as the ankles (i.e., mid-drive and mid-recovery). The ratios of recovery-to-drive TKE at these points for the entire body at low and high-stroke rates were 0.36 +/- 0.34 and 1.26 +/- 0.54 respectively. Significant differences were found for the lower leg, upper arm and forearm segments, and within the female groups. Low-stroke rate is a typical training pace and high-stroke rate is analogous to a race pace. This study demonstrates that TKE production during recovery in a race was not replicated during training. While training at low-stroke rates is vital for technique refinement, this study stresses the importance of training appropriately for the energy expenditure during high-stroke rate recovery. This is commonly overlooked by coaches and athletes.