Nutritional Requirements During Training for Special Operation Forces – An Observational Study

Abstract

Background: Responses to exercise training can vary greatly between individuals. For special operation forces, low responses to training can hamper performance. In this study, we objectively measured strength and fitness during special operation forces training, and assessed potential determinants of the training response. Methods: Twenty subjects were enrolled, and measurements were taken before and after a 9-week training program. Muscular strength was measured as one-repetition-maximum on four instruments, and physical fitness by the Cooper-test. Body composition was measured using deuterium dilution, physical activity by accelerometry and diet quality by food records. Level of significance was p<0.05.Results: During the 9-week training period, body strength increased by 0.33±0.24 N/kg (+7%, P<0.001, and physical fitness increased by 3.5±3.4 mL/min/kg (+6%, P=0.001). Gains in strength were inversely associated with strength at baseline, and positively with activity intensity during the training program. We observed no effect of training on body weight, but body composition was significantly different at follow-up as compared to baseline (16.9±2.5% to 14.9±2.5% body fat, P=0.03). Energy intake was 4491±506 kcal/d and energy balance was -243±306 kcal/d (P=0.04). Average physical activity level was 2.6±0.2 and the average duration of moderate-to-vigorous physical activity was 5:53±0:36h. Over time, physical activity did not change significantly. After adjustment for underreporting, intakes of vitamin C and D were insufficient on average and for most participants.Conclusions: Improvements in strength were modulated by strength prior to the intervention, and moderate-to-vigorous physical activity during the training. Thus, compensatory declines in physical activity may hamper the effectiveness of the exercise program.

Lessons From Special Forces Operators for Elite Team Sports Training: How to Make the Whole Greater Than the Sum of the Parts

“…Body weight (BW) and body fat percentage (F%) were measured by using a bioelectrical impedance analysis (BIA, TANITA-BC-418 Segmental Body Composition Analyzer), with consideration of the measurement of weight up to the nearest 0.1 kg. These variables were measured because a prolonged intensive period of training can lead to an overall negative energy balance and low energy availability (Mullie et al, 2019 ; Rietjens et al, 2021 ). This low energy availability can lead to reductions in body weight (BW) and changes in body composition, which can impact both health and performance (Tassone and Baker, 2017 ).…”

“…In the context of SOF, the main challenge is not to determine precisely how to scientifically investigate what optimum type of nutrition should be offered. Several comprehensive sources already exist that cover the topic (e.g., Deuster et al, 2017 ; Rietjens et al, 2021 ). The main issue is a practical one, which can be summarized as timing (of food intake) and availability (of food of sufficient quality in sufficient quantity).…”

“…Physical activity is so paramount in both the function of the operator but also his coping mechanism (Huret, 2018 ) that we addressed it separately. Regarding nutrition and sleep, as there were no institutional programs within Defense in these areas at the time, we distributed them within the experts team: nutrition would be addressed by the Dutch exercise physiologist consulting for the program (who had the expertise of implementing a nutrition optimization program within the Dutch SOF unit, e.g., Rietjens et al, 2021 ), the MD and the physical training instructor (PTI); and sleep would be addressed by the MD (who had the expertise of decades of research regarding sleep in extreme environments, e.g., Pattyn et al, 2018 ) and the performance psychologist. Lack of education was addressed in our pilot project, as well as lack of support and guidance.…”