COORDINATION MOTOR SKILLS OF MILITARY PILOTS SUBJECTED TO SURVIVAL TRAINING ANDRZEJ TOMCZAK1,2 1
General Staff of the Polish Armed Forces, Department of Physical Education and Sport, Warsaw, Poland; and 2University of Physical Education in Warsaw, Biala Podlaska, Poland ABSTRACT
Tomczak, A. Coordination motor skills of military pilots subjected to survival training. J Strength Cond Res 29(9): 2460– 2464, 2015—Survival training of military pilots in the Polish Army gains significance because polish pilots have taken part in more and more military missions. Prolonged exercise of moderate intensity with restricted sleep or sleep deprivation is known to deteriorate performance. The aim of the study was thus to determine the effects of a strenuous 36-hour exercise with restricted sleep on selected motor coordination and psychomotor indices. Thirteen military pilots aged 30–56 years were examined twice: pretraining and posttraining. The following tests were applied: running motor adjustment (15-m sprint, 3 3 5-m shuttle run, 15-m slalom, and 15-m squat), divided attention, dynamic body balance, handgrip strength differentiation. Survival training resulted in significant decreases in maximum handgrip strength (from 672 to 630 N), corrected 50% max handgrip (from 427 to 367 N), error 50% max (from 26 to 17%), 15-m sprint (from 5.01 to 4.64 m$s21), and 15-m squat (2.20 to 1.98 m$s21). The training improvements took place in divided attention test (from 48.2 to 57.2%). The survival training applied to pilots only moderately affected some of their motor adjustment skills, the divided attention, and dynamic body balance remaining unaffected or even improved. Further studies aimed at designing a set of tests for coordination motor skills and of soldiers’ capacity to fight for survival under conditions of isolation are needed.
KEY WORDS prolonged exercise, survival of soldiers, sleep deprivation, motor adjustment, running motor adjustment
INTRODUCTION
R
escuing soldiers lost in combats, and especially military pilots, has been one of prime military duties. Apart from immediate effects, i.e., bringing the rescued back to shape so as to engage
Address correspondence to Andrzej Tomczak, [email protected]. 29(9)/2460–2464 Journal of Strength and Conditioning Research Ó 2015 National Strength and Conditioning Association
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him/her again in military actions, rescuing greatly improves the morale of the unit. Such actions are sometimes publicized by mass media, e.g., the rescue of Capt. Scott O’Grady shot down in 1995 in Bosnia. Military survival training in the Polish Army has received special attention in recent years because of increased awareness that it is highly probable that Polish soldiers will need survival skills on military missions (20). In the Polish Air Forces, survival training lasting several days was organized by the Military Training and Physical Fitness Center for pilots. The training consists of theoretical and practical classes, as well as a final, 36-hour continuous field exercise. The last part of the training is especially onerous for military pilots given the necessity to act on the ground and in hostile surroundings. The pilots are evaluated by instructors throughout the training. The psychological, physiological, and fitness evaluation of the trainees is essential for comprehensive optimization of training curricula, and extensive research was conducted in that area (6,12,14), especially in prolonged survival training (4,9,10,17). Assessments of psycho-emotional effects were conducted for diverse activities at survival exercises consisting of simulated prison of war and close questioning (16). Other assessments pertained to prolonged exertions and sleep deprivation (1,4,15). After the Korean war in the fifties, SERE (Survival, Evasion, Resistance, Escape) trainings, closely imitating possible actions and behavior of the enemy, were initiated (5). Taylor et al. (19) assessed the capacity of soldiers subjected to psychological skill training (PST), including a selected combination of goal setting, arousal/ attention control, positive self-talk, and mental imagery, to cope with a simulated enemy and resistance to the various forms of simulated exploitation in stressful mock-captivityrelated training challenges. Some observable effects of the PST intervention were noted but future research in that area is needed. In another study on SERE that included being in a mock prisoner of war camp, the soldiers were assessed with respect to the accuracy of eyewitness’ memory (16). During prolonged military operations, it is vital that reaction times to simple and complex visual stimuli be as short as possible. Furthermore, visual-motor coordination and performance of attention tasks should also be maintained at a high level. In previous studies on the effects of
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survival instructors during winter survival training (20). Another TABLE 1. Mean values (6SD) of handgrip strength variables in male military pilots related factor is the differentia(n = 13) participating in survival training.* tion of hand strength after a proVariable Pretraining Posttraining z longed physical exercise. During a 36-hour survival exercise for Max 672 6 268 630 6 249† 20.15z young men, a decrease of the 50% max 427 6 187 367 6 147† strength correction factor to Corrected 50% max 371 6 168 324 6 147† Error 50% max (%) 26 6 15 17 6 10 20.42z 50% of maximum strength was Error corr. (%) 11 6 9§ 7 6 5§ noted, the maximum strength PI max 0.905 6 0.045 0.905 6 0.051 0.00 remaining unchanged (4). HowPI 50% 0.798 6 0.091k 0.832 6 0.088k 0.36 ever, during a 5-day field trainPI corr. 0.853 6 0.083 0.831 6 0.044k 20.27 ing, a decrease in maximum *PI = performance index; z = standardized variable (day 2 vs. day 1). strength was reported while the †Significantly different from day 1: p # 0.05. maximum leg strength remained zp # 0.05. §Significantly (p , 0.01) different from error 50% max. unchanged (9). kSignificantly (p , 0.01) different from PImax. Despite extensive studies on the effects of different conditions of military service on psychophysical performance, a moderate-intensity survival training lasting 36 hours, no no reports on military pilots subjected to prolonged survival deterioration of visual coordination (17) or of multipletraining were found in the available literature. Thus, the aim choice reaction time (MCRT) (14) were noticed. However, of this study was to determine the selected coordination the highest levels of MCRT were found at about 70–80% of motor skills of military pilots subjected to long-lasting V_ O2max in graded exercise tests to exhaustion (23). survival training. Reports on the effects of prolonged survival training on the METHODS sense of balance are scarce. Posturographic analysis (7,14) and rotation tests (4,21) were conducted after overnight training, Experimental Approach to the Problem and both static and dynamic balance ability were found to To assess the impact long-lasting survival training has on the decline. Other authors also reported negative effects of sleep selected coordination motor skills; military pilots were deprivation (without physical load) on the state of balance. subjected for this study. Subjects were military pilots with Disorders in balance were also reported when testing was many years of military service. Before all testing, subjects undertaken in the early morning hours (2,13). were required to be rested and abstain from strenuous exercise for at least 24 hours. In the morning, before the Motor coordination, agility, and speed are factors that start of training, prestudy measurements were performed, determine the efficacy in close combat. Motor adjustment tests, that include those factors, were applied to candidates for and later began the 36-hour survival training. Immediately after completion of the training were conducted poststudy measurements. During the test set handgrip strength, divided TABLE 2. Mean (6SD) and standardized (z) values of motor coordination attention, motor adjustment variables in male military pilots (n = 13) participating in survival training.* skills, dynamic body balance. Variable Pretraining z Posttraining z The degree of changes was estimated. 15-m Sprint (SS) 5.01 6 0.43 0.08 4.64 6 0.51† 21.10z 3 3 5-m Shuttle run (SR) 15-m Slalom (SL) 15-m Squat (SQ) Divided attention [%] Rotational test [%]
3.15 2.85 2.20 48.2 67.9
6 6 6 6 6
0.24 0.29 0.60 16.5 17.3
0.39 21.96§ 21.68§
3.03 2.84 1.98 57.5 61.5
6 6 6 6 6
*SS = straight sprint; SR = shuttle run; SL = slalom; SQ = squat. †Significantly different from Day 1: p , 0.001. zp # 0.05. §p , 0.001. kSignificantly different from Day 1: p , 0.01. ¶Significantly different from Day 1: p # 0.05.
0.31 0.27 0.46k 23.4¶ 19.3
0.94§ 20.84z 22.09§
Subjects
Thirteen military pilots aged 36.3 6 8.3 years and being in service for 17.3 6 8.8 years, volunteered to take part in the study. Their mean body height was 181 6 5.6 cm, mean body weight was 83.4 6 6.7 kg, and BMI 25.6 6 2.2 kg$m22. The subjects provided their written
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Coordination Motor Skills of Military Pilots
TABLE 3. Mean values (6SD) of speed-strength (W1) and speed-agility (W2) indices in male military pilots (n = 13) participating in survival training. Index W1 W2
Pretraining
Posttraining
20.80 6 1.04* 20.79 6 0.81§
21.59 6 1.09†z 0.05 6 0.86k¶
*Significantly different from zero: p # 0.05. †Significantly different from zero: p , 0.001. zSignificantly different from the pre-training value: p , 0.001. §Significantly different from zero: p , 0.01. kSignificantly different from the pre-training value: p , 0.01. ¶Significantly (p , 0.01) different from W1.
consents, and the study was approved by the Ethics Committee of the Medical University in Warsaw. Procedure
The training consisted of the following tasks: mountain walking for a few hours with elements of climbing (abseiling rope, making knots), transport of a wounded companion on stretcher, constructing shelters, lighting fire, a night march on azimuth, orienteering and crossing a rope bridge; the total distance covered amounting to 22–24 km. The study consisted of a 36-hour continuous survival training conducted in a submontane area in winter. The temperatures ranged from 248C during the day to 2108C at night; there was no snowfall or strong wind. The pilots carried rucksacks containing basic military equipment weighing 10–12 kg throughout the training. The subjects received a supply of dry provisions and had unlimited access to drinking water. They slept for 2-3 hours in self-built shelters. The estimated total energy expenditure amounted to about 8600 kcal per subject. The tests were applied on the day before training (pretraining) and then after 36 hours, i.e., directly at the end of training (posttraining). All measurements were conducted under identical conditions in sports hall. The following measurements were conducted: 1. Handgrip strength 2. Divided attention 3. Motor adjustment skills (22) 4. Dynamic body balance (8). Handgrip Strength. Handgrip strength (in N) was determined with the use of PZA/3359 dynamometer (Fabrication Enterprises Inc., Elmsford, NY, USA) held in the preferred hand, in standing posture, arms along the trunk. Three tasks were performed to measure the force differentiation skill— maximum strength, an attempt at performing 50% of the maximum, and then a corrective attempt at performing the requested 50%. Every task was repeated 5 times and averaged. The results were presented as maximum force and as relative differences between the actual outcome and the re-
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quested 50% value (50% max and correction errors). In addition, from the 5 repetitions of maximum handgrip, the performance index (PI) was computed (18). This reflected the capacity to maintain the peak force in all 5 repetitions.
Divided Attention. Two types of signals were displayed on the screen: the first type contained shapes (a square, a circle, or a cross) placed in the central part of the monitor. When they were displayed in the above sequence, the “+” key was to be pressed with the right thumb (or the “Q” key with the left thumb). All other sequences were incorrect. The second type of signals consisted of small squares displayed in the various corners of the monitor. If 4 squares were displayed simultaneously in one of the corners, the “–” key was to be pressed with the right index finger (or the “l” key with the left index finger). After the test was completed, the numbers of correct attempts were displayed in the central part of the monitor, and the numbers of errors (omitted signals and incorrectly pressed keys) and percent ratios in the corners. The percent ratio of correct reactions to the sum of correct and erroneous ones was the test result. Motor Adjustment. The running tests were as follows: 15-m straight sprint (SS), shuttle run 3 3 5-m (SR; standing start), 15-m slalom run (SL; first pole at a 5-m distance from the start, the remaining 4 spaced by 1.2 m; standing start), and 15-m squat (SQ, crouching start). Running times were recorded electronically with 0.01-second accuracy; the results were presented as velocities (15 / time) and as standardized values. From those standardized values, the speed-strength (W1) and speed-agility (W2) indices were computed: W1 = (zSS + zSQ) / 2, W2 = (zSR + zSL) / 2 (18). Dynamic Body Balance. A rotation test was applied; a subject stood on the line and attempted to perform a jump with full rotation (alternately clockwise and counterclockwise, repeated 3 times) and landed with both feet on the line in ;12 seconds at a constant rhythm; 6 training jumps being allowed. The accuracy of landing and maintaining the balance was scored (0 – clean jump, 1 – 1 foot off the line, 2 – both feet off the line, 3 – lost balance with hand support) and summarized from 6 jumps (score range from 0 – excellent to 18 – unsatisfactory). Statistical Analyses
Kolmogorow-Smirnow’s test was used to check the normality of distributions. The velocities were standardized using the following equations (22):
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Journal of Strength and Conditioning Research zSS ¼ ðSS24:98Þ=0:31 zSQ ¼ ðSQ23:09Þ 0:53 zSR ¼ ðSR20:616$SSÞ=0:18 zSL ¼ ðSL20:651$SSÞ=0:21: The between-day differences in mean values were assessed using Student’s t test for dependent measures. Statistica 6.0 software was used in data analysis, the level of p # 0.05 being considered significant.
RESULTS The results are presented in Tables 1–3. Maximum handgrip strength significantly decreased posttraining (by ;6%; t = 2.23, p , 0.046). Mean percent errors of correcting the requested attempts at 50% of the maximum handgrip (error corr.) were markedly lower (8 6 12 vs. 26 6 15 and 1 6 9 vs. 17 6 11, preand post-training, respectively) than those of the first attempt (error 50% max). Moreover, both errors were markedly lower posttraining than pretraining (17 6 11 vs. 26 6 15 and 1 6 9 vs. 8 6 12, respectively; see Table 1). The PI, a measure of task precision, did not significantly change posttraining. The applied survival training resulted in significant decreases in the SS and SQ runs (by 7%, p , 0.001, and by 10%, p , 0.01, respectively) and in a significant improvement (by 19%, p # 0.05) in the divided attention test. No significant differences were found for SR and SL runs or for the rotational test results. However, standardized (vs. reference values used in equations) velocities of SR and SL runs revealed a marked posttraining improvement in the SR run (Table 2). When the standardized results of running tests were converted to W1 and W2 indices, the speed-strength index (W1) that was lower from the reference value pretraining (p # 0.05) decreased further posttraining (p , 0.001). However, the speed-agility index (W2) that was also lower from the reference value pretraining (p , 0.01) significantly improved posttraining (p , 0.01) and attained the reference level (z = 0.05; Table 3). No significant correlations of the variables studied with BMI values were found either pre- or post-training.
DISCUSSION Coordination skills and psychomotor performance are of utmost importance for military pilots. In addition, highperformance aircraft pilots should be prepared for acceleration tolerance and, for that reason, particular emphasis is placed on strength training and special gymnastics L1, i.e., shaping the anaerobic potential. However, military pilots ought to be prepared to carry out SERE-related tasks including the survival training. It specifically involves prolonged stays under extreme conditions, e.g., after being shot down or after an emergency landing in an enemy area, going long distances on foot, etc. (17,21).
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A high performance of military tasks related to psychomotor agility, attention focusing, reaction time, perception, and visual-motor coordination, depends on factors such as age, work experience, vigilance, and mood (12,17,18). It was demonstrated (14,18) that a prolonged application of exercise combined with sleep deprivation did not affect the psychomotor performance of civilians. In this study, military pilots attained better results of the divided attention test immediately post- than pre-training, and the same was true for the handgrip force differentiation skill. This was probably due to pilots’ experience in performing under diverse conditions of weather, training, and military actions. The pilots had to make use of all skills assessed by the applied tests, and their attention focusing was more intense than in performing daily activities; working under the pressure of time and of the unpredictability of events, they did their best to accomplish every task as if they fought for life. In that way they achieved skills necessary in dangerous circumstances. The obtained results seem to comply with the first law of Yerkes-Dodson, according to which the relation between the task performance and emotional stimulation is nonlinear, i.e., both too low or too high stimuli impair the performance. In other words, the loads the pilots were subjected to were fully tolerable. The psychomotor skills desired when functioning in isolation include differentiation of hand strength that can be useful when performing injection, operating mobile radio station, using weapon, etc. Another factor important in military actions is the recovery rate after upper extremity exertions. Leyk et al. (11) reported that subjects who, under laboratory conditions, executed a task consisting of carrying a load of 50 kg over a distance of about 264 m in about 215 seconds experienced fatigue of upper extremities and a decrease of maximum strength that persisted over the next day. However, hand steadiness returned back to normal 30 minutes postexertion. Such a situation may happen in real actions, e.g., in emergency landing on enemy’s territory when one of the pilots gets injured. When the activities performed under difficult conditions persist, the performance deteriorates. In this study, the activities lasted 36 hours and no deterioration of psychomotor performance was noted. However, when survival training lasted as long as 53 or 73 hours and was combined with sleep deprivation, marked decreases in psychomotor tests and in the Profile of Mood States were observed (12). Commanding officers have to know how long it takes a soldier to start losing his/her psychomotor and work capacity and what is his/her general state. That knowledge would enable assessing soldier’s capacity to function in a rescue action. Motor adjustment tests applied in this study are informative with respect to the motor potential at short distances; good results of those tests are indicative of a high fitness in sudden changes of the running course, in crawling, in secretive approaches, etc. Mastering such behaviors is necessary in close-range combats, in settled areas, etc. Most test results attained by pilots in this study were negatively affected by the survival training, the 15-m VOLUME 29 | NUMBER 9 | SEPTEMBER 2015 |
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Coordination Motor Skills of Military Pilots SQ being an exception. In contrast, physical education students who underwent comparable loads exhibited decreased posttraining results only in the 15-m sprint, other runs remaining unaffected (20). The pilots were, however, by 14 years (on average) older than students, and the speed-agility skills are known to be age-dependent. In case of dynamic equilibrium, no significant differences between the pre- and post-training results were noted in pilots, whereas in physical education students the training load negatively affected their capacity to maintain balance (4). Huang et al. (7) reported that in civilians, subjected to carrying military equipment and thus fatigued, the mediolateral sway and the resulting postural sway were increased and that could enhance the risk of injury. Such disorders could impair safe functioning of pilots, e.g., readiness to undertake forced march, to leap away from the landing spot, to move at close range in a fight, etc., but the pilots in this study proved sufficiently well-trained.
PRACTICAL APPLICATIONS The subject discussed in this article is fairly novel; the presented data gave an insight into the effects of prolonged exercise combined with restricted sleep applied to military pilots on their performance in several psychomotor tests. It seems that to provide effective execution of precise tasks during military action coordination and strength endurance trainings should be introduced in soldiers’ drills. However, the reports on that subject are very scarce, and this calls for undertaking further studies aimed at designing a set of tests for coordination motor skills and of soldiers’ capacity to fight for survival under conditions of isolation.
ACKNOWLEDGMENTS The author thanks military pilots for their committed participation in the study and to Prof. R. Stupnicki for his expert statistical advice.
REFERENCES 1. Alhola, P and Polo-Kantola, P. Sleep deprivation: Impact on cognitive performance. Nuropsychiastr Dis Treat 3: 553–567, 2007. 2. Avni, N, Avni, I, and Barenboim, E. Brief posturografic test as an indicator of fatigue. Psychiatry Clin Neurosci 60: 340–346, 2006. 3. Blatter, K, Graw, P, Munch, M, Knoblauch, V, Wirz-Justice, A, and Cajochen, C. Gender and age differences in psychomotor vigilance performance under differential sleep pressure conditions. Behav Brain Res 168: 312–317, 2006. 4. Da˛browski, J, Ziemba, A, Tomczak, A, and Mikulski, T. Physical performance of healthy men exposed to long exercise and sleep deprivation. Med Sport 16: 6–11, 2012. 5. Doran, A, Hoyt, G, and Morgan, ChA III. Survival, Eviation, Resistance and Escape (SERE) training: Preparing military members for the demands of capacity. In: CH Kennedy and EA Zillmer, eds. Military Psychology: Clinical and Operational Applications. New York, NY: Guildford Publications, 2006. p. 241–261. 6. Hoyot, RW, Opstad, PK, and Haugen, AH. Negative energy balance in male and female rangers: Effects of 7 days of sustained exercise and food deprivation. Am J Clin Nutr 83: 1068–1075, 2006.
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7. Huang, G, Lovalekar, M, Abt, J, Sell, T, and Lephart, S. Interaction of military load carriage and fatigue on postural sway in young healthy subjects. In: K Hakkinen, H Kyro¨la¨inen, and R Taipale, eds. Proceedings of the Second International Congress on Soldiers’ Physical Performance, 2011 May 4–7. Jyva¨skyla¨, Finland: The Finnish Defense Forces, 2011. ´ 8. Kalina, RM, Jagiełło, W, and Barczynski, BJ. The method to evaluate the body balance disturbation tolerance skills—Validation procedure of the ‘Rotational test’. Arch Budo 9: 59–69, 2013. 9. Keina¨nen, L, Vaara, J, Kokko, J, and Kyro¨la¨inen, H. Neuromuscular performance, body composition and cardiac autonomic regulation before and after 5 days field training of urban fighters. In: K Hakkinen, H Kyro¨la¨inen, and R Taipale, eds. Proceedings of the Second International Congress on Soldiers’ Physical Performance, 2011 May 4–7. Jyva¨skyla¨, Finland: The Finnish Defense Forces, 2011. 10. Koulmann, N, Sanches, H, Pons, C, Simler, N, Pla, S, Cabelle, D, Cian, C, and Bigard, X. Evaluation of physiological and cognitive responses after 5 days of field survival conditions. In: K Hakkinen, H Kyro¨la¨inen, and R Taipale, eds. Proceedings of the Second International Congress on Soldiers’ Physical Performance, 2011 May 4–7. Jyva¨skyla¨, Finland: The Finnish Defense Forces, 2011. 11. Leyk, D, Rohde, U, Erley, O, Wunderlich, M, Ru¨ther, T, and Essfeld, D. Recovery of hand grip strength and hand steadiness after exhausting manual stretcher carriage. Eur J Appl Physiol 96: 593–599, 2006. 12. Lieberman, HR, Bathalon, GP, Falco, CM, Morgan, CA 3rd, Niro, PJ, and Tharion, WJ. The fog of war: Decrements in cognitive performance and mood associated with combat-like stress. Aviat Space Environ Med 76: 7–14, 2005. 13. Liu, Y, Higuchi, S, and Motohashi, Y. Changes in postural sway during a period of sustained wakefulness in male adults. Occup Med 51: 490–495, 2006. 14. Ma, J, Yao, YJ, Ma, RM, Li, JQ, Wang, T, Li, XJ, Han, WQ, Hu, WD, and Zhang, ZM. Effects of sleep deprivation on human postural control, subjective fatigue assessment and psychomotor performance. J Int Med Res 37: 1311–1320, 2009. 15. Mikulski, T, Tomczak, A, Lejk, P, and Klukowski, K. Influence of ultra long exercise and sleep deprivation on physical performance of healthy men. Med Sport 10: 98–101, 2006. 16. Morgan, ChA III, Hazlett, G, Doran, A, Garrett, S, Hoyt, G, Thomas, P, Baranoski, M, and Southwick, SM. Accuracy of eyewitness memory for persons encountered during exposure to highly intense stress. Int J Law Psychiatry 27: 265–279, 2004. 17. Rintama¨ki, H, Oksa, J, Rissanen, S, Kyro¨la¨inen, H, Keskinen, O, Kauranen, K, and Peitso, A. Physical activity during a 12 days military field training in winter and the effects on muscular and cardiorespiratory fitness. In: Strategies to Maintain Combat Readiness during Extended Deployments—A Human Systems Approach. Meeting Proceedings RTO-MP-HFM-124. Neuilly-sur-Seine, France: RTO, 2005. pp. 18; 18–1–18–6. Available at: http://www.rto.nato.int/ abstracts.asp. Accessed May 20, 2012. ´ 18. Sienkiewicz-Dianzenza, E, Tomaszewski, P, Iwanska, D, and Stupnicki, R. Anaerobic endurance of young untrained male and female subjects. Biomed Hum Kinetics 1: 16–19, 2009. 19. Taylor, MK, Stanfill, KE, Padilla, GA, Garrett, S, Hoyt, G, Thomas, P, Baranoski, M, and Southwick, SM. Effects of psychological skills training during military survival school: Randomized, controlled field study. Mil Med 176: 1362–1368, 2011. 20. Tomczak, A. Effects of winter survival training on selected motor indices. Biomed Hum Kinetics 2: 62–65, 2010. 21. Tomczak, A. Effects of 3-day survival training on selected coordination motor skills of special unit soldiers. Arch Budo 3: 168–172, 2013. 22. Tomczak, A and Stupnicki, R. An assessment of four tests used in military training. Biomed Hum Kinetics 6: 47–50, 2014. 23. Ziemba, AW, Chmura, J, Kaciuba-Uscilko, H, Nazar, K, Wisnik, P, and Gawronski, W. Ginseng treatment improves psychomotor performance at rest and during graded exercise in young athletes. Int J Sport Nutr 9: 371–377, 1999.
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General Staff of the Polish Armed Forces, Department of Physical Education and Sport, Warsaw, Poland; and 2University of Physical Education in Warsaw, Biala Podlaska, Poland ABSTRACT
Tomczak, A. Coordination motor skills of military pilots subjected to survival training. J Strength Cond Res 29(9): 2460– 2464, 2015—Survival training of military pilots in the Polish Army gains significance because polish pilots have taken part in more and more military missions. Prolonged exercise of moderate intensity with restricted sleep or sleep deprivation is known to deteriorate performance. The aim of the study was thus to determine the effects of a strenuous 36-hour exercise with restricted sleep on selected motor coordination and psychomotor indices. Thirteen military pilots aged 30–56 years were examined twice: pretraining and posttraining. The following tests were applied: running motor adjustment (15-m sprint, 3 3 5-m shuttle run, 15-m slalom, and 15-m squat), divided attention, dynamic body balance, handgrip strength differentiation. Survival training resulted in significant decreases in maximum handgrip strength (from 672 to 630 N), corrected 50% max handgrip (from 427 to 367 N), error 50% max (from 26 to 17%), 15-m sprint (from 5.01 to 4.64 m$s21), and 15-m squat (2.20 to 1.98 m$s21). The training improvements took place in divided attention test (from 48.2 to 57.2%). The survival training applied to pilots only moderately affected some of their motor adjustment skills, the divided attention, and dynamic body balance remaining unaffected or even improved. Further studies aimed at designing a set of tests for coordination motor skills and of soldiers’ capacity to fight for survival under conditions of isolation are needed.
KEY WORDS prolonged exercise, survival of soldiers, sleep deprivation, motor adjustment, running motor adjustment
INTRODUCTION
R
escuing soldiers lost in combats, and especially military pilots, has been one of prime military duties. Apart from immediate effects, i.e., bringing the rescued back to shape so as to engage
Address correspondence to Andrzej Tomczak, [email protected]. 29(9)/2460–2464 Journal of Strength and Conditioning Research Ó 2015 National Strength and Conditioning Association
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him/her again in military actions, rescuing greatly improves the morale of the unit. Such actions are sometimes publicized by mass media, e.g., the rescue of Capt. Scott O’Grady shot down in 1995 in Bosnia. Military survival training in the Polish Army has received special attention in recent years because of increased awareness that it is highly probable that Polish soldiers will need survival skills on military missions (20). In the Polish Air Forces, survival training lasting several days was organized by the Military Training and Physical Fitness Center for pilots. The training consists of theoretical and practical classes, as well as a final, 36-hour continuous field exercise. The last part of the training is especially onerous for military pilots given the necessity to act on the ground and in hostile surroundings. The pilots are evaluated by instructors throughout the training. The psychological, physiological, and fitness evaluation of the trainees is essential for comprehensive optimization of training curricula, and extensive research was conducted in that area (6,12,14), especially in prolonged survival training (4,9,10,17). Assessments of psycho-emotional effects were conducted for diverse activities at survival exercises consisting of simulated prison of war and close questioning (16). Other assessments pertained to prolonged exertions and sleep deprivation (1,4,15). After the Korean war in the fifties, SERE (Survival, Evasion, Resistance, Escape) trainings, closely imitating possible actions and behavior of the enemy, were initiated (5). Taylor et al. (19) assessed the capacity of soldiers subjected to psychological skill training (PST), including a selected combination of goal setting, arousal/ attention control, positive self-talk, and mental imagery, to cope with a simulated enemy and resistance to the various forms of simulated exploitation in stressful mock-captivityrelated training challenges. Some observable effects of the PST intervention were noted but future research in that area is needed. In another study on SERE that included being in a mock prisoner of war camp, the soldiers were assessed with respect to the accuracy of eyewitness’ memory (16). During prolonged military operations, it is vital that reaction times to simple and complex visual stimuli be as short as possible. Furthermore, visual-motor coordination and performance of attention tasks should also be maintained at a high level. In previous studies on the effects of
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survival instructors during winter survival training (20). Another TABLE 1. Mean values (6SD) of handgrip strength variables in male military pilots related factor is the differentia(n = 13) participating in survival training.* tion of hand strength after a proVariable Pretraining Posttraining z longed physical exercise. During a 36-hour survival exercise for Max 672 6 268 630 6 249† 20.15z young men, a decrease of the 50% max 427 6 187 367 6 147† strength correction factor to Corrected 50% max 371 6 168 324 6 147† Error 50% max (%) 26 6 15 17 6 10 20.42z 50% of maximum strength was Error corr. (%) 11 6 9§ 7 6 5§ noted, the maximum strength PI max 0.905 6 0.045 0.905 6 0.051 0.00 remaining unchanged (4). HowPI 50% 0.798 6 0.091k 0.832 6 0.088k 0.36 ever, during a 5-day field trainPI corr. 0.853 6 0.083 0.831 6 0.044k 20.27 ing, a decrease in maximum *PI = performance index; z = standardized variable (day 2 vs. day 1). strength was reported while the †Significantly different from day 1: p # 0.05. maximum leg strength remained zp # 0.05. §Significantly (p , 0.01) different from error 50% max. unchanged (9). kSignificantly (p , 0.01) different from PImax. Despite extensive studies on the effects of different conditions of military service on psychophysical performance, a moderate-intensity survival training lasting 36 hours, no no reports on military pilots subjected to prolonged survival deterioration of visual coordination (17) or of multipletraining were found in the available literature. Thus, the aim choice reaction time (MCRT) (14) were noticed. However, of this study was to determine the selected coordination the highest levels of MCRT were found at about 70–80% of motor skills of military pilots subjected to long-lasting V_ O2max in graded exercise tests to exhaustion (23). survival training. Reports on the effects of prolonged survival training on the METHODS sense of balance are scarce. Posturographic analysis (7,14) and rotation tests (4,21) were conducted after overnight training, Experimental Approach to the Problem and both static and dynamic balance ability were found to To assess the impact long-lasting survival training has on the decline. Other authors also reported negative effects of sleep selected coordination motor skills; military pilots were deprivation (without physical load) on the state of balance. subjected for this study. Subjects were military pilots with Disorders in balance were also reported when testing was many years of military service. Before all testing, subjects undertaken in the early morning hours (2,13). were required to be rested and abstain from strenuous exercise for at least 24 hours. In the morning, before the Motor coordination, agility, and speed are factors that start of training, prestudy measurements were performed, determine the efficacy in close combat. Motor adjustment tests, that include those factors, were applied to candidates for and later began the 36-hour survival training. Immediately after completion of the training were conducted poststudy measurements. During the test set handgrip strength, divided TABLE 2. Mean (6SD) and standardized (z) values of motor coordination attention, motor adjustment variables in male military pilots (n = 13) participating in survival training.* skills, dynamic body balance. Variable Pretraining z Posttraining z The degree of changes was estimated. 15-m Sprint (SS) 5.01 6 0.43 0.08 4.64 6 0.51† 21.10z 3 3 5-m Shuttle run (SR) 15-m Slalom (SL) 15-m Squat (SQ) Divided attention [%] Rotational test [%]
3.15 2.85 2.20 48.2 67.9
6 6 6 6 6
0.24 0.29 0.60 16.5 17.3
0.39 21.96§ 21.68§
3.03 2.84 1.98 57.5 61.5
6 6 6 6 6
*SS = straight sprint; SR = shuttle run; SL = slalom; SQ = squat. †Significantly different from Day 1: p , 0.001. zp # 0.05. §p , 0.001. kSignificantly different from Day 1: p , 0.01. ¶Significantly different from Day 1: p # 0.05.
0.31 0.27 0.46k 23.4¶ 19.3
0.94§ 20.84z 22.09§
Subjects
Thirteen military pilots aged 36.3 6 8.3 years and being in service for 17.3 6 8.8 years, volunteered to take part in the study. Their mean body height was 181 6 5.6 cm, mean body weight was 83.4 6 6.7 kg, and BMI 25.6 6 2.2 kg$m22. The subjects provided their written
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Coordination Motor Skills of Military Pilots
TABLE 3. Mean values (6SD) of speed-strength (W1) and speed-agility (W2) indices in male military pilots (n = 13) participating in survival training. Index W1 W2
Pretraining
Posttraining
20.80 6 1.04* 20.79 6 0.81§
21.59 6 1.09†z 0.05 6 0.86k¶
*Significantly different from zero: p # 0.05. †Significantly different from zero: p , 0.001. zSignificantly different from the pre-training value: p , 0.001. §Significantly different from zero: p , 0.01. kSignificantly different from the pre-training value: p , 0.01. ¶Significantly (p , 0.01) different from W1.
consents, and the study was approved by the Ethics Committee of the Medical University in Warsaw. Procedure
The training consisted of the following tasks: mountain walking for a few hours with elements of climbing (abseiling rope, making knots), transport of a wounded companion on stretcher, constructing shelters, lighting fire, a night march on azimuth, orienteering and crossing a rope bridge; the total distance covered amounting to 22–24 km. The study consisted of a 36-hour continuous survival training conducted in a submontane area in winter. The temperatures ranged from 248C during the day to 2108C at night; there was no snowfall or strong wind. The pilots carried rucksacks containing basic military equipment weighing 10–12 kg throughout the training. The subjects received a supply of dry provisions and had unlimited access to drinking water. They slept for 2-3 hours in self-built shelters. The estimated total energy expenditure amounted to about 8600 kcal per subject. The tests were applied on the day before training (pretraining) and then after 36 hours, i.e., directly at the end of training (posttraining). All measurements were conducted under identical conditions in sports hall. The following measurements were conducted: 1. Handgrip strength 2. Divided attention 3. Motor adjustment skills (22) 4. Dynamic body balance (8). Handgrip Strength. Handgrip strength (in N) was determined with the use of PZA/3359 dynamometer (Fabrication Enterprises Inc., Elmsford, NY, USA) held in the preferred hand, in standing posture, arms along the trunk. Three tasks were performed to measure the force differentiation skill— maximum strength, an attempt at performing 50% of the maximum, and then a corrective attempt at performing the requested 50%. Every task was repeated 5 times and averaged. The results were presented as maximum force and as relative differences between the actual outcome and the re-
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quested 50% value (50% max and correction errors). In addition, from the 5 repetitions of maximum handgrip, the performance index (PI) was computed (18). This reflected the capacity to maintain the peak force in all 5 repetitions.
Divided Attention. Two types of signals were displayed on the screen: the first type contained shapes (a square, a circle, or a cross) placed in the central part of the monitor. When they were displayed in the above sequence, the “+” key was to be pressed with the right thumb (or the “Q” key with the left thumb). All other sequences were incorrect. The second type of signals consisted of small squares displayed in the various corners of the monitor. If 4 squares were displayed simultaneously in one of the corners, the “–” key was to be pressed with the right index finger (or the “l” key with the left index finger). After the test was completed, the numbers of correct attempts were displayed in the central part of the monitor, and the numbers of errors (omitted signals and incorrectly pressed keys) and percent ratios in the corners. The percent ratio of correct reactions to the sum of correct and erroneous ones was the test result. Motor Adjustment. The running tests were as follows: 15-m straight sprint (SS), shuttle run 3 3 5-m (SR; standing start), 15-m slalom run (SL; first pole at a 5-m distance from the start, the remaining 4 spaced by 1.2 m; standing start), and 15-m squat (SQ, crouching start). Running times were recorded electronically with 0.01-second accuracy; the results were presented as velocities (15 / time) and as standardized values. From those standardized values, the speed-strength (W1) and speed-agility (W2) indices were computed: W1 = (zSS + zSQ) / 2, W2 = (zSR + zSL) / 2 (18). Dynamic Body Balance. A rotation test was applied; a subject stood on the line and attempted to perform a jump with full rotation (alternately clockwise and counterclockwise, repeated 3 times) and landed with both feet on the line in ;12 seconds at a constant rhythm; 6 training jumps being allowed. The accuracy of landing and maintaining the balance was scored (0 – clean jump, 1 – 1 foot off the line, 2 – both feet off the line, 3 – lost balance with hand support) and summarized from 6 jumps (score range from 0 – excellent to 18 – unsatisfactory). Statistical Analyses
Kolmogorow-Smirnow’s test was used to check the normality of distributions. The velocities were standardized using the following equations (22):
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Journal of Strength and Conditioning Research zSS ¼ ðSS24:98Þ=0:31 zSQ ¼ ðSQ23:09Þ 0:53 zSR ¼ ðSR20:616$SSÞ=0:18 zSL ¼ ðSL20:651$SSÞ=0:21: The between-day differences in mean values were assessed using Student’s t test for dependent measures. Statistica 6.0 software was used in data analysis, the level of p # 0.05 being considered significant.
RESULTS The results are presented in Tables 1–3. Maximum handgrip strength significantly decreased posttraining (by ;6%; t = 2.23, p , 0.046). Mean percent errors of correcting the requested attempts at 50% of the maximum handgrip (error corr.) were markedly lower (8 6 12 vs. 26 6 15 and 1 6 9 vs. 17 6 11, preand post-training, respectively) than those of the first attempt (error 50% max). Moreover, both errors were markedly lower posttraining than pretraining (17 6 11 vs. 26 6 15 and 1 6 9 vs. 8 6 12, respectively; see Table 1). The PI, a measure of task precision, did not significantly change posttraining. The applied survival training resulted in significant decreases in the SS and SQ runs (by 7%, p , 0.001, and by 10%, p , 0.01, respectively) and in a significant improvement (by 19%, p # 0.05) in the divided attention test. No significant differences were found for SR and SL runs or for the rotational test results. However, standardized (vs. reference values used in equations) velocities of SR and SL runs revealed a marked posttraining improvement in the SR run (Table 2). When the standardized results of running tests were converted to W1 and W2 indices, the speed-strength index (W1) that was lower from the reference value pretraining (p # 0.05) decreased further posttraining (p , 0.001). However, the speed-agility index (W2) that was also lower from the reference value pretraining (p , 0.01) significantly improved posttraining (p , 0.01) and attained the reference level (z = 0.05; Table 3). No significant correlations of the variables studied with BMI values were found either pre- or post-training.
DISCUSSION Coordination skills and psychomotor performance are of utmost importance for military pilots. In addition, highperformance aircraft pilots should be prepared for acceleration tolerance and, for that reason, particular emphasis is placed on strength training and special gymnastics L1, i.e., shaping the anaerobic potential. However, military pilots ought to be prepared to carry out SERE-related tasks including the survival training. It specifically involves prolonged stays under extreme conditions, e.g., after being shot down or after an emergency landing in an enemy area, going long distances on foot, etc. (17,21).
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A high performance of military tasks related to psychomotor agility, attention focusing, reaction time, perception, and visual-motor coordination, depends on factors such as age, work experience, vigilance, and mood (12,17,18). It was demonstrated (14,18) that a prolonged application of exercise combined with sleep deprivation did not affect the psychomotor performance of civilians. In this study, military pilots attained better results of the divided attention test immediately post- than pre-training, and the same was true for the handgrip force differentiation skill. This was probably due to pilots’ experience in performing under diverse conditions of weather, training, and military actions. The pilots had to make use of all skills assessed by the applied tests, and their attention focusing was more intense than in performing daily activities; working under the pressure of time and of the unpredictability of events, they did their best to accomplish every task as if they fought for life. In that way they achieved skills necessary in dangerous circumstances. The obtained results seem to comply with the first law of Yerkes-Dodson, according to which the relation between the task performance and emotional stimulation is nonlinear, i.e., both too low or too high stimuli impair the performance. In other words, the loads the pilots were subjected to were fully tolerable. The psychomotor skills desired when functioning in isolation include differentiation of hand strength that can be useful when performing injection, operating mobile radio station, using weapon, etc. Another factor important in military actions is the recovery rate after upper extremity exertions. Leyk et al. (11) reported that subjects who, under laboratory conditions, executed a task consisting of carrying a load of 50 kg over a distance of about 264 m in about 215 seconds experienced fatigue of upper extremities and a decrease of maximum strength that persisted over the next day. However, hand steadiness returned back to normal 30 minutes postexertion. Such a situation may happen in real actions, e.g., in emergency landing on enemy’s territory when one of the pilots gets injured. When the activities performed under difficult conditions persist, the performance deteriorates. In this study, the activities lasted 36 hours and no deterioration of psychomotor performance was noted. However, when survival training lasted as long as 53 or 73 hours and was combined with sleep deprivation, marked decreases in psychomotor tests and in the Profile of Mood States were observed (12). Commanding officers have to know how long it takes a soldier to start losing his/her psychomotor and work capacity and what is his/her general state. That knowledge would enable assessing soldier’s capacity to function in a rescue action. Motor adjustment tests applied in this study are informative with respect to the motor potential at short distances; good results of those tests are indicative of a high fitness in sudden changes of the running course, in crawling, in secretive approaches, etc. Mastering such behaviors is necessary in close-range combats, in settled areas, etc. Most test results attained by pilots in this study were negatively affected by the survival training, the 15-m VOLUME 29 | NUMBER 9 | SEPTEMBER 2015 |
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Coordination Motor Skills of Military Pilots SQ being an exception. In contrast, physical education students who underwent comparable loads exhibited decreased posttraining results only in the 15-m sprint, other runs remaining unaffected (20). The pilots were, however, by 14 years (on average) older than students, and the speed-agility skills are known to be age-dependent. In case of dynamic equilibrium, no significant differences between the pre- and post-training results were noted in pilots, whereas in physical education students the training load negatively affected their capacity to maintain balance (4). Huang et al. (7) reported that in civilians, subjected to carrying military equipment and thus fatigued, the mediolateral sway and the resulting postural sway were increased and that could enhance the risk of injury. Such disorders could impair safe functioning of pilots, e.g., readiness to undertake forced march, to leap away from the landing spot, to move at close range in a fight, etc., but the pilots in this study proved sufficiently well-trained.
PRACTICAL APPLICATIONS The subject discussed in this article is fairly novel; the presented data gave an insight into the effects of prolonged exercise combined with restricted sleep applied to military pilots on their performance in several psychomotor tests. It seems that to provide effective execution of precise tasks during military action coordination and strength endurance trainings should be introduced in soldiers’ drills. However, the reports on that subject are very scarce, and this calls for undertaking further studies aimed at designing a set of tests for coordination motor skills and of soldiers’ capacity to fight for survival under conditions of isolation.
ACKNOWLEDGMENTS The author thanks military pilots for their committed participation in the study and to Prof. R. Stupnicki for his expert statistical advice.
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