Influence of foot-stretcher height on rowing technique and performance

Strength, technique, and coordination are crucial to rowing performance, but external interventions such as foot-stretcher set-up can fine-tune technique and optimise power output. For the same resultant force, raising the height of foot-stretchers on a rowing ergometer theoretically alters the orientation of the resultant force vector in favour of the horizontal component. This study modified foot-stretcher heights and examined their instantaneous effect on foot forces and rowing technique. Ten male participants rowed at four foot-stretcher heights on an ergometer that measured handle force, stroke length, and vertical and horizontal foot forces. Rowers were instrumented with motion sensors to measure ankle, knee, hip, and lumbar–pelvic kinematics. Key resultant effects of increased foot-stretcher heights included progressive reductions in horizontal foot force, stroke length, and pelvis range of motion. Raising foot-stretcher height did not increase the horizontal component of foot force as previously speculated. The reduced ability to anteriorly rotate the pelvis at the front of the stroke may be a key obstacle in gaining benefits from raised foot-stretcher heights. This study shows that small changes in athlete set-up can influence ergometer rowing technique, and rowers must individually fine-tune their foot-stretcher height to optimise power transfer through the rowing stroke on an ergometer.     

Asymmetry in elite rowers: effect of ergometer design and stroke rate

Between limb movement asymmetries and foot force production asymmetries are thought to be detrimental for both rower's performance and risk of injury, particularly when rowing frequently on ergometers. Several ergometers with different designs can be used by rowers as part of their indoor training. Hence, this study aimed to compare asymmetries in lower limb joint kinematics and foot force production with respect to ergometer design and rowing intensity. A new symmetry index was proposed to assess these asymmetries in elite rowers during a test on three ergometers. Additionally, the asymmetry in lower limb length was assessed to investigate its relationship with kinematic and kinetic asymmetries. Parameters describing medium (5–10%) or high (>10%) asymmetries were compared between rowing ergometers and intensities. Results indicated medium asymmetries for the ankle joint angle and hip–knee joint accelerations and high asymmetries for the resultant force and the ankle joint acceleration associated with a low inter-stroke variability. Kinetic asymmetry was neither correlated to kinematic asymmetry nor with lower limb length asymmetry. The use of a mobile ergometer led to higher joint acceleration asymmetries. Further studies are necessary to investigate the relation between these findings and muscular adaptations that may increase the risk of lower-back injury.     

Experimental laboratory apparatus to analyze kinematics and 3D kinetics in rowing

In order to quantify internal forces and articular moments, by the inverse dynamics method, specially at lumbar level, an experimental laboratory apparatus to analyze kinematics and 3D kinetics of rowers was developed. It comprised a 3D motion analysis system, a Type C Concept II ergometer, three force-plates, six axes and two miniature mono-dimensional force transducers. The apparatus was designed for each hand, with two miniature transducers integrated into new steel handles to measure the force developed by each hand. Furthermore, the apparatus was also designed for each foot. Two force platforms were placed under two new foot stretchers to measure force and moment developed by each foot. The ergometer also has a sliding seat under which was placed a miniature force platform. A study of the rowing movement of a regional level competition rower demonstrated the relevance of the data. This study was concerned with the 3D kinetics parameters expressed in the medio-lateral, anterio-posterior and vertical axes. Some obtained data are novel or rarely associated together and enable a better understanding of the rower movement.     

Lower limb reaction force asymmetry in rowers with and without a history of back injury

Back injury is common in rowers. Asymmetrical lower limb reaction force on the foot stretchers during rowing may compromise trunk biomechanics and lead to back injury. However, such a mechanism remains putative. Therefore, this study examined lower limb reaction force in experienced rowers with and without a history of back injury. Six rowers who suffered from back injury for more than one week in the past year and another 19 rowers who were never injured performed maximal exertion rowing on a fixed-head rowing machine for 30 strokes. Peak force, average and peak loading rate of the lower limb reaction force during the middle 10-stroke were recorded using strain-gauge transducers placed at the foot stretchers. Asymmetries and intra-limb variability were quantified as asymmetry indices and coefficients of variation, respectively. No significant asymmetry was observed in all selected kinetic parameters between the injured and healthy rowers (p = 0.448–0.722, Hedges' g = 0.162–0.310). Subgroup analyses also did not reveal any significant kinetic differences between injured and healthy scullers or sweepers (p = 0.194–0.855, Hedges' g = 0.203–0.518). Rowers with a history of back injury, regardless of the rowing types, did not demonstrate greater lower limb reaction force asymmetry when compared with healthy rowers.     

Incremental training intensities increases loads on the lower back of elite female rowers

Lumbar-pelvic kinematics change in response to increasing rowing stroke rates, but little is known about the effect of incremental stroke rates on changes in joint kinetics and their implications for injury. The purpose of this study was to quantify the effects of incremental rowing intensities on lower limb and lumbar-pelvic kinetics. Twelve female rowers performed an incremental test on a rowing ergometer. Kinematic data of rowers’ ankle, knee, hip and lumbar-pelvic joints, as well as external forces at the handle, seat and foot-stretchers of the rowing machine were recorded. Inter-segmental moments and forces were calculated using inverse dynamics and were compared across stroke rates using repeated measures ANOVA. Rowers exhibited increases in peak ankle and L5/S1 extensor moments, reductions in peak knee moments and no change in peak hip moments, with respect to stroke rate. Large shear and compressive forces were seen at L5/S1 and increased with stroke rate (P < 0.05). This coincided with increased levels of lumbar-pelvic flexion. High levels of lumbar-pelvic loading at higher stroke rates have implications with respect to injury and indicated that technique was declining, leading to increased lumbar-pelvic flexion. Such changes are not advantageous to performance and can potentially increase the risk of developing injuries.     

Relative shank to thigh length is associated with different mechanisms of power production during elite male ergometer rowing

The effect of anthropometric differences in shank to thigh length ratio upon timing and magnitude of joint power production during the drive phase of the rowing stroke was investigated in 14 elite male rowers. Rowers were tested on the RowPerfect ergometer which was instrumented at the handle and foot stretcher to measure force generation, and a nine segment inverse dynamics model used to calculate the rower's joint and overall power production. Rowers were divided into two groups according to relative shank thigh ratio. Time to half lumbar power generation was significantly earlier in shorter shank rowers (p = 0.028) compared to longer shank rowers, who showed no lumbar power generation during the same period of the drive phase. Rowers with a relatively shorter shank demonstrated earlier lumbar power generation during the drive phase resulting from restricted rotation of the pelvic segment requiring increased lumbar extension in these rowers. Earlier lumbar power generation and extension did not appear to directly affect performance measures of the short shank group, and so can be attributed to a technical adaptation developed to maximise rowing performance.     

Strapping rowers to their sliding seat improves performance during the start of ergometer rowing

Abstract

Rowers sit on a seat that slides relative to the boat/ergometer. If a rower lifts him or herself from this sliding seat at any time, the seat will move away from under them and the rowing action is disrupted. From a mechanical perspective, it is clear that the need for the rower to remain in contact with the sliding seat at all times imposes position-dependent constraints on the forces exerted at the oar handle and the footstretcher. Here we investigate if the mechanical power output during rowing, which is strongly related to these forces, might be improved if the contact with the sliding seat was of no concern to the rower. In particular, we examine if elimination of these constraints by strapping the rower to the sliding seat leads to an increase in performance during the start on a standard rowing ergometer. Eleven well-trained female rowers performed 5-stroke starts in normal and strapped conditions. Handle force, vertical seat force, footstretcher force, and handle kinematics were recorded, from which mechanical power and work output were calculated. Most of the relevant mechanical variables differed significantly between the normal and strapped conditions. Most importantly, mechanical power output (averaged over the 5-stroke start) in the strapped condition was 12% higher than in the normal condition. We conclude that strapping a rower's pelvis to the sliding seat allows more vigorous execution of the stroke phases, resulting in a substantial improvement in performance during the start of ergometer rowing.     

The effect of rowing to exhaustion on frontal plane angular changes in the lumbar spine of elite rowers

Abstract

Lumbar spine injury is common in rowers and examination of spinal kinematics may improve the understanding of this injury's prevalence. This study aimed to examine the range of frontal plane angular displacement (AD) in the lumbar spine at L3 during ergometer rowing and to investigate the effect of exhaustion on lumbar kinematics. Twelve elite male rowers completed an incremental test on a Concept 2 ergometer. Lumbar AD at L3 was measured continually throughout the rowing trial using a Spectrotilt Inclinometer and blood lactate was sampled at 3-minute intervals. AD of between 4.7° and 8.8° was recorded at L3. There was a significant increase in AD between the first and last stage of the test (mean increase = 4.1 ± 1.94°, 95% Confidence Interval [CI], 2.9 to 5.3°, t = 7.36, P = 0.000014). Incremental rise in AD was associated with an incremental rise in blood lactate but regression confirmed that only stroke rate was a significant predictor for increasing angle. Thus there is a statistically significant increase in frontal plane AD at L3 over the course of an incremental exercise test although it cannot be confirmed if this is as a result of exhaustion. The values of AD confirm that there is motion in the frontal plane in ergometer rowing.     

Reliability of power output during rowing changes with ergometer type and race distance

Coaches, sport scientists and researchers assess rowing performance on-water and on a variety of ergometers. Ergometers are frequently used because of the easier assessment environment. However, there is limited information on the ability of rowers to reproduce mean power or time-trial time when using different rowing ergometers (Concept II and RowPerfect) or completing tests over different distances (500 m versus 2000 m races). To test the efficacy of an intervention on a rower's ability to produce power, or to monitor that ability, it is essential to determine a reliable rowing performance test. The per cent standard error of measurement in performance (assessed by mean power and time-trial time) of fifteen national standard rowers was determined for five repeated 500 m and two repeated 2000 m races on a Concept II and RowPerfect ergometer. The per cent standard error of measurement (% SEM) in mean power between 5x500m races, regardless of gender, was 2.8% (95% confidence limits (CL)=2.3 to 3.4%) for the Concept II ergometer and 3.3% (95% CL=2.5 to 3.9%) for the RowPerfect ergometer (n = 15). Over 2000 m the per cent standard error of measurement in mean power was 1.3% (95% CL 0.9 to 2.9%) for the Concept II ergometer and 3.3% (95% CL 2.2 to 7.0%) for the RowPerfect ergometer The results highlight an increase in per cent standard error of the mean during performance races of less than 2000m on the Concept II ergometer, and performance races on the RowPerfect ergometer compared with the Concept II ergometer over 500 m and 2000 m. The most appropriate protocol for testing the influence of an intervention on the ability of a rower to produce power would be 2000 m races on a Concept II ergometer.     

The RowPerfect ergometer: a training aid for on-water single scull rowing

The purpose of this study was to compare rowing technique on the dynamic RowPerfect ergometer with a single scull. Eight national-level rowers performed on both the RowPerfect ergometer and in a single scull over 500 m, at rates of 24, 26, and 28 strokes/minute. Blade force and oar angle (on-water) and handle force and stroke length (on the ergometer) were measured. Both force and stroke angle/length were normalised from 0 to 100 (where 100 was the peak value). Body positions of the subjects at both the catch and finish of each of these rowing strokes were also compared for each stroke rate. The coefficient of multiple determination (CMD) was used to measure the consistency of force curves over a sample of five sequential strokes for each rower. Cross-correlations were performed between the left- and right-side on-water sculling force curves and a mean of these values with the ergometer curve for each rower. Stroke angle/length, which did not vary with rate, was similar for both forms of rowing. The CMDs showed a high consistency across the normalised strokes of each subject (approximately 0.98). Cross-correlation values of 0.91, 0.92, and 0.93 were recorded between the force curves from the ergometer and on-water trials for stroke rates of 24, 26, and 28 strokes/minute, respectively. The mean trunk, thigh and lower leg angles at the catch and finish of the stroke were also similar across the stroke rates as determined by t-tests. Results indicate that technique used on the RowPerfect ergometer was similar to that for on-water sculling, thus validating its use in off-water training.     

Rowing

The purpose of this study was to compare rowing technique on the dynamic RowPerfect ergometer with a single scull. Eight national‐level rowers performed on both the RowPerfect ergometer and in a single scull over 500 m, at rates of 24, 26, and 28 strokes/minute. Blade force and oar angle (on‐water) and handle force and stroke length (on the ergometer) were measured. Both force and stroke angle/length were normalised from 0 to 100 (where 100 was the peak value). Body positions of the subjects at both the catch and finish of each of these rowing strokes were also compared for each stroke rate. The coefficient of multiple determination (CMD) was used to measure the consistency of force curves over a sample of five sequential strokes for each rower. Cross‐correlations were performed between the left‐ and right‐ side on‐water sculling force curves and a mean of these values with the ergometer curve for each rower. Stroke angle/length, which did not vary with rate, was similar for both forms of rowing. The CMDs showed a high consistency across the normalised strokes of each subject (≈0.98). Cross‐correlation values of 0.91, 0.92, and 0.93 were recorded between the force curves from the ergometer and on‐water trials for stroke rates of 24, 26, and 28 strokes/minute, respectively. The mean trunk, thigh and lower leg angles at the catch and finish of the stroke were also similar across the stroke rates as determined by t‐tests. Results indicate that technique used on the RowPerfect ergometer was similar to that for on‐water sculling, thus validating its use in off‐water training.     

Book Review

Abstract

The mechanical responses (i.e. external contact forces and external power) of 25 elite rowers to a race-pace rowing protocol were investigated on the traditional fixed stretcher mechanism and the more recently introduced free-floating stretcher mechanism rowing ergometers. Using a Rowperfect rowing ergometer for both conditions, external contact forces at the handle, stretcher and sliding seat, as well as the displacements of the handle and stretcher, were recorded. The external power was calculated as the product of the force and velocity data from both the handle and stretcher. Significant differences (P < 0.05) between the two conditions for each mechanical parameter were observed. The fixed condition showed larger maximum values for forces and external power and average power throughout the rowing cycle. Moreover, rowing with the fixed mechanism generated higher inertial forces during the transition between the propulsion and recovery phases, especially at the catch of the cycle. The results suggest that: (i) muscular coordination may differ according to the stretcher mechanism used, which could have an impact on the physiological adaptations of muscles; and (ii) the free-floating mechanism may induce lower catch and maximum values for net joint forces and net joint moments that could decrease the risk of injury.     

Device for on-the-water measurement of rowing output

All those who compete in the sport of rowing have used the land rowing machine, Ergometer (commonly called the ‘erg’), manufactured by Concept II (Morrisville, Vermont, USA). Ergon is the Greek word for work, hence the Ergometer measures work. Rowers are commonly ranked according to their ‘erg score.’ The fault in this ranking is that the land Ergometer cannot account for many of the important technical aspects associated with rowing on the water. The goals of this project were to (1) develop a system for on-the-water measurement of work during rowing and then (2) demonstrate the potential of such a system to quantify performance and improve rowing technique. To achieve these goals, force was measured using strain gauges glued to the shaft of the rowing oar and angular displacement was measured using a potentiometer. The force and displacement measurements were sent to a microcontroller, which calculated the total work done in a particular stroke, as well as other parameters, and displayed the values to the rower. The parameters were used to evaluate the performance of three collegiate rowers on the water. The data were also used to plot force profiles, which were reviewed with each rower and the coach to illustrate the rowers’ habits and facilitate improving technique. One rower was ‘tutored’ with the device through five on-the-water practices, after which his force profiles and parameter values demonstrated significant improvement. The device not only provided a standard to which all rowers were compared on the water, but also supplied the rowers with important information on technical aspects of their strokes and pacing themselves.     

Comparing para-rowing set-ups on an ergometer using kinematic movement patterns of able-bodied rowers

While numerous studies have investigated the biomechanics of able-bodied rowing, few studies have been completed with para-rowing set-ups. The purpose of this research was to provide benchmark data for handle kinetics and joint kinematics for able-bodied athletes rowing in para- rowing set-ups on an indoor ergometer. Able-bodied varsity rowers performed maximal trials in three para-rowing set-ups; Legs, Trunk and Arms (LTA), Trunk and Arms (TA) and Arms and Shoulders (AS) rowing. The handle force kinetics of the LTA stroke were comparable to the values for able-bodied literature. Lumbar flexion at the catch, extension at the finish and total range of motion were, however, greater than values in the literature for able-bodied athletes in the LTA set-up. Additionally, rowers in TA and AS set-ups utilised more extreme ranges of motion for lumbar flexion, elbow flexion and shoulder abduction than the LTA set-up. This study provides the first biomechanical values of the para-rowing strokes for researchers, coaches and athletes to use while promoting the safest training programmes possible for para-rowing.     

Improved determination of mechanical power output in rowing: Experimental results

In rowing, mechanical power output is a key parameter for biophysical analyses and performance monitoring and should therefore be measured accurately. It is common practice to estimate on-water power output as the time average of the dot product of the moment of the handle force relative to the oar pin and the oar angular velocity. In a theoretical analysis we have recently shown that this measure differs from the true power output by an amount that equals the mean of the rower’s mass multiplied by the rower’s center of mass acceleration and the velocity of the boat. In this study we investigated the difference between a rower’s power output calculated using the common proxy and the true power output under different rowing conditions. Nine rowers participated in an on-water experiment consisting of 7 trials in a single scull. Stroke rate, technique and forces applied to the oar were varied. On average, rowers’ power output was underestimated with 12.3% when determined using the common proxy. Variations between rowers and rowing conditions were small (SD = 1.1%) and mostly due to differences in stroke rate. To analyze and monitor rowing performance accurately, a correction of the determination of rowers’ on-water power output is therefore required.     

Muscle morphology of the vastus lateralis is strongly related to ergometer performance,sprint capacity and endurance capacity in Olympic rowers

Rowers need to combine high sprint and endurance capacities. Muscle morphology largely explains muscle power generating capacity, however, little is known on how muscle morphology relates to rowing performance measures. The aim was to determine how muscle morphology of the vastus lateralis relates to rowing ergometer performance, sprint and endurance capacity of Olympic rowers. Eighteen rowers (12♂, 6♀, who competed at 2016 Olympics) performed an incremental rowing test to obtain maximal oxygen consumption, reflecting endurance capacity. Sprint capacity was assessed by Wingate cycling peak power. M. vastus lateralis morphology (volume, physiological cross-sectional area, fascicle length and pennation angle) was derived from 3-dimensional ultrasound imaging. Thirteen rowers (7♂, 6♀) completed a 2000-m rowing ergometer time trial. Muscle volume largely explained variance in 2000-m rowing performance (R² = 0.85), maximal oxygen consumption (R² = 0.65), and Wingate peak power (R² = 0.82). When normalized for differences in body size, maximal oxygen consumption and Wingate peak power were negatively related in males (r = ?0.94). Fascicle length, not physiological cross-sectional area, attributed to normalized peak power. In conclusion, vastus lateralis volume largely explains variance in rowing ergometer performance, sprint and endurance capacity. For a high normalized sprint capacity, athletes may benefit from long fascicles rather than a large physiological cross-sectional area.     

Fixed versus free-floating stretcher mechanism in rowing ergometers: mechanical aspects

The mechanical responses (i.e. external contact forces and external power) of 25 elite rowers to a race-pace rowing protocol were investigated on the traditional fixed stretcher mechanism and the more recently introduced free-floating stretcher mechanism rowing ergometers. Using a Rowperfect rowing ergometer for both conditions, external contact forces at the handle, stretcher and sliding seat, as well as the displacements of the handle and stretcher, were recorded. The external power was calculated as the product of the force and velocity data from both the handle and stretcher. Significant differences (P < 0.05) between the two conditions for each mechanical parameter were observed. The fixed condition showed larger maximum values for forces and external power and average power throughout the rowing cycle. Moreover, rowing with the fixed mechanism generated higher inertial forces during the transition between the propulsion and recovery phases, especially at the catch of the cycle. The results suggest that: (i) muscular coordination may differ according to the stretcher mechanism used, which could have an impact on the physiological adaptations of muscles; and (ii) the free-floating mechanism may induce lower catch and maximum values for net joint forces and net joint moments that could decrease the risk of injury.     

Dynamic post-activation potentiation protocol improves rowing performance in experienced female rowers

ABSTRACT

Post-activation potentiation likely acutely improves power-based performance; however, few studies have demonstrated improved endurance performance. Forty collegiate female rowers performed isometric potentiating (ISO), dynamic potentiating (DYN) and control (CON) warm-up protocols on a rowing ergometer, followed by a three-minute all-out test to evaluate their total distance, peak power, mean power, critical power, anaerobic working capacity (W’) and stroke rate. Fifteen-second splits were also analysed. ISO consisted of 5 × 5-second static muscle actions with the ergometer handle rendered immovable with a nylon strap, while DYN consisted of 2 × 10-second all-out rowing bouts, separated by a 2-minute rest interval. The participants were divided into high and low experience groups by median experience level (3.75 years) for statistical analysis. Significant differences (DYN > CON; p < 0.05) were found for distance (+5.6 m), mean power (+5.9 W) and W’ (+1561.6 J) for more experienced rowers (n = 19) and no differences for less experienced rowers (n = 18). Mean power in DYN was significantly greater than CON and ISO in the 15–30, 30–45, 45–60 and 60–75 second intervals independent of experience level. These results suggest that DYN may benefit experienced female rowers and that these strategies might benefit a greater power output over shorter distances regardless of experience.