PREDICTION MODEL OF INFLUENCE OF FORCE ON LAND AND PERFORMANCE IN FIN SWIMMING , A PILOT STUDY

e purpose of this research is the determination of a prediction model that could predict 50m and 100m n swimming results on surface. e sample of this research consisted of 9 n swimmers of competitive level. All participants swam 50 and 100 meters on the water surface with mono n and a snorkel with maximum intensity. In two next sessions, force of the leg extensors and ankle extensors were measured in the workout gym with a dynamometer. e results of this study concluded in a potential statistical signi cance of regression analysis for 50m n swimming with snorkel on the surface of the water. Relative force values of ankle and leg extensors are better predictors of 50m n swimming. No similar results were found for 100m n swimming. ese ndings probably suggest that in shorter distance of 50m n swimming, force variables of extensor muscles play a greater role in comparison to longer distance of 100m n swimming. e measurement of force of legs in n swimming is of particular interest because legs are mostly responsible for the propulsion in n swimming and should further be studied with other force protocols, di erent exercises and larger sample.


INTRODUCTION
Mono n swimming is a movement of the swimmer's body through water, in a wavy line, in which the movement of legs is maximal, while the movement of the upper body is minimal.To achieve this, the body must be aligned with the arms stretched above his head while hands crosslinked (the inner part of the hands facing the bottom of the pool).Respiration is done by ventilation (snorkel) through the mouth which is xed to the head.Fin swimming is a sport of speed, and it takes place on the water surface and underwater.In n swimming speeds of 3,89m / s are achieved (Vogel, 1994).e movement of the swimmer resembles the movement of dolphins and the propulsion needs a movement of the entire body (Videler, 1981).e arms and hands are not used for the propulsion of the body (Gautier et al., 2004).
Di erent distances and di erent types of ns and equipment are used in competition.Clearly, improved materials of ns and equipment are generally responsible for the improved performance, despite the fact that the design of mono n is still empirical (Bideau et al., 2002).
e most signi cant contribution to the development of high speed is derived from the construction of the mono n which was adjusted to competition and training program (Zamparo, Prendergast, Termin & Minetti, 2002).
Researches on n swimming were intensi ed after the invention of the mono n and the new method of propulsion in water (Pendergast, Tedesco, Nawrocki & Fisher, 1996).e movement with mono n as a new way to swim forced the researchers to turn their interest in n swimming as a particular sport.
Scienti c studies on the preparation of n swimming athletes appeared in the decade of 1980 (Popov, 1982;Zammartini, 1986).Few studies exist on the e ects of training in the art of swimming.
Apart from the necessary qualitative execution of technical elements of swimming (Dopsaj, et al 2000b), characteristics of force provide important information and play a decisive role in the competition of 50 and 100 meters n swimming.Propulsion bears on the vertical displacement of the whole body.e use of the upper body is forbidden for propulsion purposes.e vertical displacement of the body during the stroke cycle has been described as wave-like (Ungerechts, 1982).Since such motion could be characterized by speci c amplitudes of oscillations.Such oscillations were also speci ed by a particular frequency and phase relationship (Sanders et al., 1995).
Another study revealed the e ect of the monon shape on the propulsive forces by analyzing the change in the swimmer's velocity over one cycle of the mono n's motion (Tamura et al., 2002).
Measurement of muscle force is performed using a dynamometer, and in the attempt to obtain the most accurate data, precision electronic devices are applied.In the measurement of force of various muscle groups using a dynamometer, there is a different development trend.e di erence of athlete's strength is changing through the years.
Mono n swimming is very interesting concerning the force application.e swimmer and mono n share a mechanical interaction, that is, the swimmer can transmit the force to the mono n to drive it, and the mono n returns the reaction to the swimmer. is interactive relationship determines the total swimming performance (Nakashima, Suzuki & Nakajima, 2010).e present research is an attempt to measure the force out of the water, of muscle groups that play an important role in n swimming.e purpose of this research was the determination of force parameters of selected muscle group that, should predict of performance of 50m and 100m n swimming

Sample
e sample consisted of 9 athletes of n swimming and competitive level, age: 17.0 ± 0 years, height: 176 ± 5cm and weight: 72 ± 5kg.eir training age was 5 years.e study was approved by the Ethical Committee of Athens University.

Procedures
e measurements were performed in an outdoor swimming pool 50m length and 3m depth (Olympic size).e water temperature was 26 o .e measurements took place at midday between 12:00 to 14:00, because this was the time of their training session.
All measurements were made 15 days before the main competition of the summer cycle, in random order.Body height (cm) and weight (kg) were measured with minimum athletic attire (swimsuits) in the gym of the swimming pool.
e athletes were informed about the purpose of the investigation, the potential risks and procedures of measurements, and they gave their written consent with their parents.All swimmers involved in daily training lasting two hours and at least ve days per week.
In the rst session swimmers made the same warm up of 1000m under the guidance of their coach.Ten to een minutes a er, they swam with maximum intensity the distance of 50 meters on the surface of the water with a ventilator (snorkel) and the mono n adjusted to their feet.In the next session on a di erent day, they swam the distance of 100 meters with the same conditions.Before each test, heart rate was measured to reassure that participants have a heart rate of low and equal level.
Both measurements started from the starting block.Immediately a er the e orts, heart rate and performance time were recorded with a stopwatch (Seiko Water Resistant 10bar S140).
In the last session, on di erent day in two subsequent measurements, the force of the ankle extensor (Image 1) and the leg extensors (Image 2) were recorded with a dynamometer (IMADA) in the gym where the dry land workout takes place.
For the measurement of isometric force of ankle extensors, the swimmers were sitting on a chair and were asked to li their ankles against a thick wooden platform that was xed on their legs and connected to the dynamometer.e angle of both knees was same for all participants, 90 degrees.
For the second measurement of isometric force of leg extensors, swimmers were standing with their knees slightly bend and with their hands straight next to their hips holding a handle connected to the dynamometer and were asked to straighten their knees.
-Fmax of leg extensors-average of maximum muscle pulling force (peaks) for leg extensors, given in N. -Fmax of ankle extensors-average of maximum muscle pulling force (peaks) for ankle extensors, given in N. -Frel of leg extensors-relative force for ankle extensors.-Frel of ankle extensors--relative force for ankle extensors.

Statistical analysis
All data went through a descriptive statistical analysis.For the analysis of force and swimming performance multiple regression analysis was applied in order to determine the variables that best describe 50m and 100m n swimming.Values are expressed in mean values and standard deviations.
e signi cance level for all parameters was set at p <0.05.Data analysis was done with the statistical program SPSS 22.

RESULTS
Descriptive statistics of the variables are shown in Table 1.Multiple regression model explained 64.1% of dependent variable (Adj.R 2 = 0.641) ' n swimming time at 50m' , (50m n swimming average results = 19.8878± 0.9231secs).Regression model for 50m was not generally statistically signi cant (Sig..085).We could say that these results are potentially statistically signi cant because p is less than 0.100, which means statistical probability is 91.5%.e results of the multiple regression analysis concerning 50m n swimming on surface are shown in Table 2.All of the data were automatically stored in the computer memory using the appropriate «Imada so ware», connected with the dynamometer (Pro-Ing system, Serbia).For the analysis of the results, maximum force of each measurement was used.Furthermore, relative value of isometric force was calculated and used in the prediction model of 50m and 100m n swimming.Relative force values (Frel ) were calculated according to the maximum values obtained in previous Fmax values divided by body weight.

Variables
Variables that accrued of the measurements and calculation were: Furthermore, at partial level all single variables explain statistically signi cantly 50m n swimming results at 0.015, 0.019, 0.016 and 0.020 p level, respectively, but as a group of variables no general signicant explanation can occur.
e Prediction Model Equation for 50m Fin swimming time is: As shown by the analysis of the results, relative results (Frel) have greater in uence at 50m results than absolute results (Fmax).
Concerning the results of 100m n swimming with snorkel, no statistical signi cance occurred.None of the force variables describe su ciently the dependent variable '100m time in n swimming' , all four variables were removed with p values .981,.929,.809,.537,respectively for each model.Furthermore, no signi cant results were presented in partial level.

DISCUSSION
e results of this study concluded in a potential statistical signi cance of regression analysis for 50m n swimming with snorkel on the surface of the water.Relative force values of ankle and leg extensors are possible predictors of 50m n swimming.e prediction model that occurred is: No similar results were found for 100m n swimming.ese ndings probably suggest that in shorter distance of 50m n swimming, force variables of extensor muscles play a greater role in comparison to longer distance of 100m n swimming.
Previous study concerning classical swimming (Dopsaj et al., 2004) found that explosiveness of back, feet and ankle extensors can be signi cant predictors of performance of 50 and 100m swimming.
In the eld of mono n swimming, there is not enough bibliography that has to do with dry land measurements of force.Most of the research concerning mono n swimming has to do with kinematic analysis of the movement of the n and the swimmer (Rejman, 2013; Rejman, Klarowicz & Zaton, 2012).
Further research is needed in order to determine a procedure that will control swimmer's tness levels on land not only to enable more accurate management of the training process either in water or on land, but also to enhance the e ectiveness of training and raise the competitive tness levels in sprint mono n swimmers.

CONCLUSION
Limitations of this research (sample size) could not permit statistical signi cance of the regression model for 50m n swimming, whereas all force parameters resulted in signi cant predictors in partial level.
Lack of signi cant results in 100m n swimming in this study emphasize the need of further research in dry land measurements connected to mono n swimming.
Such a measurement, which can yield high quality information on an athlete's actual level of competitive tness, is very important both to the trainer and the athlete, as to the control of the e ects of the training methods employed in the preparation period, and to the tness status on land with respect to explosiveness, which is an essential part of training technology.

MODELO DE PREDICCIÓN DE LA INFLUENCIA DE FUERZA EN LO SECO Y EL RENDIMIENTO EN LA NATACIÓN CON ALETAS -ESTUDIO PILOTO Resumen
El objetivo de la presente investigación es determinar el modelo de predicción que podría prever los resultados de natación con aletas a 50 m y a 100 m.La muestra de esta investigación han sido los 9 nadadores con aletas a nivel de competencia.Todos los participantes nadaron con la intensidad máxima con aletas mono n con tubo respetador a 50 y a 100 metros en la super cie del agua.En dos siguientes fases la fuerza de los músculos extensores de piernas y de los musculáis extensores de pierna inferior se ha medido en el gimnasio por dinamómetro.Los resultados de esta investigación han llevado hasta la conclusión sobre la posible importancia estadística del análisis de regresión de la natación con aletas a 50 m con tubo respirador en la super cie del agua.Los valores de la fuerza relativa de los músculos extensores de la pierna inferior y de la pierna son mejores predictores para la natación a 50 m con aletas.Los resultados parecidos no se han obtenido en la natación con aletas a 100 m.Estos descubrimientos probablemente sugieren que a distancias más cortas en la natación con aletas a 50 m las variables de fuerza de los músculos extensores juegan un mayor papel en comparación con la natación a una mayor distancia, natación con aletas a 100 m.La medición de la fuerza de las piernas en la natación con aletas tiene una importancia especial teniendo en cuenta que las piernas en general son responsables para la propulsión en la natación con aletas y hace falta seguir investigando con otros protocolos de fuerza, distintos ejercicios y en una muestra mayor.

ЛИТЕРАТУРА MODELO DE PREDICCIÓN DE LA INFLUENCIA DE FUERZA EN LO SECO Y EL RENDIMIENTO EN LA NATACIÓN CON ALETAS -ESTUDIO PILOTO Resumen
El objetivo de la presente investigación es determinar el modelo de predicción que podría prever los resultados de natación con aletas a 50 m y a 100 m.La muestra de esta investigación han sido los 9 nadadores con aletas a nivel de competencia.Todos los participantes nadaron con la intensidad máxima con aletas mono n con tubo respetador a 50 y a 100 metros en la super cie del agua.En dos siguientes fases la fuerza de los músculos extensores de piernas y de los musculáis extensores de pierna inferior se ha medido en el gimnasio por dinamómetro.Los resultados de esta investigación han llevado hasta la conclusión sobre la posible importancia estadística del análisis de regresión de la natación con aletas a 50 m con tubo respirador en la super cie del agua.Los valores de la fuerza relativa de los músculos extensores de la pierna inferior y de la pierna son mejores predictores para la natación a 50 m con aletas.Los resultados parecidos no se han obtenido en la natación con aletas a 100 m.Estos descubrimientos probablemente sugieren que a distancias más cortas en la natación con aletas a 50 m las variables de fuerza de los músculos extensores juegan un mayor papel en comparación con la natación a una mayor distancia, natación con aletas a 100 m.La medición de la fuerza de las piernas en la natación con aletas tiene una importancia especial teniendo en cuenta que las piernas en general son responsables para la propulsión en la natación con aletas y hace falta seguir investigando con otros protocolos de fuerza, distintos ejercicios y en una muestra mayor.

Table 2 .
Regression analysis for 50m n swimming results.