Objective To explore the immediate,long-term,and delayed effects of spiral stabilizing muscle chain technique compared to static distraction and Proprioceptive Neuromuscular Facilitation(PNF)stretching techniques on the flexibility of hip flexors.Methods Ninety subjects were randomly divided intothree groups of 30 each.Group 1 underwent the static stretching of the hip joint.Group 2 received PNF stretching,and Group 3 participated in SPS training.All participants were measured for hip extension angle to assess hip flexor flexibility before training,immediately after the first training session,at the end of 4 weeks of training,and 2 weeks after training cessation.Results Within-group comparisons showed significant increases in hip extension angles after one training session,after 4 weeks of training,and after 2 weeks of cessation compared to pre-training(P＜0.05).Between-group comparisons indicated no statistically significant differences in hip extension angle improvements among the three groups after one training session,after 4 weeks of training,and after 2 weeks of cessation(P＞0.05).Conclusion SPS training,static stretching,and PNF stretching all demonstrate good immediate,long-term,and delayed effects on improving hip extension angles,with consistent stretching outcomes.

Collagen fibrils and hydroxyapatite might recognize each other at the mesoscale by multiple cooperative interactions due to their intrinsically repetitive structured surfaces, and thus effectively directing the biomineralization, a biological process involving regulating the growth of bones, teeth and other organs. In this work, we developed a simple technique to prepare nanowire arrays of biological macromolecules by reversely using the biomineralization mechanism, with results similar to the hot wall epitaxy, a molecular beam deposition technique under vacuum. With this technique, we successfully cultured 5-10 μg/mL rat tail type I collagen monomer solutions into collagen nanowire arrays on the mica (001) lattice plane along one unique direction across the whole cleavage surface. The atomic force microscope experiments indicated that the nanowires in the arrays became more crowded with higher monomer concentration, but their width and height remained unchanged, about 60.0 nm and 1.5 nm, respectively. The collagen nanowire coating enhanced the hydrophilicity of the mica surface, reducing the contact angle from 25.8° to 9.5°. Based on the characterization results of electron back scattering diffraction and transmission electron microscope, the collagen nanowires were most likely to be oriented along the mica [110] direction, which validated the quasiepitaxial growth mechanism in more details.