Study: NCT02780739

Intervention type: BEHAVIORAL
Group type: EXPERIMENTAL
Intervention: Fitness
Description: Based on high intensity cardiovascular resistance training (HICRT), this intervention includes a combination of aerobic and strength training. Sessions are conducted in a group of ≤20 participants per class, with ≤5 participants per trainer. This intervention includes 28 70-min sessions (32.67 hrs) completed over 16 weeks: 3/wk weeks 1-4, 2/wk weeks 5-8, 1/wk weeks 9-16. At the first and last session, participants complete the Army Physical Readiness Test. All other sessions consist of: Warm-up; Walk/Run; 2 HICRT circuits with 3 sets of 3-4 exercises; 1-2 min jump rope and 4-min power series between HICRT segments; Drills \& Skills; and Cool-down/stretch.

Intervention type: BEHAVIORAL
Group type: EXPERIMENTAL
Intervention: Fitness
Description: Based on high intensity cardiovascular resistance training (HICRT), this intervention includes a combination of aerobic and strength training. Sessions are conducted in a group of ≤20 participants per class, with ≤5 participants per trainer. This intervention includes 28 70-min sessions (32.67 hrs) completed over 16 weeks: 3/wk weeks 1-4, 2/wk weeks 5-8, 1/wk weeks 9-16. At the first and last session, participants complete the Army Physical Readiness Test. All other sessions consist of: Warm-up; Walk/Run; 2 HICRT circuits with 3 sets of 3-4 exercises; 1-2 min jump rope and 4-min power series between HICRT segments; Drills \& Skills; and Cool-down/stretch.

Intervention type: BEHAVIORAL
Group type: ACTIVE_COMPARATOR
Intervention: Active Control
Description: The active control condition consists of 2 tasks (change detection and visual search) with 3 variants each. This intervention includes 48 70-min sessions (56 hrs) completed over 16 weeks: 3/wk. The 6 tasks are played in random order for 10 min each session.

Intervention type: DEVICE
Group type: EXPERIMENTAL
Intervention: active tDCS
Description: Active HD-tDCS is administered during the first 30 minutes of each Mind Frontiers session. Therefore, the schedule is 20 30-min sessions (10 hrs) completed over 12 weeks: 1/wk weeks 5-8, 2/wk weeks 9-16. The HD-tDCS devices are Soterix Medical 2x2 models, using 4 electrodes (2 anodal and 2 cathodal). Electrodes are held in place with custom, 3D-printed electrode holders inserted into EEG caps, using EEG gel. Participants receive 2.0 mA current for 30 min, split over the 2 anodal electrodes, each drawing ≤1.0 mA. Stimulation is ramped up and ramped down over 30 sec at the beginning and end of the 30-min stimulation period.

Intervention type: DEVICE
Group type: EXPERIMENTAL
Intervention: sham tDCS
Description: Sham HD-tDCS is administered during the first 30 minutes of each Mind Frontiers session. Therefore, the schedule is 20 30-min sessions (10 hrs) completed over 12 weeks: 1/wk weeks 5-8, 2/wk weeks 9-16. The HD-tDCS devices are Soterix Medical 2x2 models, using 4 electrodes (2 anodal and 2 cathodal). Electrodes are held in place with custom, 3D-printed electrode holders inserted into EEG caps, using EEG gel. Participants do not receive sustained stimulation; it is ramped up and ramped down over 30 sec at the beginning and end of the 30-min stimulation period to elicit the sensation of simulation and make the sham condition more convincing.

Intervention type: BEHAVIORAL
Group type: EXPERIMENTAL
Intervention: Cognitive Training - 20 sessions
Description: Mind Frontiers cognitive training software (Aptima Inc.) is a Wild West-themed Android application played on Nexus 10 tablets. This intervention includes 20 70-min sessions (23.33 hrs) completed over 12 weeks: 1/wk weeks 5-8, 2/wk weeks 9-16. The 6 mini-games, played in random order for 10 min each session, are Ante Up (Tower of London, executive functioning); Irrigator (visuospatial reasoning); Pen 'Em Up (dual task switching, executive function); Supply Run (Keep Track, working memory updating); Riding Shotgun (visuospatial working memory); and Sentry Duty (dual n-back, working memory). There is also a meta-game in which players build a town using resources earned from the mini-games, played for 5 min each session.

Intervention type: BEHAVIORAL
Group type: EXPERIMENTAL
Intervention: Cognitive Training - 20 sessions
Description: Mind Frontiers cognitive training software (Aptima Inc.) is a Wild West-themed Android application played on Nexus 10 tablets. This intervention includes 20 70-min sessions (23.33 hrs) completed over 12 weeks: 1/wk weeks 5-8, 2/wk weeks 9-16. The 6 mini-games, played in random order for 10 min each session, are Ante Up (Tower of London, executive functioning); Irrigator (visuospatial reasoning); Pen 'Em Up (dual task switching, executive function); Supply Run (Keep Track, working memory updating); Riding Shotgun (visuospatial working memory); and Sentry Duty (dual n-back, working memory). There is also a meta-game in which players build a town using resources earned from the mini-games, played for 5 min each session.