Flexibility Measurement Affecting the Reduction Pattern of Back Muscle Activation during Trunk Flexion

Numerous studies have been conducted on lower back injury caused by deeper stooped posture, which is associated with the back muscle flexion–relaxation phenomenon (FRP). Individual flexibility also affects FRP; individuals with high flexibility have the benefit of delayed FRP occurrence. This study attempted to determine the most efficient measurement of flexibility for evaluating the occurrence and degree of FRP when participants flexed their trunk forward. We recruited 40 male university students who were grouped on the basis of three flexibility measurements (toe-touch test, TTT; sit-and-reach test, SRT; modified Schober’s test, MST) into three levels (high, middle and low). Muscle activation (thoracic and lumbar erector spinae, TES and LES, respectively; hamstring, HMS) and lumbosacral angle (LSA) were recorded when the trunk flexed forward from 0° (upright) to 15°, 30°, 45°, 60°, 75° and 90°. The results indicated that trunk angle had a significant effect on three muscle activation levels and LSA. The effects of muscles and LSA varied depending on flexibility measurement. TTT significantly discriminated LES electromyography findings between high and low flexibility groups, whereas MST and SRT distinguished between high and non-high flexibility groups. The TTT values positively correlated with the time of LES FRP occurrence, showing that the higher the TTT, the slower the occurrence of FRP. This is beneficial in delaying or avoiding excessive loading on the passive tissue of the lumbar spine when performing a deeper trunk flexion.

A quantitative approach for measuring the degree of flexibility of business process models

Purpose The purpose of this paper is to measure the flexibility of business process models. The authors give the notions of flexible process distance, which corresponds to the number of change operations needed for transforming one process model into another, considering the different perspectives (functional, operational, behavioral, informational, and organizational). Design/methodology/approach The proposed approach is a quantitative-based approach to measure the flexibility of business process models. In this context, the authors presented a method to compute the distance between two process models. The authors measured the distance between a process model and a process variant in terms of the number of high-level change operations (e.g. to insert or delete actors) needed to transform the process model into the respective variant when a change occurred, considering the different perspectives and the flexible features. Findings To evaluate the flexibility-measurement approach, the authors performed a comprehensive simulation using an emergency care (EC) business process model and its variants. The authors used a real-world EC process and illustrated the possible changes faced in the emergency department (possible variants). Simulation results were promising because they fit the flexibility needs of the EC process users. This was validated using the authors’ previous work which consists in a guidance approach for business process flexibility. Research limitations/implications The authors defined six different distances between business process models, which are summarized in the definition of total process distance. However, changes in one perspective may lead to changes in other perspectives. For instance, adding a new activity may lead to adding a new actor. Practical implications The results of this study would help companies to obtain important information about their processes and to compare the desired level of flexibility with their actual process flexibility. Originality/value This study is probably the first flexibility-measurement approach which incorporates features for capturing changes affecting the functional, operational, informational, organizational, and behavioral perspectives as well as elements related to approaches enhancing flexibility.

Accurate nanoscale flexibility measurement of DNA and DNA–protein complexes by atomic force microscopy in liquid

We obtain accurate three-dimensional persistence length measurements for DNA and DNA–protein complexes using liquid AFM imaging, validated by optical tweezers.