Effects of Intensified Military Field Training on Jumping Performance

Abstract

A sensitive, reliable, field-expedient test may be valuable for monitoring interventions during periods of anticipated physical performance decline. The purpose of this study was to determine the capabilities of unloaded jumping tests for detecting decrements in physical performance following eight days of military sustained operations. Twenty-nine U. S. Marines (24 ± 1 y; 180 ± 6 cm; 82.5 ± 8.2 kg) performed 1, 5 and 30 repetition(s) of unloaded countermovement jumps (UJ) before and after eight days of sustained operations (SUSOPS). Jump performance data was collected simultaneously using a switch mat (SM) and a linear position transducer (LPT). Jump height (m) and power (W) were highest using 1 UJ and declined 4.9 and 8.9 %, respectively after SUSOPS. Jump power (JP) declined progressively over 30 UJ (20 %). Five UJ offered no advantages over 1 UJ and was inadequate to examine changes in muscle fatigability (pre: 1294 ± 138 W; post: 1250 ± 165 W). The SM and a LPT were in agreement and had a high correlation (r = 0.92). One UJ was a sensitive, easy to implement test for monitoring the collective impact of high physical, nutritional, cognitive, and environmental stress on an individuals' physical performance before and after 8 days of SUSOPS, suggesting decrements in physical performance associated with overreaching can be detected by simply administered field-expedient jumping tests.

soldier - physical performance - energy restriction - military

References

• 1 Alemany J A, Pandorf C E, Montain S J, Castellani J W, Tuckow A P, Nindl B C. Reliability assessment of ballistic jump squat and bench throws.  J Strength Cond Res. 2005;  19 33-38
• 2 Bland J M, Atlman D G. Statistical methods for assessing agreement between methods of clinical measurement.  Lancet. 1986;  1 307-310
• 3 Bosco C, Thihnayi J, Komi P V, Fekete G, Apor P. Store and recoil of elastic energy in slow and fast types of human skeletal muscles.  Acta Physiol Scand. 1982;  116 343-349
• 4 Bosco C, Luhtanen P, Komi P V. A simple method for the measurement of mechanical power in jumping.  Eur J Appl. 1983;  50 273-282
• 5 Chicharro J L, Lopez-Mojares L M, Lucia A. Overtraining parameter in special military units.  Aviat Space Enviorn Med. 1998;  69 562-568
• 6 Cronin L B, Hing R D, McNair P J. Reliability and validity of a linear position transducer for measuring jump performance.  J Strength Cond Res. 2004;  18 2004
• 7 Delany J P, Schoeller D A, Hoyt R W, Askew E W, Sharp M A. Field use of D2 18O to measure energy expenditure of Soldiers at different energy intakes.  J Appl Physiol. 1989;  67 1922-1929
• 8 Dugan E L, Doyle T A, Humphries B, Hasson C J, Newton R U. Determining the optimal load for jump squats: a review of methods and calculation.  J Strength Cond Res. 2004;  18 668-674
• 9 Filarie E, Maso F, Degoutte F, Jouanel P, Lac G. Food restriction, performance, psychological state and lipid values in judo athletes.  Int J Sports Med. 1993;  22 454-459
• 10 Fogelholm G M, Koskinen R, Laasko J, Rankinen T, Ruokonen I. Gradual and rapid weight loss: effects on nutrition and performance in male athletes.  Med Sci Sports Exerc. 1993;  25 371-377
• 11 Friedl K E, DeLuca J P, Marchitelli L J, Vogel J A. Reliability of body fat estimates from a four-compartment model by using density, body water and bone mineral density.  Am J Clin Nutr. 1992;  55 764-770
• 12 Friedl K E, Moore R J, Martinez-Lopez L E. Lower limit of body fat in healthy active men.  J Appl Physiol. 1994;  77 933-940
• 13 Fry A C, Kraemer W J, van Borselen F BF. Performance decrements with high-intensity resistance exercise overtraining.  Med Sci Sports Exerc. 1994;  26 1165-1173
• 14 Harman E A, Rosenstein M, Frykman P N, Rosenstein R, Kraemer W J. Estimation of human power output from vertical jump.  J Appl Sports Sci Res. 1991;  5 116-120
• 15 Haslon S L, Jeukendrup A E. Does overtraining exist? An analysis of overreaching and overtraining research.  Sports Med. 2004;  34 967-981
• 16 Hoffman J R, Kang J. Evaluation of a new anaerobic power testing system.  J Strength Cond Res. 2002;  16 142-148
• 17 Hopkins W G. How to interpret changes in athletic performance test.  Sportscience. 2004;  8 1-7
• 18 Johnson M J, Friedl K E, Frykman P N, Moore R J. Loss of muscle mass is poorly reflected in grip strength performance in healthy young men.  Med Sci Sports Exerc. 1994;  26 235-240
• 19 Kreider R B, Fry A C, O'Toole M L. Overtraining in sport: terms, definitions and prevalence. Kreider RB, Fry AC, O'Toole ML Overtraining in Sports. Champaign, IL; Human Kinetics 1998: vii-xi
• 20 Legg S J, Haslam D R. Effect of sleep deprivation on self-selected workload.  Ergonomics. 1984;  27 389-396
• 21 Murphy M M, Patton J F, Frederick F A. Comparative anaerobic power of men and women.  Aviat Space Environ Med. 1986;  57 636-641
• 22 Nindl B C, Friedl K E, Frykman P N, Marchitelli L J, Shippee R L, Patton J F. Physical performance and metabolic recovery among lean, healthy men following a prolonged energy deficit.  Int J Sports Med. 1997;  18 317-324
• 23 Nindl B C, Leone C D, Tharion W J, Johnson R F, Castellani J W, Patton J F, Montain S J. Physical performance responses during 72 h of military operational stress.  Med Sci Sports Exerc. 2002;  34 1814-1822
• 24 Nindl B C, Kellogg M D, Khosravi M J, Diamandi A, Alemany J A, Pietila D M, Young A J, Montain S J. Measurement of insulin-like growth factor-I during military operational stress via a filter paper blood spot assay.  Diabetes Technol Ther. 2003;  5 455-461
• 25 Opstad P K. Androgenic hormones during prolonged physical stress, sleep, and energy deprivation.  J Clin Endocrinol Metab. 1992;  74 1176-1183
• 26 Patton J F, Murphy M M, Frederick F A. Maximal power outputs during the Wingate anaerobic test.  Int J Sports Med. 1985;  6 82-85
• 27 Viitasalo J T, Kyrolainen H, Bosco C, Alen M. Effects of rapid weight reduction on force production and vertical jumping height.  Int J Sports Med. 1987;  8 281-285