THE EFFECT OF SHORT-TERM OFF-SEASON CROSS-COUNTRY SKI TRAINING ON BODY COMPOSITION, PHYSICAL FITNESS, AND ISOKINETIC MUSCLE FUNCTIONS OF CROSS-COUNTRY SKIERS

Background and objective

The purpose of this study is to analyze the effects of short-term off-season training (competition) on body composition, physical fitness, and isokinetic muscle functions of XC skiers.

Material and Methods

Seven XC skiers, including two national team members and five reserve national team members, partici-pated in the study. Short-term off-season XC ski training was conducted for over 4 weeks (August–September). The physical composition, basic physical fitness, and isokinetic muscle function tests were conducted at S hospital in Seoul, South Korea before and after off-season ski training. The training pro-gram was conducted in New Zealand at S cross-country ski stadium (altitude 1350 m) in afternoons, and the ground training was conducted at Y area (altitude 300 m) in afternoons. The main training directions were polarized training and core stability. Weight training was not available because of local conditions.

Results

The short-term off-season XC ski training showed no differences (p>0.05) in body composition, such as weight, muscle mass, and body fat. There were significant differences (p<0.001) in the chest size and bra-chial muscle but no significant differences (p>0.05) in the antebrachial, femoral, and crural muscles. Basic physical fitness tests showed no significant differences (p>0.05) in strength, flexibility, agility, and balance. However, the power ratio between the right and left grip strength showed significant difference (p<0.05).

Peak torque of isokinetic muscle function of knee joints was measured at 60°/s.There were no significant differences (p>0.05) in both knee extensions before and after training, but, in contrast, there were significant differences (right knee, p<0.01 and left knee, p<0.05) in flexions. The ratio of the right knee flexion and extension muscle was significantly different between before and after training measurements (p<0.05). The ratio of the left and right knee flexion and extension muscle was signifi-cantly different (p<0.05) between before and after training measurements. While comparing the right and left knees, the ratio of the knee extension and flexion was not significantly different (p>0.05) between before and after training measurements.

Conclusion

Short-term off-season XC ski training (competition) of 4 weeks increased XC skiers’ cross-section area of the chest and brachial muscle. It also improved the isokinetic muscle function of knee joints and the power of lower body.

Our research is expected to provide basic information for XC skiers who plan ski training and compe-tition during summer training period. However, further studies on the differences between roller- skating and ski training conducted during summers are needed.

off-season cross-country ski training; body composition; physical fitness; isokinetic muscle strength; polarized training; core stability training

1. Mahood NV, Kenefick RW, Kertzer R, Quinn TJ. Physiological determinants of cross-country ski racing performance. Med Sci Sports Exerc 2001;33(8):1379–84. https://doi.org/10.1097/ 00005768-200108000-00020

2. Sandbakk Ø, Holmberg H-C. A reappraisal of success factors for Olympic cross-country skiing. Int J Sports Physiol Perform 2014;9(1):117–21. https://doi.org/10.1249/MSS.0000000000000862

3. Stoeggl TL, Holmberg H-C. Double-poling biomechanics of elite cross-country skiers: Flat versus uphill terrain. Med Sci Sports Exerc 2016;48(8):1580–9. https://doi.org/10.1519/00124278-200008000-00007

4. Alsobrook NG, Heil DP. Upper body power as a determinant of classical cross-country ski perfor-mance. Eur J Appl Physiol 2009;105(4):633–41. https://doi.org/10.1007/s00421-008-0943-z

5. Losnegard T, Mikkelsen K, Rønnestad BR, Hallén J, Rud B, Raastad T. The effect of heavy strength training on muscle mass and physical performance in elite cross country skiers. Scand J Med Sci Sports 2011;21(3):389–401. https://doi. org/10.1111/j.1600-0838.2009.01074.x

 6. Sandbakk Ø, Hegge AM, Losnegard T, Skattebo Ø, Tønnessen E, Holmberg H-C. The physiological capacity of the world’s highest ranked female cross-country skiers. Med Sci Sports Exerc 2016;48(6):1091. https://doi.org/ 10.1249/ MSS.0000000000000862

7. Holmberg H-C, Lindinger S, Stöggl T, Eitzlmair E, Müller E. Biomechanical analysis of double poling in elite cross-country skiers. Off J Am CollSports Med 2005;37(5):807–18. https://doi. org/ 10.1249/01.MSS.0000162615.47763.C8

8. Losnegard T, Hallén J. Elite cross-country skiers do not reach their running VO2max during roller ski skating. J Sports Med Phys Fitness 2014;54(4): 389–93.

9. Hoffman MD, Clifford PS. Physiological aspects of competitive cross-country skiing. J Sports Sci 1992;10(1):3–27. https://doi.org/10.1080/0264041 9208729903

 10. Millet GP, Boissiere D, Candau R. Energy cost of different skating techniques in cross-country skiing. J Sports Sci 2003;21(1):3–11. https://doi. org/10.1080/0264041031000070903

 11. Millet GY, Hoffman MD, Candau RB, Clifford PS. Poling forces during roller skiing: Effects of grade. Med Sci Sports Exerc 1998;30(11):1637–44. https://doi.org/10.1097/00005768-199811000- 00013

 12. Ronsen O, Rusko H. Special and practical issues in cross country skiing. Handbook of sports medicine and science: Cross Country Skiing. Germany Blackwell Science 2003; 141–75. https://doi.org/10.1002/9780470693834.ch5F

 13. http://www.fis-ski.com/FISF.

 14. Brugniaux JV, Schmitt L, Robach P, et al. Eighteen days of “living high, training low” stimulate erythropoiesis and enhance aerobic performance in elite middle-distance runners. J Appl Physiol 2006;100(1):203–11. https://doi.org/10.1152/jap-plphysiol. 00808.2005

 15. Cuzzolin FSL, Rossi L, Pasetto M, Benoni G. Plasma nitrite/nitrate and erythropoietin levels in cross-country skiers during altitude training. J Sports Med Phys Fitness 2002;42(2):129.

 16. Ingjer F, Myhre K. Physiological effects of altitude training on elite male cross-country skiers. J Sports Sci 1992;10(1):37–47. https://doi. org/ 10.1080/02640419208729905

 17. Robach P, Schmitt L, Brugniaux JV, et al. Living high–training low: Effect on erythropoiesis and maximal aerobic performance in elite Nordic skiers. Eur J Appl Physiol 2006;97(6):695–705. https://doi.org/10.1007/s00421-006-0240-7

 18. Wehrlin JP, Zuest P, Hallén J, Marti B. Live high-train low for 24 days increases hemoglobin mass and red cell volume in elite endurance athletes. J Appl Physiol 2006;100(6):1938–45. https://doi. org/10.1152/japplphysiol.01284.2005

 19. Bailey DM, Davies B. Physiological implications of altitude training for endurance performance at sea level: A review. Br J Sports Med 1997;31(3): 183–90. https://doi.org/10.1136/bjsm.31.3.183

 20. Tiollier E, Schmitt L, Burnat P, et al. Living high–training low altitude training: Effects on mucosal immunity. Eur J Appl Physiol 2005;94(3):298–304. https://doi.org/10.1007/s00421-005-1317-4

 21. Wolski LA, McKenzie D, Wenger H. Altitude training for improvements in sea level perfor-mance. Sports Med 1996;22(4):251–63. https://doi.org/10.2165/00007256-199622040-00004

 22. Čepulėnas A. Training loads cross-country skiers during skiing practice on snow in summer and autumn mesocycles. Science Nordic Skiing. Meyer & Meyer Verlag; 2007. 69–80.

 23. Fudge BW, Pringle JS, Maxwell NS, Turner G, Ingham SA, Jones AM. Altitude training for elite endurance performance: A 2012 update. Curr Sports Med Rep 2012;11(3):148–54. https://doi. org/10.1249/JSR.0b013e31825640d5

 24. Sandbakk Ø, Holmberg H-C. Physiological capac-ity and training routines of elite cross-country skiers: Approaching the upper limits of human endurance. Int J Sports Physiol Perform 2017;12(8): 1003–11. https://doi.org/10.1123/ijspp.2016-0749

 25. Videman T, Lereim I, Hemmingsson P, et al. Changes in hemoglobin values in elite cross-country skiers from 1987 to 1999. Scand J Med Sci Sports 2000;10(2):98–102. https://doi.org/ 10.1034/j.1600-0838.2000.010002098.x

 26. Rønnestad BR, Hansen J, Thyli V, Bakken TA, Sandbakk Ø. 5-week block periodization increases aerobic power in elite cross-country skiers. Scand J Med Sci Sports 2016;26(2):140–6. https://doi. org/10.1111/sms.12418

 27. Stöggl T, Sperlich B. Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training. Front Physiol 2014;5:33. https://doi.org/10.3389/fphys.2014.00033

 28. Marshall PW, Murphy BA. Core stability exercises on and off a Swiss ball. Arch Phys Med Rehabil 2005;86(2):242–9. https://doi.org/10.1016/j.apmr. 2004.05.004

 29. ACSM. American college sports medicine, ACSM’s guidelines for exercise testing and pre-scription. 9th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013.

 30. Klavora P. Vertical-jump tests: A critical review. Strength Condit J 2000;22(5):70–5. https://doi. org/10.1519/00126548-200010000-00020

 31. Sporis G, Vucetic V, Jovanovic M, Jukic I, Omrcen 

D. Reliability and factorial validity of flexibility tests for team sports. J Strength Condit Res 2011;25(4):1168–76. https://doi.org/10.1519/JSC. 0b013e3181cc2334

 32. Choi J, Park H, Lee W, Hong K. Effects of 3D compression pants and kinesio taping on isoki-netic muscular function of leg during knee joint flexion motion. J Korean Soc Cloth Text (JKSCT) 2016;40(2):240–57. https://doi.org/10.5850/JKSCT. 2016.40.2.240

 33. Choi YC. The effect of 3 weeks high altitude skiing training on isokinetic muscle function of cross-country skierst. J Korea Convergence Soc 2018;9(11):465–77.

 34. Bergh U, Forsberg A. Influence of body mass on cross-country ski racing performance. Med Sci Sports Exerc 1992;24(9):1033–9. https://doi.org/ 10.1249/00005768-199209000-00013

 35. Lippl FJ, Neubauer S, Schipfer S, et al. Hypobaric hypoxia causes body weight reduction in obese subjects. Obes Soc 2010;18(4):675–81. https://doi. org/10.1038/oby.2009.509

 36. Stöggl T, Enqvist J, Müller E, Holmberg H-C. Relationships between body composition, body dimensions, and peak speed in cross-country sprint skiing. J Sports Sci 2010;28(2): 161–9. https://doi.org/10.1080/02640410903 414160

 37. Terzis G, Stattin B, Holmberg HC. Upper body training and the triceps brachii muscle of elite cross country skiers. Scand J Med Sci Sports 2006;16(2):121–6. https://doi.org/10.1111/ j.1600-0838.2005.00463.x

 38. Gaskill SE, Serfass RC, Bacharach DW, Kelly JM. Responses to training in cross-country skiers. Med Sci Sports Exerc 1999;31:1211–17. https://doi.org/10.1097/00005768-199908000-00020

 39. Mikkola J, Laaksonen M, Holmberg H-C, Vesterinen V, Nummela A. Determinants of a simulated cross-country skiing sprint competition using V2 skating technique on roller skis. Sports Biomech 2010;24(4):920–8. https://doi.org/10.1519/JSC.0b013e3181cbaaaf

 40. Staib JL, Im J, Caldwell Z, Rundell KW. Cross-country ski racing performance predicted by aerobic and anaerobic double poling power. J Strength Condit Res 2000;14(3):282–8. https://doi.org/10.1519/00124278-200008000-00007

 41. Stoggl T, Muller E, Lindinger SJr. A specific upper body testing and training device and con- cept for strength capacities in cross-country ski racing. Science and skiing. Oxford: Meyer and meyer Sport; 2005. p. 326–39.

 42. Stöggl T, Mueller E, Ainegren M, Holmberg HC. General strength and kinetics: Fundamental to sprinting faster in cross country skiing? Scand J Med Sci Sports 2011;21(6):791–803. https://doi. org/10.1111/j.1600-0838.2009.01078.x

 43. Hae-Chan Park, Sun-Hee Park. Correlation on body composition and muscle strength of strength training during 8 weeks. J Korean Data Anal Soc 2014;16(5):2651–60.

 44. Koh YJ, Man Gyoon Lee, Sung Ah Kong. Comparison of body composition, physical fitness, and isokinetic Leg strength according to competition level in collegiate and high school taekwondo players. Exerc Sci 2007;16(4): 411–20. https://doi.org/10.15857/ksep.2007. 16.4.411

 45. Rønnestad BR, Hansen EA, Raastad T. Effect of heavy strength training on thigh muscle cross-sectional area, performance determinants, and performance in well-trained cyclists. Eur J Appl Physiol 2010;108(5):965–75. https://doi.org/ 10.1007/ s00421-009-1307-z

 46 Børve J, Jevne SN, Rud B, Losnegard T. Upper-body muscular endurance training improves per-formance following 50 min of double poling in well-trained cross-country skiers. Front Physiol 2017;8:690. https://doi.org/10.3389/fphys.2017. 00690

 47. Skattebo Ø, Hallén J, Rønnestad BR, Losnegard

T. Upper body heavy strength training does not affect performance in junior female cross-country skiers. Scand J Med Sci Sports 2016;26(9):1007–16. https://doi.org/10.1111/sms.12517

 48. Rindal O, Seeberg T, Tjønnås J, Haugnes P, Sandbakk Ø. Automatic classification of sub-techniques in classical cross-country skiing using a machine learning algorithm on micro-sensor data. Sensors 2018;18(1):75. https://doi.org/10.3390/s18010075

 49. Sakurai Y, Fujita Z, Ishige Y. Automatic identifi-cation of subtechniques in skating-style roller ski-ing using inertial sensors. Sensors 2016;16(4):473. https://doi.org/10.3390/s16040473

 50. Stöggl T, Holst A, Jonasson A, et al. Automatic classification of the sub-techniques (gears) used in cross-country ski skating employing a mobile phone. Sensors 2014;14(11):20589–601. https://doi.org/10.3390/s141120589

 51. Krenn O, Werner I, Lawrence E, Valero-Cuevas FJ. The lower extremity dexterity test quantifies sensorimotor control for cross-country skiing. Science and Skiing VI. Meyer & Meyer Verlag; 2015. p. 439–45.

 52. Lindinger SJ, Stöggl T, Müller E, Holmberg H-CJ. Control of speed during the double poling tech-nique performed by elite cross-country skiers. Med Sci Sports Exerc Sci 2009;41(1):210–20. https://doi.org/10.1249/MSS.0b013e318184f436

 53. Ronsen O, Rusko H. Biomechanics of cross coun-try skiing. Handbook of Sports Medicine Science: Cross Country Skiing. Germany Blackwell Science; 2003. p. 32–61.

 54. Carlsson M, Carlsson T, Hammarström D, Tiivel T, Malm C, Tonkonogi M. Validation of physio-logical tests in relation to competitive perfor-mances in elite male distance cross-country skiing. J Strength Condit Res 2012;26(6):1496–504. https://doi.org/10.1519/JSC.0b013e318231a799

 55. Hedelin R, Wiklund U, Bjerle P, Henriksson-Larsén KJ. Pre- and post-season heart rate variability in adolescent cross-country skiers. Scand J Med Sci Sports 2000;10(5):298–303. https://doi.org/10.1034/j.1600-0838.2000. 010005298.x