Tomohiro GonjoHeriot-Watt University
Tomohiro Gonjo
PhD
About
55
Publications
14,827
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433
Citations
Introduction
Additional affiliations
April 2019 - present
June 2017 - March 2019
May 2015 - May 2017
Education
January 2012 - November 2016
April 2009 - March 2011
April 2005 - March 2009
Publications
Publications (55)
This study aimed to evaluate the test-retest reliability of a sprint performance test with semi-tethered front crawl swimming to indirectly assess the current potential to perform at maximal anaerobic effort in adolescent swimmers. Eight adolescent swimmers participated in this study (gender: females (n = 4) aged 13.0 ± 0.8 years, body height 1.6 ±...
Purpose:
The present study aimed to establish differences in load-velocity profiling, active drag (AD), and drag coefficient (Cd) between 3 age groups of female swimmers.
Methods:
Thirty-three swimmers (11, 13, or 16 y old) were recruited. The individual load-velocity profile was determined for the 4 competitive swimming strokes. The maximal vel...
Swimming is a time-based sport and hence strongly dependent from velocity. Most studies about swimming refer to velocity as discrete variable, i.e., 0-D (no time dimension). However, it was argued that using swimming velocity as a continuous variable (1-D, with time dimension) with Statistical Parametric Mapping (SPM) can bring deeper and detailed...
Swimmers perform better times in short course due to the greater numbers of turns; however, the differences between short (SC) and long course (LC) depending on the swimmers' age and sex are unclear. The main aim of this study was to analyse the differences in seasonal best times between SC and LC in freestyle events in relation to age and sex. Sea...
This case study examined the association between 50 m freestyle and speed curve parameters of a world-class Paralympic swimmer and analyzed the changes in speed curves and their frequency components across performance levels. From 2018 to 2021, a visually impaired female swimmer (26.59 s in 50 m freestyle, S12 class) underwent 22 tests to obtain in...
Objectives:
Swimming intra-cycle velocity fluctuation has often been assessed using the coefficient of variation, which requires a mathematical assumption of a positive linear relationship between the velocity mean and standard deviation. As this assumption has never been tested, the current study aimed to investigate the within-participant relati...
Free-swimming performance depends strongly on the ability to develop propulsive force and minimise resistive drag. Therefore, estimating resistive drag (passive or active) may be important to understand how free-swimming performance can be improved. The purpose of this narrative overview was to describe and discuss experimental methods of measuring...
The purpose of the present study was to investigate the intra-and inter-individual variability in arm-leg coordination during the underwater phase of the turn segment in 200 m breast-stroke. Thirteen male swimmers were recruited and performed a 200 m breaststroke in a pre-calibrated 25 m pool. Sub-phases during the underwater segment were obtained...
The purpose of this study was to measure the lean mass (LM) of collegiate swimmers using DXA method, and to investigate whether the selection of the front-leg and rear-leg in a kick start stance is related to muscle mass. In addition, since it is expected that the swimmer's effective side is affected by the choice of fore-leg and rear-leg, the rela...
The purpose of the present study was to investigate differences between world-class individual medley (IM) swimmers and stroke-specialists using race analyses. A total of eighty 200 m races (8 finalists × 2 sexes × 5 events) at the 2021 European long-course swimming championships were analysed. Eight digital video cameras recorded the races, and th...
The purpose of the presents study was to investigate the reliability of the active drag (Da) assessment using the velocity perturbation method (VPM) with different external resisted forces. Eight male and eight female swimmers performed 25 m sprints with five isotonic loads (1–2–3–4–5 kg for females; 1–3–5–7–9 kg for males), which were repeated twi...
The purpose of this study was to investigate the relationship between swimming load-velocity slope and the active drag (Da) in front crawl. 19 female and 22 male swimmers were recruited and performed three 25 m front crawl sprints with different external loads (1, 3, 5 kg for females and 1, 5, and 9 kg for males) assigned by a robotic resistance de...
The study investigated relationships between backstroke sprint swimming performance and variables extracted from load-velocity profiles. Thirteen male swimmers performed 50 m backstroke and semi-tethered swimming with three progressive external loads. From 50 m backstroke, race time (T50m) swimming velocity (v50m), stroke length and frequency were...
A load-velocity profile can help coaches and practitioners analyze and compare swimmers' velocity and strength capabilities. Load-velocity profiling may also be used for establishing requirements for free swimming performance, and the slope (steepness of the regression line) could explain performance determinants in relation to propulsion and drag....
In Fiber Reinforced Plastics (FRP) molding, molds made of metal or epoxy resin blocks are commonly used, but the production time and material costs are high and not suitable for prototyping and small volume production. 3D printed molds have the potential to overcome these limitations, which would also enable frequent mold shape adjustment. The pres...
This study aimed to clarify the kinematic and kinetic parameters that identify the technical differences in the eggbeater kick. Twelve water polo players performed the eggbeater kick, and its kinematics were recorded by a motion capture system. Pressure distributions around the feet were measured by sixteen pressure sensors attached to the dorsal a...
The aim of this study was to review the literature on front crawl swimming biomechanics, focusing on propulsive and resistive forces at different swimming velocities. Recent studies show that the resistive force increases in proportion to the cube of the velocity, which implies that a proficient technique to miminise the resistive (and maximise the...
We examined the association between 50 m freestyle performance (50FS) and average speed (AS), peak speed (PS), minimum speed (MS) and intracyclic speed variation (ISV) and compared the speed curves from swimmers with different performance levels using functional analysis of variance (FANOVA). Fourteen male swimmers (50FS: 22.50 ± 0.58 s) performed...
The purpose of the present study was to investigate differences in a 100 m breaststroke time-trial between elite and sub-elite swimmers. Elite and sub-elite male swimmers (seven each; 772.1 ± 35.2 and 610.6 ± 24.7 FINA point, respectively) performed 100 m breast-stroke, which was recorded by a multi-camera system that provided the mean and time-ser...
Objectives
To investigate the arm–leg coordination from different perspectives of motor control during the underwater start sequence to understand whether differences exist between the three competitive breaststroke swimming events.
Design
Cross-sectional study.
Methods
Forty-one breaststroke races (with race times relative to the world record):...
In breaststroke races, the dolphin kick could finish before, at the same time, or during the arm pull-out, but it is unclear how swimmers perform this technique. The aim of this study was to investigate whether swimmers glide between the dolphin kick and arm pull-out, favour continuity or even overlap those two phases, as it would impact the active...
The purpose of the present study was to investigate differences between front crawl and backstroke swimming in hydrodynamic (produced by swimmers) and buoyant torque around the transverse axis. Ten swimmers performed 50 m front crawl and backstroke at four selected velocities (same velocities for both techniques). All trials were recorded by four u...
In biomechanics, human motion is described as rigid body dynamics due to the complex nature of the human body. During movements, the human body presents many types of deformation, such as stretching, bending, bulging and jiggling, which make precise assessments of physical interactions occurring in the human body extremely difficult. Therefore, for...
The purpose of the present study was to establish relationships between sprint front crawl performance and a swimming load-velocity profile. Fourteen male national-level swimmers performed 50 m front crawl and semi-tethered swimming with three progressive loads. The 50 m performance was recorded with a multi-camera system, with which two-dimensiona...
The current study investigated body roll amplitude and timing of its peak in backstroke and compared them with front crawl swimming. Nineteen anatomical landmarks were digitised using 80 swimming trial videos (ten swimmers × two techniques × four intensities) recorded by two above-and four below-water cameras. One upper-limb cycle was analysed for...
Researchers have quantified swimming races for several decades to provide objective information on race strategy and characteristics. The purpose of the present review was to summarize knowledge established in the literature and current issues in swimming race analysis. A systematic search of the literature for the current narrative review was cond...
The purposes of this study were to establish relationships between selected underwater kinematics and the starting and turning performances and to quantify kinematic differences between these segments in sprint butterfly swimming. Fourteen male swimmers performed 50 m maximal butterfly swimming in a short course pre-calibrated pool. The entire race...
This study aimed to assess kinematic and kinetic changes in front crawl with various stroke frequency (SF) conditions to investigate why swimming velocity (SV) does not increase above a certain SF (SF max). Eight male swimmers performed 20 m front crawl four times. The first trial involved maximal effort, whereas SF was controlled during the next t...
The purpose of this study was to investigate differences in Froude efficiency (ηF) and active drag (DA) between front crawl and backstroke at the same speed. ηF was investigated by the three-dimensional (3D) motion analysis using 10 male swimmers. The swimmers performed 50 m swims at four swimming speeds in each technique, and their whole body moti...
Background and aim:
To identify kinematic variables related to short course 100 m breaststroke performance.
Methods:
An automatic race analysis system was utilized to obtain start (0-15 m), turn (5 m before the wall until 10 m out), finish (95-100 m), and clean swimming (the rest of the race) segment times as well as cycle rate and cycle length...
The purposes of this study were to establish test-retest reliability of load-velocity profile outcome measurements in front crawl swimming calculated from three and five different external loads, and if outcome results were comparable between calculation methods. Seven females and eight males performed 25 m semi-tethered swimming with five progress...
The aim of this study was to compare artistic swimmers (ASs) and water polo players (WPs) in their polyrhythmic production ability and entrainment between arm and leg motion frequency. Nine ASs and nine WPs participated in the study. First, we assessed the natural eggbeater kick frequency of each participant without any additional motion for 20 s....
The purpose of this study was to compare body wave characteristics between butterfly swimmers with different competitive levels as a case study. An international and a regional level swimmer performed a 50 m butterfly with their maximum effort, and their one stroke cycle velocity, stroke frequency, stroke length, and the vertical coordinate of the...
The aim of this study was to determine the influence of torso morphology on maximum instantaneous hydrodynamic resistance in front crawl swimming. Outlines of the torso in the frontal and anteroposterior planes were calculated from photographic images to determine continuous form gradients (m/m) for the anterior, posterior and lateral aspects of th...
This study compares polyrhythmic production ability between water polo players (WPs), artistic swimmers (ASs) and drummers (Ds), to assess how their differing experiences in coordinating complex inter-limb activity with music affected this ability. Eight ASs, eight WPs and eight Ds participated. They were asked to perform finger and foot taps in a...
The purpose of this study was to establish the relationships between 50 m sprint swimming performance and variables acquired from a swimming load-velocity profile established by semi-tethered butterfly swimming. Twelve male elite swimmers participated in the present study and performed 50 m sprint and semi-tethered butterfly swimming with different...
The purpose of this study was to investigate why front crawl is faster than backstroke from a kinematic perspective. Three-dimensional kinematics were obtained from one upper-limb cycle of ten male competitive swimmers performing 50 m front crawl and backstroke trials at maximum speed. Swimmers achieved faster centre of mass velocity in front crawl...
The purpose of this study was to establish the asymmetry and body wave characteristics related to shoulder, hip, knee, and ankle roll in unilateral arm amputee swimmers. Three unilateral arm amputee swimmers, including one Paralympic medallist (swimmer A), volunteered in this study. They conducted two 10-15 s front crawl tests with sub-maximum and...
Human undulatory underwater swimming (UUS) is an underwater propelling technique in competitive swimming and its propulsive mechanism is poorly understood. The purpose of this study was to visualize the three-dimensional (3D) flow field in the wake region during human UUS in a water flume. A national level male swimmer performed 41 UUS trials in a...
The purpose of this study was to investigate whether swimmers follow the instructed speed (vtarget) accurately with the aid of a commercial visual light pacer during front crawl and backstroke swimming in a 25 m pool. Ten male swimmers performed 50 m front crawl and backstroke at different speeds (controlled by a visual light pacer) in a 25 m pool....
This paper proposes an online estimation method of swimmer's inter-limb coordination (ILC) by means of a wearable sensor suit. A recurrent neural network-based ILC estimation algorithm was implemented and then a validation experiment was conducted with three participants. As the result, the wearer's ILC was accurately measured and the possibility o...
The purpose of this study was to investigate the relationship between active drag and swimming velocity during front-crawl swimming using the MRT-method (a methodology using the measured values of residual thrust) and the MAD-system with the same group of swimmers. Six male swimmers swam front-crawl with (Whole stroke: WS) and without leg motion (a...
Purpose
The purpose of this study was to determine kinematic and energetic differences between front crawl and backstroke performed at the same aerobic speeds.
Methods
Ten male competitive swimmers performed front crawl and backstroke at a pre-determined sub-anaerobic threshold speed to assess energy cost (through oxygen uptake measurement) and ki...
The purpose of this study was to identify the characteristics of maximum shoulder and hip roll angles in back crawl at different swimming speeds. Ten male elite swimmers performed back crawl at four different swimming speeds. The swimming trials were filmed by a total of six digital video cameras and three-dimensional coordinates of swimmer's anato...
The purpose of this study was to explore the reliability of esti-mating three-dimensional (3D) angular kinematics and kinetics of a swimmer derived from digitized video. Two high-level front crawl swimmers and one high level backstroke swimmer were recorded by four underwater and two above water video cameras. One of the front crawl swimmers was di...
The purpose of this study was to explore the reliability of estimating three-dimensional (3D) linear kinematics and kinetics of a swimmer derived from digitized video and to assess the effect of framing rate and smoothing window size. A stroke cycle of two high-level front crawl swimmers and one high level backstroke swimmer was recorded by four un...
Due to the difficulty of measuring forces and torques acting on a swimmer during mid-pool swimming, an inverse dynamics approach is required. Personalised body segment parameter (BSP) data enabling calculation of net forces and torques can be obtained using the elliptical zone method. The purpose of this study was to establish the reliability of es...
This study experimentally investigated the possible relationship between energy expenditure and skin
temperature during 2x 300m protocols (front crawl and backstroke), performed at the same intensity and velocity, in two national level male swimmers. Both swimming techniques increased skin temperature but with different thermal patterns. Higher va...
Questions
Question (1)
I am planning to conduct multiple ANOVAs or MANOVA and struggling to understand the benefit of MANOVA in terms of low Type I error risk (which is written in all textbooks, websites and articles I have gone through). Obviously, when it comes to the overall effect, it is understandable. However, many studies do follow-up analyses using Univariate tests (which is basically ANOVAs) anyway to see how large the effect on each dependent variable is. In this case, this does not reduce the risk of Type I error, does it? Or do people make some familywise error rate corrections in the Univariate tests?
