Velocity Drives Greater Power Observed During Back Squat Using Cluster Sets.

This investigation compared the kinetics and kinematics of cluster sets (CLU) and traditional sets (TRD) during back squat in trained (RT) and untrained (UT) men. Twenty-four participants (RT = 12, 25 ± 1 year, 179.1 ± 2.2 cm, 84.6 ± 2.1 kg; UT = 12, 25 ± 1 year, 180.1 ± 1.8 cm, 85.4 ± 3.8 kg) performed TRD (4 × 10, 120-second rest) and CLU (4 × (2 × 5) 30 seconds between clusters; 90 seconds between sets) with 70% one repetition maximum, randomly. Kinematics and kinetics were sampled through force plate and linear position transducers. Resistance-trained produced greater overall force, velocity, and power; however, similar patterns were observed in all variables when comparing conditions. Cluster sets produced significantly greater force in isolated repetitions in sets 1-3, while consistently producing greater force due to a required reduction in load during set 4 resulting in greater total volume load (CLU, 3302.4 ± 102.7 kg; TRD, 3274.8 ± 102.8 kg). Velocity loss was lessened in CLU resulting in significantly higher velocities in sets 2 through 4. Furthermore, higher velocities were produced by CLU during later repetitions of each set. Cluster sets produced greater power output for an increasing number of repetitions in each set (set 1, 5 repetitions; sets 2 and 3, 6 repetitions; set 4, 8 repetitions), and the difference between conditions increased over subsequent sets. Time under tension increased over each set and was greater in TRD. This study demonstrates greater power output is driven by greater velocity when back squatting during CLU; therefore, velocity may be a useful measure by which to assess power.

The Effect of Physical Readiness Training on Reserve Officers' Training Corps Freshmen Cadets.

BACKGROUND: The U.S. Army Reserve Officers' Training Corps (ROTC) is the largest commissioning source among all branches. Physical Readiness Training (PRT) is fundamental to ROTC cadet training. However, although studies have evaluated the effectiveness of PRT in cadets with prior PRT experience, no study has examined the early phase adaptations in those cadets with no prior PRT experience. METHODS: To determine the effect of PRT over the course of an academic year (9 months) in freshmen ROTC cadets, thirteen (n = 13; 7 male [180.8 ± 4.7 cm, 77.4 ± 10.0 kg; 19.8 ± 6.5 % body fat], 6 female [159.5 ± 12.1 cm; 63.4 ± 8.4 kg; 29.6 ± 6.2% body fat]) cadets with no prior PRT performed laboratory (body composition, 1-repetition maximum [1RM] bench and squat, countermovement vertical jump, maximal aerobic capacity [VO2max]) and field-based ([Army Physical Fitness Test (APFT) (2 minutes maximum push-ups and sit-ups, 2-mile run)]) measures of performance before (PRE), mid-year (MID), and at the conclusion of the academic year (POST). PRT was performed 3 times per week in accordance with Army standards. FINDINGS: No changes occurred in body composition, VO2max, or countermovement vertical jump. 1RM bench improved at MID in men (PRE, 78.5 ± 8.4 kg; MID, 84.7 ± 8.0 kg) and women (PRE, 42.0 ± 10.2 kg; MID, 46.2 ± 10.9 kg) with no further improvement. Women improved 1RM back squat (PRE, 55.3 ± 13.5 kg; POST, 74.6 ± 14.6 kg) and APFT tests: push-ups (PRE, 27 ± 10; POST, 39 ± 12), sit-ups (PRE, 55 ± 19; POST, 74 ± 12), 2-mile run (PRE, 18.6 ± 2.9; POST, 17.2 ± 1.3 minutes); although men improved in push-ups (PRE, 54 ± 6; POST, 67 ± 8) and sit-ups (PRE, 63 ± 8; POST, 75 ± 9). DISCUSSION/IMPACT/RECOMMENDATIONS: Nine months of PRT improved APFT scores of freshmen cadets while minor effects were noted in laboratory-based performance. Given the lack of improvements in strength and power, it would be advisable to provide supplemental strength and power training. Being a large commissioning resource for the Army with greater access to equipment and resources, the time spent in ROTC may be a unique opportunity to improve and educate young commissioning officers on the benefits of proper strength and power training for the use in future commands while units are considerably smaller and equipment is more accessible on university grounds.