Estimated Effect of Monofin Stiffness on Sports Performance in

Marathon Swimmers

Alexander Bolotin

, Vladislav Bakayev

and Pavel Dudchenko

Peter the Great St. Petersburg Polytechnic University, 29 Politekhnicheskaya St., St. Petersburg, Russia

Tula State Lev Tolstoy Pedagogical University, Tula, Russia

Keywords: Marathon Swimming with Fins, Monofin Stiffness, Training Accounting for Monofin Stiffness, Sports

Performance Efficiency.

Abstract: The study conducted has confirmed that the techniques and methods for training marathon swimmers in fins,

tailoring the monofin stiffness to the individual capabilities of the athletes, play a major role in increasing

the efficiency of training for competitions. The athletes can reliably achieve better results in the training

process and in competitions. Training sessions with monofin stiffness taken into account have been found to

have a higher efficiency. Our studies established that the kinematic characteristics undergo certain changes,

some of them rather considerable. Using the monofin with the stiffness corresponding to individual

capabilities of marathon swimmers allowed increasing the intracyclic speed of the strongest athletes from

2.53 m/s to 3.01 m/s (at the end of the experiment), i.e., the speed increase amounted to 19%. This is also

confirmed by the increased average speed of distance swimming: 3.02 m/s and 3.48 m/s respectively, which

is an increase of 17%. The study showed that successfully training athletes for competitions largely depends

on accounting for the individual characteristics of muscular activity in marathon swimmers and the stiffness

of the monofin. We have discovered that higher elasticity of an athlete's muscles should correspond to

smaller monofin stiffness. The article presents the results of assessing the effect of monofin stiffness on the

performance of marathon swimmers.

1 INTRODUCTION

Significance. Open-water marathon swimming with

fins is a strenuous activity demanding high levels of

physical fitness. For best results, the stiffness of the

monofin should closely match the athlete's muscle

structure. Monofin swimming provides an increase

in speed due to:

- increased surface area of the monofin, generating

large thrust in the water;

- large group of muscles of the athlete's legs, back

and abdomen working simultaneously;

- wave-like bending and oscillatory movements

made by the athlete's body and the monofin,

which are more efficient from a hydromechanical

standpoint.

Therefore, tailoring the stiffness of the monofin as

well as matching it to the athlete's specific muscle

structure and fitness levels is a major goal for

coaches and marathon swimmers.

Analysis of the literature showed that the

majority of studies on training of marathon

swimmers in fins do not provide sufficient data on

selecting monofin stiffness in accordance with

individual capabilities of an athlete. This greatly

limits the sports performance. Furthermore, methods

for improving specific and general endurance in

marathon swimmers in fins accounting for monofin

stiffness have been developed insufficiently this far.

The existing system for training marathon swimmers

in fins for competitions does not offer satisfactory

options accounting for monofin stiffness and

adapting it to the individual characteristics of the

athletes' muscular activity during practice The

system's main drawback is in the general approach

to training of marathon swimmers in fins, failing to

consider the athletes' individual skills. This does not

allow to effectively increase the general endurance

and speed endurance in marathon swimmers in fins,

which are imperative for improving the overall

sports performance (Alpatov et al., 2020, Bakayev,

2015, Clemente-Suárez et al., 2017, Hue et al., 2006,

Rejman and Borowska, 2008, Rejman, 2013,

Pendergast et al., 2003).

Bolotin, A., Bakayev, V. and Dudchenko, P.

Estimated Effect of Monoﬁn Stiffness on Sports Performance in Marathon Swimmers.

DOI: 10.5220/0010656600003059

In Proceedings of the 9th International Conference on Sport Sciences Research and Technology Support (icSPORTS 2021), pages 111-115

ISBN: 978-989-758-539-5; ISSN: 2184-3201

111

Thus, assessing the influence of monofin

stiffness on sports performance in marathon

swimmers is of great practical importance for

improving the quality of the training process.

Goal: to evaluate the degree of influence that

monofin stiffness has on the performance of

marathon swimmers in order to improve the quality

of the training process.

2 MATERIAL AND METHODS

The present study considers modern methods for

assessing the degree of influence of monofin

stiffness on the performance of marathon swimmers.

The main method is predictive simulation in

accordance with modern methods for assessing the

properties of materials from which the monofin is

made and the muscular structure of swimmers

competing in open water. Analysis of modern

methods for assessing the degree of influence of

monofin stiffness on the performance of marathon

swimmers has been carried out.

3 RESULTS AND DISCUSSION

The monofin has come a long way to achieve its

overwhelming popularity in numerous studies of

marathon swimmers. First, the monofin has driven

out the elongated bi-fins in middle and long

distances. Currently, all the leading marathon

swimmers in the world compete in monofins

(Takeda et al., 2020, Ng et al., 2019, Ganapolsky et

al., 2019, Bolotin and Bakayev, 2017, Oshita et al.,

2013, Vercruyssen et al., 2012, Bolotin and

Bakayev, 2020).

Based on the goals of the study and the specifics

of open-water marathon swimming, the athletes’

physiology and the operating principles of the

monofin, we formulated the following objectives:

1. Determine the design parameters of monofins.

2. Understand the relationships of these parameters

with the performance of marathon swimmers and

anthropometric characteristics of athletes.

3. Find ways to improve the monofin stiffness

based on the requirements of hydro-bionics and

individual capabilities of marathon swimmers.

4. Develop a technique for calculating the monofin

stiffness based on the requirements of hydro-

bionics and individual capabilities of marathon

swimmers.

The following was established based on the

objectives posed:

- monofin should be shaped as a semi-ellipse,

avoiding sharp angles and bends of the side

edges;

- area S

of monofin surface on one side was

chosen from the ratio of the area S

of the

athlete's body to S

: S

= 0.2l S

;

- relative elongation of the monofin equals

Z=w/S

, where w is the width of the monofin, in

the range of 1.5 < Z < 1.7;

- smoother profile creates a uniform distribution of

stiffness along the entire length and area as a

whole, increasing the speed of the athletes.

Monofin stiffness was further enhanced by air

cavities specially created inside the foot pockets. Air

or water (preferably salt water) was pumped into

these pockets through nipple valves. The stiffness of

the foot pockets and angle selected for the pressed

wedge should ideally eliminate or at least minimize

the angle between the longitudinal axes of the shins

and the blade in a streamlined position of the

athlete's stretched body with the monofin on the

water surface.

Practically excluding the foot, which is in this

case, a rather ineffective link of the lower limb, from

swimming motion, makes the lower leg a powerful

lever, providing a more efficient transfer of the

energy generated by bending and oscillating

movements to the monofin to achieve greater

swimming speed.

Immobilizing the feet and symmetric (relative to

shins) oscillations of the monofin blade in the

vertical plane bring the kinematics of the underwater

swimmer’s movements even closer to swimming of

aquatic animals (cetaceans, in particular), whose

vertical oscillations of the tail fin are symmetric

relative to the body axis. This produces a self-

oscillatory swimming mode, which is the most

resource-efficient.

The second feature of the monofin is the

increased volume of the blade profile, with the

stiffness varying based on the individual capabilities

of marathon swimmers (Figure 1).

Our studies established that the kinematic

characteristics undergo certain changes, some of

them rather considerable. This refers, first of all, to

intracyclic (per cycle) speed V

as an integral

indicator of the relationships between all other main

parameters: time T

of the movement cycle, ‘step’

, and swimming pace N.

Using the monofin with the stiffness

corresponding to individual capabilities of marathon

swimmers allowed increasing the intracyclic speed

icSPORTS 2021 - 9th International Conference on Sport Sciences Research and Technology Support

112

Figure 1: Schematic view of monofin: photo (a); sections (b, c); position of feet in the pockets, shown conventionally (d).

Table 1: Comparative assessment of parameters in swimming with monofins of different stiffnesses for strongest marathon

swimmers.

Leading athletes of the

Russian Federation

Kinematic characteristics

(m) L

(m) V

(m/s) N (1/s)

Amplitude (span), m

Athletes using a ‘rigid’ monofin

(n=7)

Χ 0.49 1.21 2.51 2.3 0.11 0.12 - 0.23 0.28 0.47

σ 0.04 0.05 0.17 0.19 0.03 0.03 - 0.03 0.02 0.03

Athletes using a ‘soft’

monofin (n=7)

Χ 0.41 1.29 3.02 2.5 0.12 0.15 - 0.32 0.37 0.53

σ 0.04 0.06 0.23 0.24 0.03 0.03 - 0.05 0.04 0.03

Note: T

- movement cycle time, L

movement step, movement step, V

- intracycle velocity, N - pace of movement, A

- amplitude of the

hands, A

- knee vibration amplitude, A

- ankle vibration amplitude, A

- amplitude of oscillation of the trailing edge of the monofin.

of the strongest athletes from 2.53 m/s to 3.01 m/s

(at the end of the experiment), i.e., the speed

increase amounted to 19%. This is also confirmed by

the increased average speed of distance swimming:

Estimated Effect of Monoﬁn Stiffness on Sports Performance in Marathon Swimmers

113

3.02 m/s and 3.48 m/s respectively, which is an

increase of 17%. This increase in speed is very

substantial for the longest distance (6 km).

Since the limits (quantitative and qualitative) for

functional training of athletes (amount and intensity

of training) have long been reached, this increase in

the long-distance swimming speed of marathon

swimmers depends on the monofin stiffness selected

based on the individual capabilities of marathon

swimmers.

Analyzing the oscillation amplitudes at the points

of the ‘athlete–monofin’ system (Table 1), we can

observe an increase in all oscillation amplitudes in

marathon swimmers, starting from the hands (A

) to

the trailing edge of the monofin (A

Large amplitudes characteristic for the modern

swimming techniques, especially the oscillation

amplitudes of knee (A

) and ankle (A

) joints, as

well as the trailing edge of the monofin (A

) are

explained, in our opinion, by only one factor, which

was already discussed above: a new, longer lever

connected to the monofin, i.e., the athlete's shin.

This is explained by:

1. Increase in the level of functional training, so

that modern marathon swimmers can ‘rotate’ the

heavier monofin with a higher frequency (rate)

of oscillations.

2. Self-oscillatory mode, where the muscular effort

corresponds to the stiffness of the monofin. This

is reported by the athletes themselves based on

their sensations and experience in overcoming

the distance. Marathon swimmers use the inertia

of the monofin oscillations to switch to self-

oscillatory mode with a quick pace.

3. Optimization and coordination of trajectories of

points in the body and the monofin during

bending and oscillatory movements of marathon

swimmers.

4 CONCLUSIONS

1. The monofin has evolved into a better and more

efficient accessory, corresponding to the

individual capabilities of marathon swimmers,

providing an increase in the athletes' swimming

speed.

2. The monofin with optimal stiffness provides a

‘new link’ in the athletes' lower limbs, that is, the

feet with the monofin, which act as a single unit,

optimal in terms of the muscular structure of

marathon swimmers.

З. The ‘new link’ in the lower limbs helped adjust

the swimming kinematics, optimizing the

technique for bending and oscillatory movements

of marathon swimmers, with a self-oscillatory

mode emerging, consequently yielding an

increase in speed.

Research on developing new types of monofins with

stiffnesses matching the individual capabilities of

marathon swimmers should involve specialists in the

field of sports physiology, programming and sports

metrology.

REFERENCES

Alpatov, V.N., Ganapolsky, V.P., Rodichkin, P.V.,

Ganapolskaya, M.V. (2020). Mathematical model to

predict painless decompression illness in competitive

diving. Teoriya i Praktika Fizicheskoy Kultury, (11),

pp. 32-34.

Bakayev, V. (2015). Determining the significance of

practical military skills applied by the special purpose

regiments of the Internal Troops of the Russian

Ministry of Internal Affairs to deliver combat

objectives. Journal of Physical Education and Sport,

15(4), pp. 615-618.

Bolotin A., Bakayev V. (2017). The differences in

response of the respiratory system of long and middle-

distance runners and their influence on recovery rate.

Journal of Physical Education and Sport, 17(4),

pp.2443-2446. DOI: 10.7752/jpes.2017.04272.

Bolotin, A., and Bakayev, V. (2020). Comparative

Analysis of Peripheral Blood Circulation Parameters

in Long-Distance Swimmers at Middle Altitude and

Under the Conditions of a Hypoxic Gas Environment.

Sport Mont, 18(2), pp. 113-115.

Clemente-Suárez, V. J., Dalamitros, A., Ribeiro, J., Sousa,

A., Fernandes, R. J., & Vilas-Boas, J. P. (2017). The

effects of two different swimming training

periodization on physiological parameters at various

exercise intensities. European journal of sport

science, 17(4), 425–432.

https://doi.org/10.1080/17461391.2016.1253775

Ganapolsky, V.P., Matytsin, V.O., Rodichkin, P.V.,

Yakovlev A.V. (2019). Efforts to Improve physical

work capacity of athletes based on interval hypoxic

training. Teoriya i Praktika Fizicheskoy Kultury, (10),

pp. 18-19.

Hue, O., Galy, O., Blonc, S., & Hertogh, C. (2006).

Anthropometrical and physiological determinants of

performance in French West Indian monofin

swimmers: a first approach. International journal of

sports medicine, 27(8), 605–609.

https://doi.org/10.1055/s-2005-865856

Ng, F., Wen Yam, J., Lum, D., & Barbosa, T. M. (2019).

Human thrust in aquatic environment: The effect of

post-activation potentiation on flutter kick. Journal of

advanced research, 21, 65–70.

https://doi.org/10.1016/j.jare.2019.10.001

icSPORTS 2021 - 9th International Conference on Sport Sciences Research and Technology Support

114

Oshita, K., Ross, M., Koizumi, K., Tsuno, T., & Yano, S.

(2013). Gender difference of aerobic contribution to

surface performances in finswimming: analysis using

the critical velocity method. Asian journal of sports

medicine, 4(4), 256–262.

https://doi.org/10.5812/asjsm.34244

Pendergast, D. R., Mollendorf, J., Logue, C., & Samimy,

S. (2003). Evaluation of fins used in underwater

swimming. Undersea & hyperbaric medicine: journal

of the Undersea and Hyperbaric Medical Society, Inc,

30(1), 57–73.

Rejman, M., & Borowska, G. (2008). Searching for

criteria in evaluating the monofin swimming turn from

the perspective of coaching and improving technique.

Journal of sports science & medicine, 7(1), 67–77.

Rejman M. (2013). Analysis of Relationships between the

Level of Errors in Leg and Monofin Movement and

Stroke Parameters in Monofin Swimming. Journal of

sports science & medicine, 12(1), 171–181.

Takeda, T., Sakai, S., & Takagi, H. (2020). Underwater

flutter kicking causes deceleration in start and turn

segments of front crawl. Sports biomechanics, 1–10.

Advance online publication. https://doi.org/10.1080/

14763141.2020.1747528

Vercruyssen, F., Boitel, G., Alberty, M., Nesi, X.,

Bourdon, L., & Brisswalter, J. (2012). Influence of

kick frequency on metabolic efficiency and

performance at a severe intensity in international

monofin-swimmers. Journal of sports sciences,30(10),

1055–1061. https://doi.org/10.1080/02640414.2012.

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