A kinematic comparison of on-ergometer and on-water kayaking

One-dimension statistical parametric mapping in lower limb biomechanical analysis: A systematic scoping review

BACKGROUND

Biomechanics significantly impacts sports performance and injury prevention. Traditional methods like discrete point analysis simplify continuous kinetic and kinematic data, while one-dimensional Statistical Parametric Mapping (spm1d) evaluates entire movement curves. Nevertheless, spm1d's application in sports and injury research is limited. As no systematic review exists, we conducted a scoping systematic review, synthesizing the current applications of spm1d across various populations, activities, and injuries. This review concludes by identifying gaps in the literature and suggesting areas for future research.

RESEARCH QUESTION

What research exists using spm1d in sports biomechanics, focusing on the lower limbs, in what populations, and what are the current research gaps?

METHODS

We searched PubMed, Embase, Web of Science, and ProQuest databases for the following search string: "(((knee) OR (hip)) OR (ankle)) OR (foot) OR (feet) AND (statistical parametric mapping)". English peer-reviewed studies assessing lower limb kinetics or kinematics in different sports or sports-related injuries were included. Reviews, meta-analyses, conference abstracts, and grey literature were excluded.

RESULTS

Our search yielded 165 papers published since 2012. Among these, 112 examined healthy individuals (67 %), and 53 focused on injured populations (33 %). Running (n = 45), cutting (n = 25), and jumping/landing (n = 18) were the most common activities. The predominant injuries were anterior cruciate ligament rupture (n = 21), chronic ankle instability (n = 18), and hip-related pain (n = 9). The main research gaps included the unbalanced populations, underrepresentation of common sports and sport-related injuries, gender inequality, a lack of studies in non-laboratory settings, a lack of studies on varied sports gear, and a lack of reporting standardization.

SIGNIFICANCE

This review spotlights crucial gaps in spm1d research within sports biomechanics. Key issues include a lack of studies beyond laboratory settings, underrepresentation of various sports and injuries, and gender disparities in research populations. Addressing these gaps can significantly enhance the application of spm1d in sports performance, injury analysis, and rehabilitation.

Development of a video camera-type kayak motion capture system to measure water kayaking

Background

In kayaking, trunk motion is one of the important factors that prevent injury and improve performance. Kinematic studies in kayaking have been reported in laboratory settings using paddling simulators and ergometers. However, such studies do not reflect kayaking on water, the actual competitive environment. Therefore, we developed a video camera-type kayak motion capture system (KMCS) wherein action cameras were fixed to a kayak to capture images of markers attached to an athlete's body. This study aimed to compare the kinematic data between KMCS and an optical motion capture system (OMCS) in kayaking and to determine the accuracy of the KMCS analysis.

Methods

In a competition, five elite junior female kayak athletes performed kayak paddling under the unloaded condition using a kayak. The kayak was secured using a tri-folding bench and a towel, and twenty strokes were recorded during maximal paddling. One stroke was defined as the period from right catch to left catch, and the first six strokes were used to evaluate the accuracy. Trunk angles (tilting, turning, and rotation) were examined with the simultaneous use of KMCS and OMCS, and the differences between these systems were evaluated. To ensure reliability, intraclass correlation coefficient (ICC; a two-way mixed model for absolute agreement) was calculated for each angle. Furthermore, Bland-Altman analysis was performed to understand the agreement between the two systems.

Results

Root mean square errors (RMSEs) were 1.42° and 3.94° for turning and rotation, respectively, and mean absolute errors (MAEs) were 1.08° and 3.00° for turning and rotation, respectively. The RMSE and MAE for tilting were 2.43° and 1.76°, respectively, which indicated that the validity was comparable to that of other angles. However, the range of motion in tilting was lower than that in turning and rotation. Bland-Altman analysis showed good agreement in the total range of motion, with mean bias values of -0.84°, -0.07°, and -0.41° for tilting, turning, and rotation, respectively. The ICCs for tilting, turning, and rotation were 0.966, 0.985, and 0.973, respectively, and showed excellent reliability.

Conclusions

The newly developed KMCS effectively measured the trunk motion with good accuracy in kayaking. In future studies, we intend to use KMCS to measure kayaking on water and collect data for performance improvement and injury prevention.

Enhanced Maximal Upper-Body Strength Increases Performance in Sprint Kayaking

ABSTRACT

Kristiansen, M, Sydow Krogh Pedersen, A-M, Sandvej, G, Jørgensen, P, Jakobsen, JV, de Zee, M, Hansen, EA, and Klitgaard, KK. Enhanced maximal upper-body strength increases performance in sprint kayaking. J Strength Cond Res 37(4): e305-e312, 2023-The association between upper-body strength and performance in 200-m flat-water sprint kayak is not fully elucidated. Therefore, the aim of study 1 was to investigate the relationship between upper-body strength and kayaking performance. In study 2, the aim was to perform a randomized training intervention to investigate whether a causal relationship was present between an increase in strength and an actual change in 200-m kayaking performance. In study 1, 37 (22 men and 15 women) elite kayak paddlers performed tests of maximal power output, isometric force, 1 repetition maximum (1RM), and 40 seconds of maximal repetition number in bench press and bench pull and a 30-second all-out on-water sprint kayak test. In study 2, 26 (16 men and 10 women) national elite junior A, U23, and senior kayak paddlers were allocated into 2 groups: a training group (TRAIN) and a maintenance group (MAIN). Each group completed a 6-week strength training intervention with the purpose of either increasing 1RM in bench press (TRAIN) or maintaining strength (MAIN). Pre- and posttests were performed in 200-m kayak ergometer sprint, 1RM bench press, and 1RM bench pull. In study 1, 1RM in bench press was the best predictor of 30-second on-water kayaking performance with a regression coefficient of 0.474. In study 2, TRAIN significantly increased 1RM strength in bench press (pre: 87.3 ± 21.2 kg, post: 93.9 ± 21.3 kg, p = 0.001) and bench pull (pre: 84.2 ± 15.3 kg, post: 86.0 ± 15.1 kg, p = 0.025). In the 200-m kayak ergometer sprint test, TRAIN significantly decreased the time to complete the test (pre: 44.8 ± 4.3 seconds, post: 44.3 ± 4.3 seconds, p = 0.042). In bench press, 1RM was the best predictor of 200-m kayaking, and an increase in bench press 1RM resulted in increased kayaking performance.

Quantifying Paddling Kinematics through Muscle Activation and Whole Body Coordination during Maximal Sprints of Different Durations on a Kayak Ergometer: A Pilot Study

Paddling technique and stroke kinematics are important performance factors in flatwater sprint kayaking and entail significant energetic demands and a high strength from the muscles of the trunk and upper limbs. The various distances completed (from 200 m to 1000 m) require the athletes to optimize their pacing strategy, to maximize power output distribution throughout the race. This study aimed to characterize paddling technique and stroke kinematics during two maximal sprints of different duration. Nine nationally-trained participants (2 females, age: 18 ± 3 years; BMI: 22.2 ± 2.0 Kg m^-1) performed 40 s and 4 min sprints at maximal intensity on a kayak ergometer. The main findings demonstrated a significantly greater mean stroke power (237 ± 80 W vs. 170 ± 48 W; p < 0.013) and rate (131 ± 8 spm vs. 109 ± 7 spm; p < 0.001) during the 40 s sprint compared to the 4 min sprint. Athletes used an all-out strategy for the 40 s exercise and a parabolic-shape strategy during the 4 min exercise. Despite the different strategies implemented and the higher muscular activation during the 40 s sprint, no change in paddling technique and body coordination occurred during the sprints. The findings of the present study suggest that the athletes constructed a well-defined profile that was not affected by fatigue, despite a decrease in power output during the all-out strategy. In addition, they regulated their paddling kinematics during the longer exercises, with no change in paddling technique and body coordination.

The validity of using inertial measurement units to monitor the torso and pelvis sagittal plane motion of elite rowers

In elite sport, inertial measurement units (IMUs) are being used increasingly to measure movement in-field. IMU data commonly sought are body segment angles as this gives insights into how technique can be altered to improve performance and reduce injury risk. The purpose of this was to assess the validity of IMU use in rowing and identify if IMUs are capable of detecting differences in sagittal torso and pelvis angles that result from changes in stroke rates. Eight elite female rowers participated. Four IMUs were positioned along the torso and over the pelvis of each athlete. Reflective markers surrounded each IMU which were used to compute gold-standard data. Maxima, minima, angle range and waveforms for ten strokes at rates of 20, 24, 28 and 32 strokes per minute were analysed. Root mean square errors as a percentage of angle range fell between 1.44% and 8.43%. In most cases when significant differences (p < 0.05) in the angles were detected between stroke rates, this was observed in both IMU and gold-standard angle data. These findings suggest that IMUs are valid for measuring torso and pelvis angles when rowing and are capable of detecting differences that result from changes in stroke rate.

Effects of Four-Week Kayak Training on Three-Dimensional Paddling Kinetics, Body Kinematics, and Electromyography Activity in a Novice Paddler: A Case Study

From a biomechanical viewpoint, no longitudinal quantitative studies have been conducted on inexperienced paddlers. The present study aimed to investigate changes in three-dimensional paddling kinetics and kinematics, whole-body kinematics, and muscle activity with four-week on-water kayak training in a novice paddler. The participant practiced kayak paddling on river for four weeks. Before and after training, paddling kinetics and kinematics, body kinematics, and electromyography (EMG) activity were measured using a kayak ergometer. After the four-week training, the time required for on-water paddling for 270 m was reduced by 7.3% from pre to post training, while the average impulse in the x-direction significantly (P < 0.001, partial eta squared [η²] = 0.82) increased from 71.9 ± 1.9 to 91.1 ± 5.4 N kg⁻¹ s⁻¹. Furthermore, with training, the stroke rate and stroke length in the x-direction significantly (P < 0.001, partial η² = 0.80 and 0.79, respectively) increased from 62.8 ± 1.2 to 81.0 ± 2.9 spm and from 1.53 ± 0.04 to 1.71 ± 0.02 m, respectively. After training, the transition time significantly (P < 0.001, partial η² = 0.32) decreased (from 0.04 ± 0.01 to 0.01 ± 0.01 s), and there was an increase in paddle catch position (from −0.88 ± 0.01 to −1.04 ± 0.03 m). The pull time was not significantly changed (P = 0.077, partial η² = 0.08) because of the increasing stroke length after training, meaning that substantial pull time, which defined as pull time relative to the stroke displacement, was shorter in post-training than in pre-training. The relative change in average impulse in the x-direction with training was significantly (r = 0.857, P = 0.014) correlated with that of vastus lateralis EMG. These results indicated that after four-week kayak training of the novice paddler, the key mechanism underlying time reduction to perform on-water paddling for 270 m was associated with (1) increased average impulse along the propulsive direction caused by an increase in vastus lateralis EMG and (2) a higher stroke rate, which was attributed to a reduction in the pull and transition times.

Mean maximal power from an on-water 1000-m time-trial predicts lactate threshold power in well-trained flat-water sprint kayak athletes

This study utilised on-water graded exercise tests (GXT) to determine the power output (PO) corresponding to the first and second lactate thresholds (LT₁PO and LT₂PO), subsequently examining their relationship to the mean maximal power (MMP) and race time achieved across three on-water sprint kayak time-trials. Twelve well-trained sprint kayak athletes completed an on-water GXT and a 200-, 500- and 1000-m time-trial utilising novel instrumented paddle technology. Stepwise multiple regression was used to determine whether equations incorporating 200-, 500- and 1000-m MMP data could be used as an alternative method for estimating LT₁PO and LT₂PO. On-water GXT derived LT₁PO and LT₂PO were 151 ± 34 and 194 ± 39 W, respectively. For the 200-, 500- and 1000-m time-trials, MMP were 528 ± 143, 358 ± 92 and 287 ± 67 W, respectively. Athletes' LT₁PO and LT₂PO had very-large inverse relationships to 200-, 500- and 1000-m time-to-completion (r = -.71 to -.85, P ≤ .010) and very-large, to near-perfect positive relationships to 200-, 500- and 1000-m MMP (r = .81 to .94, P ≤ .001). The equation incorporating 1000-m MMP alone provided the best prediction of LT₁PO and LT₂PO, explaining 78% and 88% of the variance, and yielding a standard error of estimate (SEE) of 11.3% and 7.1% for these measures, respectively. The results of this study provide further evidence to support the ecological validity of recently developed on-water GXTs graded by PO, since LT₁PO and LT₂PO were significantly correlated to 200-, 500- and 1000-m performance. Practitioners could also predict LT₂PO with reasonable accuracy based solely from a 1000-m time-trial; potentially providing an alternative, non-invasive, competition-specific protocol for threshold determination.Highlights The fact that LT1PO and LT2PO had very-large, to near-perfect positive relationships to 200-, 500- and 1000-m MMP suggests that coaches should consider these relative submaximal aerobic-fitness variables when evaluating the performance of sprint kayak athletes, regardless of their race specialty.While the SEE and 95% limits of agreement (95%LoA) values for the prediction of LT₁PO may be too large to be practically meaningful, measures of LT₂PO could be predicted with a reasonable level of accuracy based upon 1000-m MMP.The ability to inform athletes' LT₂PO from a single 1000-m time-trial is advantageous since it would provide a more feasible, and time-efficient testing protocol within the athletes' training schedule compared to GXTs, potentially allowing coaches and practitioners to monitor changes in LT₂PO, and subsequently review individual training zones, more regularly.Given that LT₁PO and LT₂PO derived from on-water GXTs had very-large, to nearly perfect relationships to 200-, 500- and 1000-m performance, practitioners may prefer to use on-water, rather than laboratory-based GXTs given their greater practical significance and ecological validity.