Biomechanics and Medicine in Swimming XI

More documents

Recommendations

Info

The Acute Effect of Front Crawl Sprint-resisted Swimming on the Direction of the Resultant Force of the Hand Gourgoulis, V. 1 , Aggeloussis, n. 1 , Mavridis, G. 1 , Boli, A. 1 , toubekis, A.G. 2 , Kasimatis, P. 1 , Vezos, n. 1 , Mavrommatis, G. 1 1 Democritus University of Thrace, Komotini, Greece 2 Kapodistrian University of Athens, Athens, Greece The aim of the study was to investigate the acute effect of front crawl sprint-resisted swimming on the direction of the resultant force of the hand. Five female swimmers swam 25 m with maximal intensity with and without added resistance. The underwater motion of the hand was recorded using 4 cameras (60 Hz) and the Ariel Performance Analysis System was used for the digitization. The results showed that the magnitude of the drag and lift forces, as well as the magnitude of the resultant force was not modified significantly during resisted swimming. However, the angle formed between the resultant force and the axis of the swimming propulsion was decreased significantly in the pull phase. Thus, it could be speculated that sprint-resisted swimming could contribute to the learning of a more effective application of the propulsive forces. Key words: front crawl, resisted swimming, resultant force. IntroductIon In front crawl swimming, the propulsive forces generated mainly from the arms. The way swimmers use their arms to apply these forces is decisive for effective swimming propulsion (Arellano, 1999). The resultant propulsive force produced by a swimmer’s hand is a combination of two types of propulsive forces: the drag force and the lift force. For effective swimming propulsion the resultant of these two forces should be aimed, as much as possible, in the swimming direction (Rushall et al., 1994; Schleihauf, 2004; Toussaint et al., 2000). In addition, in front crawl swimming, which is a stroke with alternate arm movement, it is necessary to avoid significant deviations of the resultant force vector from the swimming direction, since this may cause undesirable sideways and vertical deviations of the body, increasing the resistive forces (Vorontsov & Rumyantsev, 2000). Moreover, it is considered that training methods such as sprintresisted swimming where the swimmers swim against a resistance in addition to the natural water resistance are more effective for the improvement of the swimming performance than dry land training methods (Girold et al., 2007; Llop et al., 2006; Williams et al., 2001). In the past, the acute effect of sprint-resisted swimming has been investigated in various kinematic characteristics of the stroke, such as the time of the underwater motion of the hand, the velocity of the hand, its medial – lateral displacements, the stroke rate, the stroke length, the stroke depth and the swimming velocity (Maglischo et al., 1984; Maglischo et al., 1985; Williams et al., 2001). However, there is a lack of data regarding the effect of the sprint-resisted swimming on the direction of the resultant force. It could be speculated that, if during sprint resisted swimming the angle between the resultant force vector and the axis of swimming propulsion is decreased, then this training method could probably contribute to the learning of a more effective application of the propulsive forces. Therefore, the aim of the present study was to examine the acute effect of front crawl sprintresisted swimming on the direction of the resultant force of the hand. Methods Five female competitive swimmers participated in the study (age: 20.4 ± 6.1 years, height: 1.73 ± 0.03 m, body mass: 59.1 ± 6.67 kg, best performance in the 100 m front crawl swimming: 62.59 ± 2.88 s). Each swimmer swam in randomized order two trials of 25 m front crawl with chaPter2.Biomechanics maximal intensity. One of the trials was performed without added resistance and the other one was performed with an added resistance. A bowl with a diameter of 32 cm and a capacity of 6 l was used as added resistance. The bowl was pulled by its convex side and it was tethered on a belt, which was around the waist of each swimmer, with a 1.5 m long elastic tube (Mavridis et al., 2006). All trials were executed using a sixbeat kick and without breathing in the middle of the distance, where the underwater stroke was recorded. The underwater motion of the right hand was recorded using four camcorders (60 Hz), which were positioned behind four stationary periscope systems. The synchronisation of the cameras was achieved using a LED system visible in the field of view of each camera. A calibration frame with dimensions of 1m x 3m x 1m for the transverse (X), the longitudinal (Y) and the vertical (Z) directions, respectively, containing 24 control points, was used for the calibration of the recorded space in the middle of the 25 m swimming pool (Gourgoulis et al., 2008a). Before filming, selected points were marked on each swimmer’s skin corresponding to the acromion of the right shoulder, the greater trochanter of the right and left hip, and four points on the right hand: the center of the wrist, the tip of the middle finger, the index and the little finger metacarpophalangeal joints. These points were digitized using the Ariel Performance Analysis System (Ariel Dynamics Inc., San Diego CA, USA) and their three dimensional coordinates were calculated using the direct linear transformation procedure. For a detailed description and quantification, the underwater stroke of the right hand was divided into three distinct phases: (a) entry and catch, (c) pull and (c) push (Chollet et al., 2000). The hydrodynamic coefficients and the methodology presented by Sanders (1999) were used for the estimation of the drag force, the lift force and the resultant force of the swimmer’s hand. Moreover, the component of the resultant force in the swimming direction, defined as the effective propulsive force generated from the swimmer’s hand, and the angle between the resultant force and the axis of propulsion were calculated (Gourgoulis et al., 2008c). The stroke length, the stroke rate and the mean swimming velocity were also calculated (Gourgoulis et al., 2008b). For the statistical treatment of the data, the t-test for dependent samples was used. The normal distribution and the homogeneity of variance were verified using the Kolmogorov – Smirnov test and the Levene test, respectively. The significance level was set as p < 0.05. results During resisted swimming the stroke length, the stroke rate and the mean swimming velocity were decreased significantly (Table 1). Table 1. Stroke length (m), stroke rate (cycles⋅s -1 ) and mean swimming velocity (m⋅ s -1 ) during front crawl swimming with and without added resistance. Without added resistance With added resistance t- value Stroke length 1.88 ± 0.07 1.28 ± 0.08 13.155* Stroke rate 0.84 ± 0.04 0.74 ± 0.06 5.188* Mean swimming velocity * p < 0.05 1.57 ± 0.09 0.95 ± 0.13 26.750* During the pull and the push phase, the magnitude of the mean drag force, the mean lift force, the mean resultant force and the mean effective propulsive force, were not altered significantly, in comparison with free swimming. On the other hand, the angle between the vector of the resultant force and the axis of swimming propulsion was decreased significantly during the pull phase in the resisted swimming condition. This modification was not observed during the push phase (Table 2). 89
BiomechanicsandmedicineinswimmingXi Table 2. Mean drag force (N), mean lift force (N), mean resultant force (N), mean effective force (N), and angle between the vector of the resultant force and the axis of swimming propulsion (deg) during front crawl swimming with and without added resistance. 90 Without added resistance With added resistance t- value Pull phase Drag force 9.20 ± 2.57 9.16 ± 2.46 0.028 Lift force 7.50 ± 2.45 5.76 ± 1.59 2.679 Resultant force 12.34 ± 2.59 11.21 ± 2.38 1.061 Effective force Angle between the vector of the resultant force and the axis of 9.47 ± 1.71 10.04 ± 2.12 0.532 swimming propulsion 36.31 ± 14.73 13.26 ± 15.37 2.877* Push phase Drag force 7.27 ± 2.40 8.76 ± 4.62 0.562 Lift force 12.59 ± 2.32 11.70 ± 4.52 0.630 Resultant force 14.93 ± 2.50 14.85 ± 6.28 0.033 Effective force Angle between the vector of the resultant force and the axis of 12.89 ± 2.06 13.19 ± 6.44 0.121 * p < 0.05 swimming propulsion -5.18 ± 16.76 -16.09 ± 9.56 1.462 dIscussIon The results showed that during resisted swimming the mean swimming velocity decreased significantly. This was expected, because both the stroke length, as well as the stroke rate decreased due to the increased resistance that should be overcame by the swimmers (Llop et al., 2006; Maglischo et al., 1985; Williams et al., 2001). During sprint-resisted swimming no significant modifications were observed in the magnitude of the drag and lift forces, in any of the propulsive phases of the underwater stroke. Consequently, it was not observed any significant modification in the magnitude of the resultant force and the effective force. However, the drag force seems to predominate more against lift force in the pull phase during resisted swimming, in comparison with free swimming. Although this fact was not statistically significant, it could be seen as a positive modification, as according to Rushall et al. (1994), Sanders (1998) and Maglischo (2003), it is more effective when swimmers rely more on drag, rather than on lift forces. Such combination of the drag and lift forces has as consequence to maximize their contribution to the forward direction and as much as possible of the resultant force to be aimed in the swimming direction. Optimally, the angle between the resultant force and the axis of swimming propulsion should be as close as possible to zero (Schleihauf, 2004; Vorontsov & Rumyantsev, 2000). In the present study, although the magnitude of the drag and the lift forces were not altered significantly, the angle formed between the resultant force and the axis of swimming propulsion was decreased significantly in the pull phase during resisted swimming, in comparison with free swimming. The mean value of the above mentioned angle was decreased from approximately 36 degrees during free swimming to 13 degrees during resisted swimming and thus the resultant force was steered more in the forward swimming direction. conclusIon The main findings of the present study indicate that although the magnitude of the drag and lift forces, as well as the magnitude of the resultant force and the effective propulsive force were not modified significantly during resisted swimming, in comparison with free swimming, the angle formed between the resultant force and the axis of the swimming propulsion was decreased significantly in the pull phase. Thus, it could be speculated that front crawl sprint-resisted swimming with the concrete added resistance could be considered a specific trainings form, which probably could contribute to the learning of a more effective application of the propulsive forces during the pull phase. reFerences Arellano R. (1999). Vortices and propulsion. In: Sanders R. & Linsten J. (eds.), Swimming: Applied Proceedings of the XVII International Symposium on Biomechanics in Sports (pp 53 – 66). Perth, Western Australia: School of Biomedical and Sports Science. Chollet D., Chalies S., Chatard J. C. (2000). A new index of coordination for the crawl: description and usefulness. Int J Sports Med, 21, 54 – 59. Girold S., Maurin D., Dugué B., Chatard J. C., Millet G. (2007). Effects of dry-land vs. resisted and assisted - sprint exercises on swimming sprint performances. J Strength Cond Res, 21 (2), 599 – 605. Gourgoulis V., Aggeloussis N., Kasimatis P., Vezos N., Boli A., Mavromatis G. (2008a). Reconstruction accuracy in underwater three dimensional kinematic analysis. J Sci Med Sport, 11, 90-95. Gourgoulis V., Aggeloussis N., Vezos N., Antoniou P., Mavromatis G. (2008b). Hand orientation in hand paddle swimming. Int J Sports Med, 29, 429 – 434. Gourgoulis V., Aggeloussis N., Vezos N., Kasimatis P., Antoniou P., Mavromatis G. (2008c). Estimation of hand forces and propelling efficiency during front crawl swimming with hand paddles. J Biomech, 41, 208 – 215. Llop F., Tella V., Colado J.C., Diaz G., Navarro F. (2006). Evolution of butterfly technique when resisted swimming with parachute, using different resistances. In: Vilas-Boas J. P., Alves F., Marques A. (eds.). Biomechanics and Medicine in swimming. Xth International Symposium (pp 302 – 304). Porto, Portugal. Maglischo C. W., Maglischo E. W., Sharp R. L., Zier D. J., Katz A. (1984). Tethered and nontethered crawl swimming. In: Terauds J., Barthels K., Kreighbaum E., Mann R., Crakes J. (eds.). Proceedings of ISBS: Sports Biomechanics (pp 163-176). Del Mar, C. A.: Academic Publication. Maglischo E. W., Maglischo C. W., Zier D. J., Santos T. R. (1985). The effect of sprint – assisted and sprint resisted swimming on stroke mechanics. J Swim Res, 1, 27-33. Maglischo E. W. (2003). Swimming fastest. Champaign, IL: Human Kinetics. Mavridis G., Kabitsis Ch., Gourgoulis V., Toubekis A. (2006). Swimming velocity improved by specific resistance training in age-group swimmers. In: Vilas-Boas J. P., Alves F., Marques A. (eds.). Biomechanics and Medicine in swimming. Xth International Symposium (pp 304 – 306). Porto, Portugal. Rushall B. S., Sprigings E. J., Holt L. E., Cappaert J. M. (1994). A Reevaluation of forces in swimming. J Swim Res, 10, 6 – 30. Sanders R. H. (1998). Lift performance in aquatic sports. In: Riehle H. J. & Vieten M. M. (eds). Proceedings XVI International Symposium of Biomechanics in Sports (pp 25 – 39). Germany: University of Konstanz. Sanders R. (1999). Hydrodynamic characteristics of a swimmer’s hand. J Appl Biomech, 15, 3 – 26. Schleihauf R. E. (2004). Biomechanics of Human Movement. Bloomington, Indiana: Authorhouse. Toussaint H. M., Hollander A. P., Berg Cvd., Vorontsov A. R. (2000). Biomechanics of swimming. In: Garrett W. E., Kirkendall D. T. (eds.). Exercise and Sport Science (pp 639-660). Philadelphia, Lippincott: Williams & Wilkins. Vorontsov A. R., Rumyantsev V. A. (2000). Propulsive forces in swimming. In: Zatsiorsky V. M. (ed.). Biomechanics in Sport – Performance, enhancement and injury prevention (pp 205-231). International Olympic Committee: Blackwell Science Ltd. Williams B. K., Sinclair P., Galloway M. (2001). The effect of resisted and assisted freestyle swimming on stroke mechanics. In: Blackwell J. R., Sanders R. H. (eds.). Proceedings of Swim Sessions. XIX International Symposium on Biomechanics in Sports (pp 131 – 134). San Francisco, USA.
Page 1 and 2:
Biomechanics and Medicine in Swimmi
Page 3 and 4:
Bibliographic information: Biomecha
Page 5 and 6:
Biomechanicsandmedicinein
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40: Biomechanicsandmedicinein
Page 81 and 82: Figure 1. General biomechanical par
Page 89: Biomechanicsandmedicinein
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
average VO2 measured during resting
Page 219 and 220:
Page 221 and 222:
Fourteen highly trained male swimme
Page 223 and 224:
Page 225 and 226:
Page 227 and 228:
Page 229 and 230:
Page 231 and 232:
Page 233 and 234:
Page 235 and 236:
Page 237 and 238:
Page 239 and 240:
Page 241 and 242:
Page 243 and 244:
Page 245 and 246:
Page 247 and 248:
Page 249 and 250:
Page 251 and 252:
Page 253 and 254:
Page 255 and 256:
Page 257 and 258:
Page 259 and 260:
Page 261 and 262:
Page 263 and 264:
Page 265 and 266:
Page 267 and 268:
Figure 2. Repeatability of the LTin
Page 269 and 270:
Page 271 and 272:
Page 273 and 274:
Page 275 and 276:
Page 277 and 278:
Page 279 and 280:
Page 281 and 282:
Page 283 and 284:
Page 285 and 286:
Page 287 and 288:
Page 289 and 290:
Page 291 and 292:
Page 293 and 294:
Page 295 and 296:
Page 297 and 298:
Page 299 and 300:
-ARM * 5 Biomechanicsandmedic
Page 301 and 302:
Page 303 and 304:
Page 305 and 306:
Page 307 and 308:
Page 309 and 310:
Page 311 and 312:
Page 313 and 314:
Page 315 and 316:
Page 317 and 318:
Page 319 and 320:
• Without restriction; • Blinde
Page 321 and 322:
Page 323 and 324:
Page 325 and 326:
Page 327 and 328:
Page 329 and 330:
Page 331 and 332:
Page 333 and 334:
Page 335 and 336:
Page 337 and 338:
Page 339 and 340:
Page 341 and 342:
Page 343 and 344:
Page 345 and 346:
Page 347 and 348:
Page 349 and 350:
Page 351 and 352:
Page 353 and 354:
Page 355 and 356:
Page 357 and 358:
Page 359 and 360:
etween experimental groups and cont
Page 361 and 362:
Page 363 and 364:
Page 365 and 366:
Page 367 and 368:
Page 369 and 370:
Page 371 and 372:
Page 373 and 374:
Page 375 and 376:
Page 377 and 378:
Page 379 and 380:
Page 381 and 382:
Page 383 and 384:
Page 385 and 386:
Page 387 and 388:
Page 389 and 390:
Page 391:
Pahlen Norge AS Pahlen Norge AS Cha
show all

Biomechanics and Medicine in Swimming XI

Create successful ePaper yourself

Delete template?

Save as template?