Is there a low-back cost to hip-centric exercise? Quantifying the lumbar spine joint compression and shear forces during movements used to overload the hips

The aim of this study was to quantify joint compression and shear forces at L4/L5 during exercises used to overload the hips. Nine men performed 36 "walking" trials using two modalities: (1) sled towing and (2) exercise bands placed around the ankles. Participants completed forward, backward, and lateral trials with bent and straight legs at three separate loads. Surface electromyography (EMG) was recorded bilaterally from eight torso and thigh sites, upper body and lumbar spine motion were quantified, and hand forces were measured. An EMG-driven musculoskeletal model was used to estimate the muscular contribution to joint compression and shear. Peak reaction, muscle and joint compression and shear forces, and peak gluteus medius and maximus activity were calculated. Significant differences were noted in each dependent measure; however, they were dependent on direction of travel, leg position, and load. The highest joint compression and shear forces for the sled and band conditions were 4378 N and 626 N, and 3306 N and 713 N, respectively. In general, increasing the band tension had little effect on all dependent measures, although a load-response was found during the sled conditions. Before using any exercise to improve hip function, the potential benefits should be weighed against "costs" to neighbouring joints.     

Critically Reflecting on the Origins,Evolution, and Impact of the Cattell-Horn-Carroll (CHC) Model

ABSTRACT

The Cattell-Horn-Carroll (CHC) model presently serves as a blueprint for both test development and a taxonomy for clinical interpretation of modern tests of cognitive ability. Accordingly, the trend among test publishers has been toward creating tests that provide users with an ever-increasing array of scores that comport with CHC. However, an accumulating body of independent research on modern intelligence tests has questioned many instruments’ alignment with the CHC model. To shed potential insight on these discrepancies, we review the developmental history of CHC and its numerous modifications from 1997 to the present. Next, we identify and discuss several potential limitations in the CHC literature that may be responsible for this discrepancy. Finally, we encourage clinicians to consider the extant evidence currently available for engaging in CHC-inspired assessment applications (e.g., XBA, PSW).     

Self-Esteem, Locus of Control, College Adjustment, and GPA Among First- and Continuing-Generation Students: A Moderator Model of Generational Status

The role of generational status (first-generation vs. continuing-generation college students) as a moderator of the relationship between psychological factors and college outcomes was tested to determine whether generational status acts as a risk factor or as a sensitizing factor. The sample consisted of 322 undergraduate students who completed online measures of self-esteem, locus of control, and academic adjustment and provided self-reports of GPA. Generational status significantly moderated the relationship between psychological factors and academic outcomes. Generally, it was found that the relationship between psychological factors and academic outcomes were strongest among first-generation students. Further, it was found that for the majority of the interactions with locus of control, first-generation status acted as a sensitizing factor that amplified both the positive and negative effects of locus of control. In contrast, for self-esteem, first generation status acted as a risk factor that only exacerbated the negative effects of low self-esteem. These results are interpreted as reflecting motivational differences between first- and continuing-generation students and are discussed with respect to the social/cultural capital hypothesis that is most frequently presented in the existing literature.     

The effect of short-term isometric training on core/torso stiffness

“Core” exercise is a basic part of many physical training regimens with goals ranging from rehabilitation of spine and knee injuries to improving athletic performance. Core stiffness has been proposed to perform several functions including reducing pain by minimising joint micro-movements, and enhancing strength and speed performance. This study probes the links between a training approach and immediate but temporary changes in stiffness. Passive and active stiffness was measured on 24 participants; 12 having little to no experience in core training (inexperienced), and the other 12 being athletes experienced to core training methods; before and after a 15 min bout of isometric core exercises. Passive stiffness was assessed on a “frictionless” bending apparatus and active stiffness assessed via a quick release mechanism. Short-term isometric core training increased passive and active stiffness in most directions for both inexperienced and experienced participants, passive left lateral bend among experienced participants being the exception (P < 0.05). There was no difference between the inexperienced and experienced groups. The results confirm that the specific isometric training exercise approach tested here can induce immediate changes in core stiffness, in this case following a single session. This may influence performance and injury resilience for a brief period.     

Exploring the latent structure of the Luria model for the KABC‐II at school age: Further insights from confirmatory factor analysis

The present study examined the factor structure of the Luria interpretive model for the Kaufman Assessment Battery for Children‐Second Edition (KABC‐II) with normative sample participants aged 7–18 (N = 2,025) using confirmatory factor analysis with maximum‐likelihood estimation. For the eight subtest Luria configuration, an alternative higher‐order model with Pattern Reasoning being permitted to cross‐load on the Planning and Simultaneous Processing factors provided the best fit to the normative sample data. Variance apportionment suggests that additional consideration, beyond the omnibus Mental Processing Index, of the contribution of the first‐order factor‐based scores (i.e., SQ, SM, P, and L), and in some cases the individual subtests themselves, may be warranted. Implications for clinical interpretation and the anticipated normative update of the measurement instrument are discussed.