Inter-day session reliability of a novel assessment for rotational power of the pelvis, spine and trunk

Purpose: The proximal musculature of the pelvis, spine and trunk play a key role in modulating forces to and from the extremities and the environment. Many field tests are designed to assess isometric muscular endurance tasks but are limited in assessing inter-day session reliability of rotational muscular power at the proximal segments. Methods: Inter-session reliability was assessed over three separate test sessions 7 days apart using the inline lunge ball toss (ILBT), isometric muscular endurance prone (IMEP) and side (IMES) plank tests in twenty-one females and twenty-two male college aged recreational athletic volunteers, (N=43). Results: Intraclass correlation coefficients were highly reliable for the ILBT (range, 0.72–0.99), the IMEP (range, 0.60–0.96) and moderate to high for the IMES (range, 0.62–0.88) between test sessions. Correlations relationships between the ILBT, IMEP and IMES were low to moderate (r range, 0.268 to 0.587). Conclusions: The ILBT was reliable and appeared to have a limited intersession learning effect over two weeks of testing. The stability and power component of the ILBT offer a reliable and comprehensive assessment protocol. Correspondence to: Thomas G. Palmer, PhD, ATC, CSCS*D, University of Cincinnati, Assistant Professor, College of Allied Health Sciences, Department of Rehabilitation Sciences, Room 275 French Hall East, 3202 Eden Ave., Cincinnati, OH 45267-0394, USA; Tel: 513-558-3766; E-mail: rehabsci@ucmail.uc. edu Received: May 12, 2017; Accepted: June 05, 2017; Published: June 08, 2017 Introduction Maximizing force production in a safe manner during sport is greatly predicated upon by the incremental stability and mobility of the proximal muscles that support the pelvis, spine and trunk. These muscles play a critical role in creating and transferring forces to and from the body and the environment. The unique motor control patterns between the deep and superficial proximal musculature supporting the pelvis, spine and trunk make it possible for athletes to perform skills at various intensities with diverse movement patterns [1-3]. The deep spinal muscles, such as the transverse abdominis or the quadratus lumborum, act in an anticipatory nature to support and prepare the lumbar spine to absorb and transfer forces milliseconds prior to distal muscle activations about the trunk and pelvis [4]. These spinal muscles have an intimate relationship with the vertebral segments and act as riggers to provide a proximal foundation for movement and force distribution to and from the proximal and distal segments. Deficits in motor control patterns or muscle weakness have been reported to disrupt the efficiency of force distribution, sport performance and contribute to injurious mechanisms [5]. As a result, health care professionals often implement assessment techniques designed to test the functional integrity of the proximal segments. Low levels of deep spinal muscle activation have been reported to stabilize and maintain postures of the lumbar spine regardless of the intensity or movement pattern performed [3,6]. Identified predominately as endurance based muscles the assessment techniques used to test the spinal stabilizers have been isometric endurance tasks, such as, static planks or the Biering-Sorensen test [7]. Despite a sequential learning effect over time static plank tests are reliable following a familiarization period and offer good insight as to the muscular endurance characteristics of the spinal stabilizers. However, the proximal musculature has recently been identified to have task specific characteristics regarding the mobility and bioenergetics demands necessary to complete a given task [3,8]. Plank tests offer limited insight to rotational and/or power movements common to acts of daily living and sport [8]. As a result, various ball toss tasks with different seated and standing positions have been proposed to assess the rotational power of the proximal segments. However, recent literature has struggled to find a field test with consistency in testing protocols, psychometric properties and inter-session reliability [3,6,9]. A primary contributor to these inconsistencies are the seated and standing positions that lack control of extremities and/or various degrees of freedom throughout the kinetic chain that allow for a variety of compensatory patterns. The inline lunge chop and lift test on a dynamometer is one technique that has been identified as a reliable and valid measure of rotational power involving the proximal segments and appears to control for compensatory movements [6,10]. The strict upright inline lunge position mandates that participants maintain hip and trunk alignment and control while forcefully rotating the trunk and arms [6,8]. It has been proposed that the incremental stability and mobility required to perform the movement is more sport specific and capitalizes on the static stability of the deep proximal musculature while integrating the rotational power of the superficial musculature [3,8]. However, measures using a dynamometer requires expensive and uncommon equipment. It seems reasonable that combining the inlinePalmer TG (2017) Inter-day session reliability of a novel assessment for rotational power of the pelvis, spine and trunk J Spine Care, 2017 doi: 10.15761/JSC.1000111 Volume 1(2): 2-5 lunge position with a ball toss movement will produce a field test that can assess inter-session reliability of rotational power for the proximal segments with good to excellent consistency. Therefore, the purpose of this project was to assess the long-term inter-session reliability of a novel inline lunge ball toss (ILBT) using a randomized control trial study. Based on previous literature we hypothesize that this test would have a limited learning effect and reveal good to excellent inter-session reliability over time.