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This review updates the swim-start state of the art from a biomechanical standpoint. We review the contribution of the swim-start to overall swimming performance, the effects of various swim-start strategies, and skill effects across the range of swim-start strategies identified in the literature. The main objective is to determine the techniques to focus on in swimming training in the contemporary context of the sport. The phases leading to key temporal events of the swim-start, like water entry, require adaptations to the swimmer's chosen technique over the course of a performance; we thus define the swim-start as the moment when preparation for take-off begins to the moment when the swimming pattern begins. A secondary objective is to determine the role of adaptive variability as it emerges during the swim-start. Variability is contextualized as having a functional role and operating across multiple levels of analysis: inter-subject (expert versus non-expert), inter-trial or intra-subject (through repetitions of the same movement), and inter-preference (preferred versus non-preferred technique). Regarding skill effects, we assume that swim-start expertise is distinct from swim stroke expertise. Highly skilled swim-starts are distinguished in terms of several factors: reaction time from the start signal to the impulse on the block, including the control and regulation of foot force and foot orientation during take-off; appropriate amount of glide time before leg kicking commences; effective transition from leg kicking to break-out of full swimming with arm stroking; overall maximal leg and arm propulsion and minimal water resistance; and minimized energy expenditure through streamlined body position. Swimmers who are less expert at the swim-start spend more time in this phase and would benefit from training designed to reduce: (i) the time between reaction to the start signal and impulse on the block, and (ii) the time in transition (i.e., between gliding and leg kicking, and between leg-kicking and full swimming). Key pointsSWIMMERS MEET TWO MAIN CONSTRAINTS DURING THE START MOVEMENT: travelling more distance in the air (to get less resistance) and rotate to enter properly in the water.Swim start is a sum of compromises in all parts of it, and swim-start expertise is distinct from swim stroke expertise corresponding to best ways to manage these compromises.Variability found is contextualized as having a functional role and operating across multiple levels of analysis.
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A REVIEW OF FREESTYLE DIVE STARTS: A BIOMECHANICAL PERSPECTIVE.
Vantorre J. 1, Chollet D. 1 and Seifert L. 1
1 C.E.T.A.P.S. Laboratory UPRES EA 3832: University of Rouen, Faculty of Sports Sciences, France
ABSTRACT
This paper updates swim-start state of the art from a biomechanical standpoint. The contribution of
the swim-start to overall swimming performance was reviewed, including the effects of various
swim-start strategies, and skill effects across the range of swim-start strategies identified in the
literature. The main objective was to determine the techniques on which to focus in swimming
training in the contemporary context of the sport. The phases leading to key temporal events of the
swim-start, like water entry, require adaptations to the swimmer’s chosen technique over the course
of a performance; we thus define the swim-start as the moment when preparation for take-off
begins, to the moment when the swimming pattern begins. A secondary objective is to determine
the role of adaptive variability as it emerges during the swim-start. Variability is contextualized as
having a functional role and operating across multiple levels of analysis: inter-subject (expert versus
non-expert), inter-trial or intra-subject (through repetitions of the same movement), and inter-
preference (preferred versus non-preferred technique). Regarding skill effects, we assume that swim-
start expertise is distinct from swim stroke expertise. Highly skilled swim-starts are distinguished in
terms of several factors: reaction time from the start signal to the impulse on the block, including the
control and regulation of foot force and foot orientation during take-off; appropriate amount of glide
time before leg kicking commences; effective transition from leg kicking to break-out of full
swimming with arm stroking; overall maximal leg and arm propulsion and minimal water resistance;
and minimized energy expenditure through streamlined body position. Swimmers who are less
expert at the swim-start should spend more time in this phase and would benefit from training
designed to reduce: (i) the time between reaction to the start signal and impulse on the block, and
(ii) the time in transition (i.e., between gliding and leg kicking, and between leg-kicking and full
swimming).
KEYWORDS:
Biomechanics, expertise, performance, techniques, variability
LITERATURE SEARCH METHODOLOGY
MEDLINE and ScienceDirect were searched for primary sources using six keywords: expertise,
performance, technique, variability, swimming and start. These were pooled (via Boolean operation
“OR”) and combined (via Boolean operation “AND”) with similarly pooled keywords related to
swimming biomechanics. The proceedings of international congresses on biomechanics and
swimming databases also were searched, from their earliest available records up to November 2012.
Relevant articles were sought on Google Scholar, and the cited articles and reference lists of all
included studies were carefully scrutinized. The articles analyzing swim-starts were restricted to
those written in English. Full publications and abstracts were screened, and all relevant studies were
retrieved. A standardized form was used to select the studies eligible for inclusion. Ultimately, 45
references and eight books were selected from the previously selected articles and books from the
MEDLINE, ScienceDirect and Google Scholar searches; an additional 17 references were retrieved
from the proceedings of sport sciences congresses. Disagreement was resolved by achieving
consensus among the authors, who took into account the size of the population studied and the
swimming skill level for inclusion.
THE START IN A SWIMMING EVENT
Recently, interest in swimming-specific research has begun to accelerate (Pelayo & Alberty, 2011).
Indeed, Vilas-Boas (2010) noted that swimming is now one of the most investigated physical
activities, based on the number of published research articles and the number of countries
represented at international meetings. Part of this rise in interest may be related to the ongoing
modifications in the swimming rules, driven by changes in swimming techniques and technologies, all
of which have inspired new research directions. This includes the swim-start (SW 7 of the FINA rules),
which has undergone several changes from a regulatory point of view. For example, on January 1,
2010, a new kick-start block was introduced, with a raised rear section to assist the track start
technique (Omega OSB11). Competition analysis has provided information on the start time (to 15-
m), turn times (7.5-m into and out of the wall), and finish time (5-m into the wall), as well as the
stroke length, stroke rate and velocity, for each 25-m section of free swimming (Mason & Cossor,
2000). Moreover, the start time has been quantitatively evaluated in relation to the swimming, turn
and finish times in order to assess its contribution to overall performance (Arellano et al., 1996;
Costill et al., 1992; Lyttle & Benjanuvatra, 2005; Mills & Gehlsen, 1996; Vilas Boas et al., 2003). The
results indicate that the start time to 15-m can account for anywhere between 0.8% in long distance
events and 26.1% of the total race time in sprint events (Lyttle & Benjanuvatra, 2005). Moreover,
contrary to the block starts in track and field, in which the athlete has to accelerate from zero to full
running speed, dive swim-starts enable swimmers to enter the water faster than average swimming
speed, which further underlines the great importance of the swim-start in sprints. Effective diving
techniques enable swimmers to exploit the speed generated during the dive and are in line with the
principle of efficiency that drives every phase of the competitive event (Kilduff et al., 2011; Lyttle &
Blanksby, 2011).
ANALYSIS OF SWIMMING START KINEMATICS
Methodology
The studies on the swim-start have analyzed several parameters. Kinematic analyses of swim-start
behavior and performance, for example, have usually compartmentalized the start into distinct
phases, such as block time, flight time and underwater time (Arellano et al., 1996; Cossor and Mason,
2001; Vilas-Boas et al., 2003). More recent studies have assumed that the start actually begins with
the reaction to the start signal and the push from the block (Benjanuvatra et al., 2007; Bishop et al.,
2009; De la Fuentes et al., 2003; Slawson et al., 2012). These trials were recorded at 50 Hz with a
digital video camera placed perpendicularly to the direction of movement. Vantorre et al. (2010a)
used both fixed cameras (placed at 5-m and 15-m) to determine phase limits, and underwater mobile
cameras on a trolley to analyze qualitative variables and stroking parameters like stroke length or
frequency. The forces applied during the push from the starting block were analyzed via custom-
built, instrumented starting blocks. Force curves measured the impulse in the horizontal and vertical
axes (in N.kg-1) (Benjanuvatra et al., 2007; Blanksby et al., 2002; Lee et al., 2001; Slawson et al., 2012;
Vantorre et al., 2010b, 2010c; Vilas-Boas et al., 2003; West et al., 2011). The kinetic analysis of the
block phase quantified the impulse and described its direction relative to the direction of movement
(Benjanuvatra et al., 2007; Blanksby et al., 2002; Lee et al., 2001; Slawson et al., 2012; Vantorre et al.,
2010b, 2010c; Vilas-Boas et al., 2003).
Block Phase
Several studies of swim-start phase kinetics, particularly the reaction time on the starting block and
the flight and entry phases, have drawn parallels with the start in track and field (Ayalon et al., 1975;
De la Fuentes et al., 2003; Issurin & Verbitsky, 2003; Krüger et al. 2003; Miller et al., 2003; Vilas-Boas
et al., 2003; Zatsiorsky et al., 1979). However, from a biomechanical point of view, these starts differ
in many ways. Moreover, among swimmers, the starts also differ according to specialty. Sprint
swimmers need to rotate backwards to bring themselves upright, whereas longer-distance swimmers
need to focus on the distance covered while in the air and the body orientation at water entry. Here,
breaking down the swim-start is not only a spatial matter, but also a matter of motor changes during
the overall start movement. From this perspective, studies on the block phase (Benjanuvatra et al.,
2007; Vantorre et al., 2010a) have shown that two distinct actions must be optimized: a rapid
reaction to the start signal and high impulse generated over the starting block. The studies on the
block phase have usually been kinetic analyses focused on the force applied to the block or on
training programs designed to improve the start (Bishop et al., 2009; Breed & Young, 2003; De la
Fuentes et al., 2003; Lee et al., 2001). The reaction time needs to be as brief as possible, while the
movement phases on the block need to last long enough to maximize the swimmer’s impulse to
achieve high horizontal velocity (Breed & Young, 2003). In other words, a compromise needs to be
struck between spending too much time on the block to create more force and spending too little
time on the block to minimize the time deficit and avoid being “left at the start” (Lyttle et al., 1999).
Flight and Entry Phases
Breaking down a swim-start into its component parts can be challenging as the phases are not always
clear cut. Maglischo (2003) defined water entry as the moment when the hand enters the water. This
definition is widely used to determine the end of the flight phase, during which swimmers need to
jump as far as possible and travel the maximum distance at the high velocity developed during the
block phase (Hubert, Silveira, Freitas, Pereira, & Roesler, 2006; Sanders & Byatt-Smith, 2001). Ruschel
et al. (2007) reported that flight duration is not correlated with start time but that flight distance is
one of the variables that determine starting performance (r=-0.482). Maglischo (2003) noted that the
block phase strongly influences the flight phase by imposing a compromise between the pike and flat
styles for the aerial trajectory (Maglischo, 2003). The pike start has a longer start time, greater take-
off and entry angles, and a shorter distance to head entry into the water than the flat start
(Counsilman, Counsilman, Nomura, & Endo, 1988). Wilson and Marino (1983) showed a shorter 10-m
start time, greater entry angle, shorter distance to water entry, and greater hip angle at entry for the
pike start than for the flat start. However, after five training sessions, Kirner et al. (1989) reported
that the grab start/flat entry showed a shorter 8-m start time and a smaller entry angle than the grab
start/pike entry. Thus, the flat start aims for a quick entry into the water using a flatter body position
and earlier stroking. The pike start creates a smaller hole for water entry (i.e., angle of entry more
vertical to the water surface) with higher velocity due to the influence of gravity, but it requires a
horizontal (body position from the surface) then vertical(until break out the water surface)
underwater recovery, which causes higher resistance. Vantorre et al. (2010a) studied swim-starts and
found that strategies differ, even among elite swimmers. These authors observed that the swim-start
profiles included differences in how the limbs were used to achieve specific trajectory styles, such as
the Volkov start, with the arms back during the leg impulse; or the flight style start, with the arms
directly in front of the head (Vantorre et al., 2010a). However, the swimmer’s task during the flight
phase is not merely to go as far as possible. Mclean et al. (2000) and Vantorre et al. (2010a; 2010b)
showed that swimmers must also generate enough angular momentum to make a clean entry into
the water, which means that they need sufficient time to rotate while in flight in order to enter the
water through a small hole. Arm movements influence angular momentum and during the forward
rotations of the swim-start, a forward arm swing decreases rotation and, inversely, backward
rotations increase body rotation (Bartlett, 2007). Therefore, to manage the angular momentum
generated during the block phase, swimmers can make a flat start (less angular momentum and a flat
trajectory) or a Volkov start with a backward arm swing (more angular momentum and a pike
trajectory) (Seifert et al., 2010; Vantorre et al., 2010d). Swimmers enter the water at an angle
maintained during the descent phase of flight.
Glide Phase
After the aerial phases (block, flight and entry phases), swimmers have to manage the transition
from air to water (Maglischo, 2003), with the glide beginning when the head enters the water and
ending when the head breaks out (Counsilman et al., 1988). After water entry, the swimmer remains
in a streamlined position for as long as possible to maintain the velocity acquired in previous phases
and progressively assumes a horizontal position: this is the glide phase. Cossor and Mason (2001) and
Sanders (2004) indicated that finish performances are highly correlated with the swim-start time
spent underwater during the glide phase. However, few studies have actually measured this, with
most focusing on the aerial phase. De Jesus et al. (2011) showed the importance of the compromise
between underwater velocity and backstroke start performance. Guimaraes and Hay (1985) and Hay
(1988) concluded that glide time is more important to the start phase than either block time or flight
time (explaining 95% of the variance of the starting time for r = 0.97). Maintaining a streamlined
body position after water entry is vital to slowing the loss of velocity. Clear evidence of this is shown
when swimmers are being towed, as they produce greater hydrodynamic resistance in the supine
position than in the prone position (Clarys & Jiskoot, 1975; Counsilman, 1955). These observations
indicate that body shape, rather than surface area, is the decisive component when determining the
proportion of the total resistance. For example, placing one hand on top of the other, as opposed to
positioning the hands in shoulder alignment, caused a 7% decrease in resistance (Bulgakova &
Makarenko, 1966) (Figure 1).
Figure 1. Impact of body shape on flow resistance when the body is pulled (proportion of resistance in relation
to total resistance in gliding position corresponding to 100%) (Bulgakova and Makarenko, 1996)
Given the importance of this phase for starting performance, some authors have developed methods
to quantify the quality of gliding with drag coefficients using computational fluid dynamics analysis
(Naemi et al., 2010; Naemi & Sanders, 2008; Vilas-Boas et al., 2010). Bixler et al. (2007) validated this
tool for swimming studies. The glide factor is the measure of glide efficiency that accounts for the
combined effects of resistive forces and added mass. The quality of gliding is thus measured in terms
of the adopted posture and the flow characteristics around the swimmer’s body. The glide factor
(expressed in meters) is attained when a gliding body (the swimmer) has an initial velocity of 2 m.s-1
and decelerates to 1 m.s-1 in half a second. Naemi & Sanders (2008) showed that this is linked to the
swimmer’s size and shape. The inertial and resistive characteristics of a streamlined body affect the
glide efficiency.
Underwater Propulsion
Swimmers must manage the glide, underwater kicking and the break-out to start swim stroking
(Elipot et al., 2009; 2010; Maglischo, 2003; Vantorre et al., 2010a). Thus, the swim-start is not just
limited to the block and aerial phases, but continues until the swimmer re-surfaces and commences
swim stroking up to the 15-m mark in all strokes except the breaststroke, according to FINA rules.
Few studies have analyzed the underwater phase of the start even though it contributes considerable
distance at the beginning of a race, particularly in the breaststroke (Arellano et al., 1996; Cossor &
Mason, 2001; Guimaraes & Hay, 1985; Vilas-Boas et al., 2003). Cossor and Mason (2001) found a
negative correlation (r =-0.734) between the underwater velocity and the 15-m start time in 100-m
backstroke and 100-m breaststroke events, thereby suggesting the value of high velocity during the
underwater phase to achieve high swim velocity. Some authors have underlined the importance of
quantifying the underwater phase of the start (Sanders, 2002), but few have focused on doing so, or
on underwater leg propulsion (Blanksby et al., 1996; Clothier et al., 2000; Elipot et al., 2010; Lyttle et
al., 1998, 2000; Takeda et al., 2009). Indeed, despite a paucity of data, authors acknowledge that the
underwater phase time is fundamental to achieving an effective swim-start (Sanders, 2004; Vilas-
Boas et al., 2003; Vilas-Boas et al., 2000). This conviction was expressed in the study of Pereira et al.
(2003), who suggested that the time between water entry and the 15-m mark is the most important
variable in swim-start performance. For all strokes other than breaststroke, only the legs are used
during the underwater phase. The underwater phase in breaststroke is specifically defined by the
FINA rules as follows: after the start and after each turn, the swimmer may take one arm stroke
completely back to the legs during which the swimmer may be submerged. A single butterfly kick is
permitted during the first arm stroke, followed by a breaststroke kick (SW 7.1 FINA). This
specification has led some authors to analyze the propulsive and gliding actions, and the velocity
during this part of the start (Seifert, Vantorre, & Chollet, 2007; Vilas-Boas et al., 2010). These authors
showed that both national and international swimmers often demonstrate a similar problem: a
negative superimposition of leg propulsion with arm recovery at the pull-out phase, which is resolved
at the first swim stroke. Furthermore, these authors showed that the difficulty in achieving optimal
arm-leg coordination is due to an increase in velocity that limits the scope for adaptive variability. In
freestyle, swimmers generally begin stroking too early, which generates more drag than if they had
continued gliding for an extended period (Sanders & Byatt-Smith, 2001). Elipot et al. (2010) also
emphasized the importance of the relationship between gliding and underwater kicking to maintain
the velocity acquired by the diving start. Houel et al. (2012) stated that swimmers, ideally, should
start dolphin kicks after approximately 6-m of gliding and use an efficient, high rate of kicking. Motor
organization during the underwater phase should be optimized in relationship to these parameters.
A study of expert and non-expert swimmers described the underwater phase as including a leg
kicking phase and actually counted the number of leg undulations (Vantorre et al., 2010c). This
allowed the authors to distinguish gliding from leg propulsion in terms of relative duration and
quantity and pointed to the challenging transitions with regard to the respective parameters. The leg
kicking phase was calculated as the time between the beginning of leg propulsion and arm
propulsion: when kicking and stroking started at the same time, it was equal to 0 seconds; when the
swimmer started kicking before stroking, it was >0 seconds; and when the swimmer started
stroking before kicking, it was <0 seconds.
Kinematic Profiling
Vantorre et al. (2010a) segmented the start into six phases (see Figure 2): (i) block phase (the time
between the signal and the instant the swimmer’s toes leave the block), (ii) flight phase (the time
between the instant the toes leave the block and hand entry), (iii) entry phase (the time between
hand entry and toe immersion), (iv) glide phase (the time between toe immersion and the beginning
of the underwater propulsion of the legs), (v) leg kicking phase (the time between the beginning of
leg propulsion and arm propulsion), and (vi) swimming phase (the time between the beginning of the
first stroke and the arrival of the head at the 15-m mark).
Figure 2. Start phases to 15-m (Vantorre et al., 2010a).
The main objective of swim-start research has been to identify the most effective start technique in
terms of performance. Tools like stepwise regressions can be used to analyze various parts of the
start with a focus on qualitative aspects. For example, Vantorre et al. (2010a) investigated what
expert swimmers do during the underwater phase up to the 15-m mark, analyzing behavioral
parameters such as leg kicking, number of leg undulations, number of arm strokes, and arm
coordination to 15-m. These authors assessed the time spent in each phase and attempted to
determine the most effective profiles for start performances. Using these qualitative parameters,
cluster analysis determined whether the expert swimmers employed the same strategies to achieve
an optimal start. The profiles that emerged were in line with the two main attributes of an eective
start: recognizing the optimal time to stop gliding and begin leg kicking, and optimal transition from
leg undulation to full swimming.
EXPERTISE IN THE SWIMMING START
Definition
Swimming federations often define swimming levels using qualification grids. For maximal facility and
standardization, performances during swimming studies are expressed as trial times and expertise
can be characterized as a percentage of the world record (WR). Performances greater than or equal
to 90% of WR are considered to be elite. Thus, the swimming level is usually based on chronometric
performance. However, chronometric performance is an overly gross measure and may be
insufficient to define expertise, especially for practical purposes. For example, high performance has
been linked to the ability to start well, yet a swimmer can be an expert for the 50-m or 100-m event
(sprint events) but not be within the performance range commensurate a start expert. As previously
noted, the swim-start is one of several parts of an event and deserves to be considered as a distinct
skill. Seifert et al. (2007) and Vantorre et al. (2010c) found that the swim-start influences
coordination during the first strokes after break-out into swimming in both breaststroke and
freestyle. This is due to the high velocity acquired at the start and the glide plus movements
generated during the underwater propulsion period (Seifert et al., 2007; Vantorre et al., 2010c). Each
phase of the swim-start must be carefully coordinated to maximize the contribution to overall
performance.
Trembley and Fielder (2001) observed that swimmers try to obtain the highest explosive power from
the block, which requires a compromise between the optimal movement time and the time taken to
push off from the block. To optimize the block phase, Mason et al. (2006) found that expert
swimmers, regardless of the start technique, generated higher average acceleration on leaving the
block and that take-off angles were important discriminating parameters of performance. Wilson and
Marino (1983) specifically studied the influential factors in the aerial phase and reported low take-off
angles by elite swimmers (21.25 ± 5.59°) and a flight time phase of 0.30 ± 0.04s. Trembley and Fielder
(2001) reported that the best swim-starts were achieved by leaving the block quickly, traveling a
great distance in the air, and making a clean entry into the water with powerful underwater leg
propulsion. The importance of a clean entry and a streamlined glide position to maintain the velocity
acquired during the aerial phase was emphasized, as was the need for swimmers to delay the
moment when they begin stroking (i.e., a velocity greater than the instantaneous average swimming
velocity) (Sanders & Byatt-Smith, 2001). Zatsiorsky et al. (1979) found correlations between the glide
phase and the 5.5-m time (r=0.60 and r=0.94 at p<.05). Pereira et al. (2006) investigated the
underwater phase and showed significant correlations between the maximum depth reached during
the glide and the average velocity of the phase with the 15-m time (r=0.515 and r=-0.645). Less
skilled swimmers showed strong significant correlations (r= 0.98 at p<.05) between the underwater
phase and the start time (Arellano et al., 1996). Bloom et al. (1978) showed that leaving the block
quickly was important, but that sufficient time on the block was also important to generate force and
maximize initial velocity. Another study of underwater phases (Sanders, 2004) showed that expert
swimmers maximize propulsion and minimize resistance notably by adopting a streamlined position
and selecting appropriate glide times and underwater propulsion times before commencing free
stroking.
Skill Level Comparison
Few studies have directly compared expert and non-expert swimmers to characterize performance
using all the start variables. Benjanuvatra et al. (2007) showed significantly higher block values for
horizontal impulse (3.60 ± 0.23 versus 3.17 ± 0.30 N/kg) and lower take-off angles (27.45 ± 5.99°
versus 39.62 ± 13.19°) for elite swimmers. This indicated greater efficiency in the impulse of the
expert swimmers (better orientation of forces compared with the overall direction of the movement
than non-expert). Furthermore, the expert swimmers tried to go as fast and far as possible when
starting, whereas the non-experts had other aims: they tried to organize their limbs with regard to
gravity by managing the translation-rotation compromise during the push on the block, or they tried
to be hydrodynamic during the air-water transition of water entry.
Expertise can also be assessed in terms of adaptability (Warren, 2006), as when a swimmer performs
a start with a non-preferred technique. Sport biomechanists consider movement variability is an
important element with a functional role, and can be analyzed at three levels (Bartlett, Wheat, &
Robins, 2007; Bartlett, 2004).
The first level of analysis is between trials using the same technique (i.e., inter-trial and intra-
individual variability). By assessing multiple repetitions of the same skill, researchers determine the
phases during which variability occurs and then seek to understand how the task performance may
have been altered (Bartlett et al., 2004). For example, in a study based on only three trials for expert
and non-expert swimmers, no significant differences were found in the intra-class correlations (ICC)
for each swimmer of the two groups, nor did the expert swimmers show better reproducibility than
the non-experts (Vantorre et al., 2010c).
The second level of analysis is between the performances of swimmers with the same or different
levels of expertise (i.e., inter-subject variability). Vantorre et al. (2010c) also compared elite and non-
elite swimmers performing swim-starts using ICCs. The experts showed shorter impulse times but
higher impulse values in the horizontal and vertical axes than the non-expert swimmers. The data
indicated that the expert and non-expert swimmers used different strategies for the start and that
each group approached the task in a qualitatively different manner. For the non-expert swimmers,
the main feature was trying not to lose too much time on the start, especially between the reaction
to the starting signal and the impulse on the block. In contrast, the expert swimmers sought to
optimize a short block phase and a powerful, well-directed impulse. A second challenge for the non-
expert swimmers was to manage the transitions between gliding, leg kicking and full swimming,
while the expert swimmers tried to maintain a greater velocity by adopting a more streamlined body
position in order to start free swimming as far as possible from the block.
Vantorre et al. (2010a) and Seifert et al. (2010) used cluster analysis as an additional technique to
evaluate the role of variability between sujects. Seifert et al. (2010) showed that expert swimmers
organized themselves differently and used arm and leg movements during the aerial phase to enter
the water cleanly and as far as possible from the block. Vantorre et al. (2010a) showed that expert
swimmers developed different strategies from the start signal to the 15-m mark to achieve their
optimal performances.
The last level of analysis is inter-preference variability (i.e., between a preferential technique and a
non-preferential one), which could be useful in determining the adaptability of performers as they
manage changes in conditions. Vantorre et al. (2011) studied elite swimmers who habitually used a
grab start,when using both the grab start and the track start, the non-preferred skill. In line with
previous work (Hardt et al., 2009; Benjanuvatra et al. 2004), this study showed less loss of angular
momentum in dimensions other than the direction of movement when the swimmers used the
preferred grab technique; and lower efficiency using the non-preferred track start technique, in part
due to a twisting effect of this technique.
Vantorre et al. (2010a) used cluster analysis and showed that expert swimmers are distinguished by
start profiles, suggesting that a range of strategies can be used to achieve high start performance.
This range of profiles confirmed that each constraint may have more than one solution and, thus,
that expertise is not necessarily characterized by decreased movement variability. Instead, variability
may well reflect personal responses based on anatomy, with each individual finding a different motor
solution to achieve a “good start.” Indeed, in competition, one observes different start techniques
and variations of the same technique existing side by side.
The analysis of variability suggests that practitioners can evaluate which start technique is best suited
to a given swimmer from among a range of possible techniques. This is a process that requires
tracking individual performance changes over time. The final section reviews how swim-starts have
evolved so as to provide practitioners with an overview of the strengths and weaknesses of the start
techniques identified in the literature. A key point to emerge from this review is that swim-start
techniques have co-evolved (and will likely continue to do so) with such factors as rule changes and
starting block technology. In this respect, variability analysis may be a promising method for
remaining up to date with changes in the sport.
THE START TECHNIQUES
Traditional Start Techniques
Swim-start techniques have evolved over time, and an early technique from 50-60 years ago is the
conventional or arm swing start. Some years later, Zatsiorsky et al. (1979) identified two styles of the
conventional start (with forward arm oscillation and complete oscillation), and Lewis (1980) observed
three types (with arms back, with arms swinging back, and with circular oscillation of the arms).
According to Bowers and Cavanagh (1975) and Lewis (1980), the conventional start allows longer
flight distances than the grab start, largely due to the longer block phase. The conventional start is
still sometimes recommended for relay races, where the increasing arm swing on the block does not
appear to influence the swimmer changeover execution time. Otherwise, it is rarely seen in
competition today. For example, at the Sydney Olympics in 2000, no swimmer used this technique
except in relays (Sanders, 2004).
As the start techniques evolved, the track start appeared and was popularized by Rowdy Gaines,
winner of the 100-m freestyle at the 1984 Olympic Games in Los Angeles. This technique was
borrowed from athletics (track and field), with swimmers putting one foot on the front edge of the
block (track start) instead of two (grab start) (Krüger et al., 2003; Miller et al., 2003; Takeda &
Nomura, 2006). With the track start, swimmers can place the body weight on the front edge (front-
weighted track start) or the back of the block (track start slingshot) (Vilas-Boas et al., 2003, 2000;
Welcher et al., 2008). With the grab start, the hands grip the front edge of the block between the
legs or the front outer edges of the block (Lewis, 1980).
Contemporary Techniques
Some start styles combine several techniques, such as the bunch start, where swimmers place their
feet for a track start and the hands for a conventional start (Ayalon et al., 1975). Galbraith et al.
(2008) studied the effect of arm and hand positions with a modified one-handed track start. Another
example is the tuck start, in which the forward movement of the center of gravity is used by
positioning the compact body while the swimmer grasps the sides of the block (Woelber, 1983). The
purpose of the tuck start is to reduce the time interval between the start signal and entry into the
water (Woelber, 1983). A version of the tuck start, called the handle start, was developed to explore
the effect of placing the center of gravity in the most forward position (Blanksby et al., 2002; Pearson
et al., 1998). This study followed the development of the Anti-Wave SuperBlock with handles on the
sides that the swimmers can hold behind the body (Pearson et al., 1998). However, this type of
starting block even if it was approved by FINA is not the norm in international competition. This is
particularly true since the last regulatory changes.
Future of the Start
By adding an adjustable incline, the Omega kick-start block has become the favored block for the
track start (improving it by adding solid support for the rear foot) (Takeda et al., 2012). Studies
indicate a wide range of behaviors from which swimmers can choose, which helps to explain some of
the difficulty in determining a single “best” technique for optimal performance for various strokes
and body morphologies. In any case, few studies have compared the techniques.
Despite the lack of comparative data, it is reasonable to question whether a single ideal start model
exists. Individuals present with different physical, physiological, and anthropometric characteristics.
Therefore, it is likely that several techniques or combinations of techniques can be used to achieve
expertise in the swim-start, and research has shown that a number of profiles do exist. The concept
of inter-individual variability is particularly relevant to understanding the nature of expertise, but it
complicates the job for coaches, who might very well prefer to have a single profile of a world
champion swim-start that they can encourage their swimmers to work toward.
Importantly, in the few studies comparing start techniques (the grab start and track start), a key
limitation has been that, in almost all cases, the authors did not consider the preferred technique of
the swimmers (Blanksby et al., 2002). Kruger et al. (Krüger et al., 2003) did so (the track start for 2
and grab start for 5), but this information was not included in their analysis of the results. It is
possible that experience with a technique may have an impact on start performance. Vilas-Boas et al.
(2003) and Vantorre et al. (2011) considered this by using a dual approach that mixed the technical
effect and the effect of preference. This distinction between the "technical" and "preferential" effect
is essential.
CONCLUSION
This review has contextualized the analysis of the swim-start in terms of its purpose: to balance
arriving as quickly as possible at the end of the start with the added task of setting up the remaining
portion of the swim. The various phases of the start can be described as a series of compromises that
have to be made. The block phase, for example, requires a compromise between saving time by
leaving the block quickly but only after sufficient time to exert a force against the block which
generates a high enough impulse to drive the swimmer as far as possible and enter the water at high
velocity. The notion of compromise also applies to the aerial phase, with the possibility of choosing a
trajectory for water entry through a hole, a flat trajectory and entry, or a trajectory that lies
somewhere in between. However, a common characteristic of these strategies is to achieve aerial
phases with a segmental alignment when the body breaks the surface of the water. The swimmer’s
goal for the start also affects the choice of strategy to achieve a “good start.” Non-expert swimmers
begin stroking earlier than expert swimmers because they have not yet mastered the phases of the
start well enough for it to provide any advantage over an early stroking commencement. Individual
characteristics also influence how each swimmer optimizes the start phases: sprinters versus long-
distance swimmers, high versus low vertical leaps, large versus small body parts, and so on. In this
sense, variability can be contextualized as functional and not as an error with regard to deviation
from any “only one way” to achieve the best start. The coexistence of several start techniques
position of the feet on the block, arm movement during the flight phase, type of block used, water
depth and swimming stroke confirms the assumption of compromise and adaptation as inherent
challenges for achieving the best swim-start by any individual.
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AUTHORS BIOGRAPHY
Julien VANTORRE
Employment: Part-time lecturer at Rouen University -
Sport Sciences Department.
Degree: PhD.
Research interests: Biomechanics, motor control,
kinesiology applied to swimming.
E-mail: julien.vantorre@univ-rouen.fr
Ludovic SEIFERT
Employment: Lecturer at Rouen University -Sport
Sciences Department.
Degree: PhD.
Research interests: Biomechanics, motor control,
exercise physiology applied to swimming.
E-mail: ludovic.seifert@univ-rouen.fr
Didier CHOLLET
Employment: Full professor, Head of the Sport
Science department at the University Rouen and of the
CETAPS laboratory.
Degree: PhD.
Research interests: Biomechanics, motor control,
exercise physiology applied to swimming.
E-mail: didier.chollet@univ-rouen.fr
KEY POINTS
Swimmers meet two main constraints during the start movement: travelling more distance in
the air (to get less resistance) and rotate to enter properly in the water.
Swim start is a sum of compromises in all parts of it, and swim-start expertise is distinct from
swim stroke expertise corresponding to best ways to manage these compromises.
Variability found is contextualized as having a functional role and operating across multiple
levels of analysis.
... Mills and Gehlson (1996) also measured flight time in their analysis of starts but did not define this phase (9). Highly skilled swim-starts are distinguished in terms of several factors: reaction time from the start signal to the impulse on the block, including the control and regulation of foot force and foot orientation during take-off; appropriate amount of glide time before leg kicking commences; effective transition from leg kicking to break-out of full swimming with arm stroking; overall maximal leg and arm propulsion and minimal water resistance; and minimized energy expenditure through streamlined body position (11). Reaction time was measured as the time between the ''start'' signal and the first movement of the participant using a reaction pad attached to the block (12). ...
... Swimmers who are less expert at the swim start spend more time in this phase and would benefit from training designed to reduce: (i) the time between reaction to the start signal and impulse on the block, and (ii) the time in transition (between gliding and leg kicking, and between leg-kicking and full swimming). Key points swimmers meet two main constraints during the start movement: travelling more distance in the air (to get less resistance) and rotate to enter properly in the water (11). Due to present Federation International de Natation (FINA) starting block facility rule modifications, some researchers and coaches have invested in new technologies to measure the reaction time applied to the swimming starting block during different starting techniques (20,21). ...
... Swim start is a sum of compromises in all parts of it, and swim start expertise is distinct from swim stroke expertise corresponding to best ways to manage these compromises. Variability found is contextualized as having a functional role and operating across multiple levels of analysis (11). More researchers have summarized the current literature regarding the kinematics research progress of swimming start on Omega start block and find the proper swim-start to optimize the swimming performance (7). ...
Article
The purpose of this exploratory descriptive study was to designing and producing a reaction time platform for swimming start block. The participants consisted of 25 male swimmers had been training background at least three years, with mean age of 18.481±2.32 years mean body mass 64.31±7.65 mean height 174±5.39cm and mean body mass index 21.07± 1.97kg/m²; participated in this study, randomly and voluntarily. This device can be installed on the swimming start block. Under the feet of the subject are 6 "batten sensors" that are placed on the front of the platform, and the timer starts to work with device startup bib and is stopped when the swimmer take off from the swimming start block and visible reaction time recorded on the LCD and saved on memory card. The device has two inputs, from the start button and sends data from sensors. The device has two outputs for shows the time and information and connect to the computer via the USB port and sends information to the computer after processing. The device software is written with the programming language C. From experts in swimming, coaches, referees, and swimmers opinions were used to evaluation the validity of device. The Pearson Correlation Coefficient was used to analyze the reliability of the data in two stages by SPSS version 23 statistical software. There was significant correlation coefficient (P = 0.023) between reaction time in the first and second times, There was significant correlation coefficient 47.2 (P = 0.036) between reaction time in the first and third times. There was significant correlation coefficient 65.9% (P = 0.002) between reaction time in the second and third times. Base on the result reaction time in swimming start, there was significant correlation between three times performances. This means with 95% confidence that this device has the reliability and validity required. It is recommended to coaches, referees and researchers use this device in training, competitions and future studies to improve the reaction time of swimmer, reduce the swimming record and referee's error during start.
... Currently, the majority of sports biomechanics research in the field of swimming relies on traditional statistical and theoretical methods. Most of the research on swim starts has aimed to identify the most optimal technique for maximizing performance [6][7][8]. ...
... The segmental angles of the trunk, arm, and thigh to horizontal in the sagittal plane are processed in Kinovea [34]. The start movement in this study is divided into phases according to J. Vantorre et al. [6]. to measure the sagittal angle ( Figure 2) and sagittal angular velocity of the first four phases (block, flight, entry, and glide phases). ...
... The segmental angles of the trunk, arm, and thigh to horizontal in the sagittal plane are processed in Kinovea [34]. The start movement in this study is divided into phases according to J Vantorre et al [6]. to measure the sagittal angle ( Figure 2) and sagittal angular velocity of the first four phases (block, flight, entry, and glide phases). ...
Article
Full-text available
The swimming start, which involves interactions with both water and air, has predominantly been studied primarily in terms of spatio-temporal parameters, while its motor control aspects have received limited attention. This study aims to investigate and compare the coordination patterns between the arm and trunk, as well as the thigh and trunk, in S9, S10, and S12 Paralympic swimmers using the continuous relative phase. The study included twenty-one Paralympic swimmers, and the results showed significant differences (p < 0.05) from spm1d (ANOVA) in both arm-trunk and thigh-trunk CRP among the three classes of swimmers. Significant differences were observed in the arm-trunk CRP during the initial (0–8% of time) and end (30–41% of time) parts of the block phase. Both of these two differences are from the comparison of S10 and S12. The thigh-trunk CRP also showed significant differences at the end of the block phase (35–41% of time) and during the flight phase before entry (58–61% of time). Significant differences were observed in post hoc tests between S9 and S10 and between S12 and S10 for the first significant difference. The second significant difference was found between S12 and S10. The results indicate that Paralympic swimmers classified as S9, S10, and S12 tend to exhibit distinct inter-segmental coordination patterns during the dive start. By recognizing different patterns of motor coordination, coaches and trainers can develop individualized training methods to optimize the start performance for swimmers with different impairments (different classifications) and maximize their competitive potential.
... The individualised techniques can be explained using an ecological dynamics approach where emphasis is placed on Total 1 2 4 5 6 7 8 9 10 11 12 1 1 1 1 1 2 6 2 3 4 7 3 2 2 4 4 1 1 2 5 3 1 4 6 3 3 7 1 3 2 6 8 5 5 9 4 2 2 1 9 10 4 4 the interaction between individuals and their environment (Araújo et al., 2006). These complex interactions lead to the development of individualised motor solutions and movement patterns (Salter et al., 2007;Vantorre et al., 2014). As such, fast bowlers develop individualised techniques that allow them to generate swing. ...
... This is supported by research reporting that fast bowlers use variable movement phase timings while maintaining ball release speed (Andrews et al., 2024). The interactions between performers and task and environment constraints result in intra-athlete technique variability which also increases inter-athlete variation due to the continuous development and refinement of athlete-specific motor solutions and movement patterns (Vantorre et al., 2014). From an ecological dynamics perspective, no one "optimal" technique exists and instead, there are an infinite number of possible movement solutions that could be used by fast bowlers. ...
... The first of these phases is the glide, moment in the swimmer tries to maintain speed without any action to propel the body. For its correct execution it is necessary to achieve and maintain a hydrodynamic, horizontal and progressive position in the water for as long as possible [4][5][6][7], in order to maintain the speed acquired after the impulse of the start or turn [8]. Therefore, it occupies between 10 and 25% of the total time of the test [9] or between 18 the start time [10], becoming a transitional phase before the undulating underwater movement [4], which is crucial to achieve a good performance in the whole underwater swimming. ...
... Only the times of Hay [15] and Wada et al. [17] were close to the crawl and butterfly times analysed, together with those of Pearson et al. [12], which are in the same swimming category despite the methodological differences (start vs. push-off start). In terms of distance, the results of other studies analysing gliding and turning with the pronated monofin [22] showed lower values than ours, because the swimmers performed a short propulsion, thus reducing their gliding [3,4,8,17,24]. However, only the speeds found in a study analysing crawl turns [19] were close to ours, and other studies have shown even higher values, regardless of the category of swimming analysed (national, sub-elite and elite) [14,33]. ...
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The aim of the study was to analyze the kinematic parameters of the push-off start during the underwater glide in competitive swimmers. 74 swimmers participating in the Spanish Championships were filmed and analyzed by DLT-2D photogrammetry after the push-off start in crawl, backstroke and butterfly. Between genders there were differences in distance and speed. Male swimmers covered greater distances (1.37±0.06 vs 1.20±0.05 m, η2 = 0.02, F = 3.85, p = 0.05) and were faster (2.36±0.03 and 2.08±0.03 m/s, η2 = 0.14, F = 36.14, p<0.001) than female swimmers. Between strokes there were greater differences in time (η2 = 0.06, F = 6.76, p = 0.00) and distance (η2 = 0.38, F = 67.08, p< 0.001), than in speed (η2 = 0.05, F = 5.63, p< 0.001). During the backstroke, less time (0.50±0.04 s) and distance (1.01±0.07 m) were used, being the slowest style (2.12±0.04 m/s). In butterfly, less time (0.63±0.04 s) and distance (2.25±0.04 m) were used, while crawl was the fastest (2.30±0.04 m/s). These results allow us to characterize the underwater glide phase and provide useful data for both competitive swimmers and coaches to improve performance.
... Based on correlations with 5-m start times, successful relay swimmers at the national level should have high take-off velocities, a high centre of mass position at take-off, long entry distances, and short change-over times . To this end, preparatory movements on the block should be long enough to anticipate the wall contact of the incoming swimmer and maximise the swimmer's impulse (Vantorre et al., 2014). The step technique enables swimmers to apply horizontal forces to the block and achieve a certain forward velocity prior to the leg extension phase (Takeda et al., 2010). ...
Article
Purpose: To compare the kinematic profile of 2 underwater pullout breaststroke techniques. Methods: Sixteen swimmers (9 men, 20.67 [2.71] y old; 7 women, 18.86 [0.83] y old) performed 3 × 25-m breaststroke using 2 pullout breaststroke techniques: Fly-Kick first and Combined. A speedometer was used to assess the peak and the mean velocity during the glide, propulsion, and recovery phases of both techniques, as well as for the total underwater sequence. The underwater distance was retrieved from video footage and was considered for each pullout technique. The range of motion of the knee during the fly-kick was also retrieved, and the time to complete the 25 m was considered the performance outcome, accompanied by the mean velocity, stroke rate, stroke length, and stroke index. Results: Velocity-time series showed different profiles between pullout techniques (P ≤ .05) mostly in the glide and propulsion phases for males and females, respectively. The mean velocity of 25 m was shown to be greater in females when using the Fly-Kick first technique (P = .05, d = 0.36). Greater values in total underwater distance and knee range of motion were also observed for this technique in both cohorts. Conclusions: Female swimmers presented a higher performance when using the Fly-Kick first technique. Different kinematic profiles arise when swimmers use different underwater pullout techniques where the Fly-Kick first may allow them to reach higher kinematical standard.
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Background The aim of this study is to investigate the acute effects of anodal transcranial direct current stimulation (tDCS) on reaction time, response inhibition and attention in fencers. Methods Sixteen professional female fencers were recruited, and subjected to anodal tDCS and sham stimulation in the primary motor area (M1) one week apart in a randomized, crossover, single-blind design. A two-factor analysis of variance with repeated measures was used to analyze the effects of stimulation conditions (anodal stimulation, sham stimulation) and time (pre-stimulation, post-stimulation) on reaction time, response inhibition, and attention in fencers. Results The study found a significant improvement in response inhibition and attention allocation from pre-stimulation to post-stimulation following anodal tDCS but not after sham stimulation. There was no statistically significant improvement in reaction time and selective attention. Conclusions A single session of anodal tDCS could improve response inhibition, attention allocation in female fencers. This shows that tDCS has potential to improve aspects of an athlete’s cognitive performance, although we do not know if such improvements would transfer to improved performance in competition. However, more studies involving all genders, large samples, and different sports groups are needed in the future to further validate the effect of tDCS in improving the cognitive performance of athletes.
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The introduction of the Anti Wave Olympic 2000 Start Block with side handles has raised the possibility of a faster start than the currently favoured grab start technique. Eighteen state level age group swimmers (mean age 14.8 ± 3.57 yrs) performed two grab start dives and two handle start dives. Data were collected from a start block instrumented for force measurement and synchronised with a starting signal, finishing gate, digital timing apparatus and above and below water video recordings. Variables measured included block, flight and glide times; total time to 7 m; take off force; take off, flight and entry characteristics. For the handle start, block time was significantly faster (0.04 s), horizontal hip position at 'set' was 0.2 m further forward and the maximum force vector angle was 5° shallower. The total time to 7 m was not significantly different between dive types. All other dive performance variables, land based jumps and anthropometric data showed no significant differences. The dissipation of the initial advantage off the blocks, when further sources of variance were added, reflected previous research on grab starts. Further research using longer practice periods, more elite subjects, alternative handle placement and identifying optimal joint angle initial positions is recommended.
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Dive starts generate the fastest velocities in swimming races. With 50m events lasting for just over 20s, a starting gain of 0.1s could very likely mean the difference between winning and losing. As the length of races increases, any proportionate gain from the start diminishes, but remains important. Research remains ambivalent regarding the complex manoeuvres required for an effective start and, despite the introduction of several new techniques; none have demonstrated superiority.Turning generates the second fastest velocities in swimming and can represent up to 30% of distance covered. Efficient turns increase in importance with the race distance;especially in short course pools. Changes have occurred with turn techniques but superiority is again equivocal. However, rules no longer requiring hand touches have altered freestyle and backstroke turns; and underwater kicking has altered turns for all four competitive strokes.This chapter reviews sport science research of swim starts and turns to provide evidence based information that coaches could use with swimmers.