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Johnson, CD, Whitehead, PN, Pletcher, ER, Faherty, MS, Lovalekar, MT, Eagle, SR, and Keenan, KA. The relationship of core strength and activation and performance on three functional movement screens. J Strength Cond Res 32(4): 1166-1173, 2018-Current measures of core stability used by clinicians and researchers suffer from several shortcomings. Three functional movement screens appear, at face-value, to be dependent on the ability to activate and control core musculature. These 3 screens may present a viable alternative to current measures of core stability. Thirty-nine subjects completed a deep squat, trunk stability push-up, and rotary stability screen. Scores on the 3 screens were summed to calculate a composite score (COMP). During the screens, muscle activity was collected to determine the length of time that the bilateral erector spinae, rectus abdominis, external oblique, and gluteus medius muscles were active. Strength was assessed for core muscles (trunk flexion and extension, trunk rotation, and hip abduction and adduction) and accessory muscles (knee flexion and extension and pectoralis major). Two ordinal logistic regression equations were calculated with COMP as the outcome variable, and: (a) core strength and accessory strength, (b) only core strength. The first model was significant in predicting COMP (p = 0.004) (Pearson's Chi-Square = 149.132, p = 0.435; Nagelkerke's R-Squared = 0.369). The second model was significant in predicting COMP (p = 0.001) (Pearson's Chi-Square = 148.837, p = 0.488; Nagelkerke's R-Squared = 0.362). The core muscles were found to be active for most screens, with percentages of "time active" for each muscle ranging from 54-86%. In conclusion, performance on the 3 screens is predicted by core strength, even when accounting for "accessory" strength variables. Furthermore, it seems the screens elicit wide-ranging activation of core muscles. Although more investigation is needed, these screens, collectively, seem to be a good assessment of core strength.

The current U.S. Navy Physical Readiness Test (PRT) measures aerobic fitness and muscular endurance via a 1 1/2 mile run and curl-up/push-up tests, respectively. Nine new modalities were recommended to either replace or supplement the current PRT. Personnel and civilians (N = 179) were recruited from a local Navy base and participated in all modalities (duplicate if possible) over 4 weeks following familiarization sessions. Subjects performed single-leg plank, single-leg wall squat, cadence push-ups, leg/hip dynamometer, standing long jump, and pro-agility test. Cardiovascular modalities were also performed via the 300-yard shuttle, 2-km row, and 5-km bike. Performance in the modalities was correlated to the subjects' existing PRT scores as well as within the new modalities. Although most modalities could not be concretely recommended, the plank and wall squat were eliminated from consideration because of poor reliability scores. The strongest correlation existed between the standing long jump and pro-agility test for the entire sample. Correlation scores were also analyzed by gender. The cardiovascular modalities did not have strong enough scores to elicit a recommendation to replace the 1 1/2 mile run, but future considerations for similar testing would be to collect scores for the existing modalities in addition to the proposed modalities.