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Kikuchi et al. | Journal of Clinical and Translational Research 2024; 10(2): 172-179 173
and the lumbar spine range of motion (ROM) [8]. Nonetheless, average height: 170.3 ± 4.3 cm; and average weight: 70.5 ± 13.3 kg).
the causative factors (e.g., physical and functional) of LBP should Participants were excluded if no consent was provided, if they had
be considered during the treatment process. a history of LBP within the past 2 years, or could not perform
LBP is commonly treated with conservative management, the self-SNAG exercise. The study was a prospective randomized
which includes management exercise and manual therapy [14]. double-blinded crossover controlled study investigating the effect
Among the different forms of manual therapy, mobilization with of self-SNAGs on lumbar spine ROM in asymptomatic college
movement (MWM), devised by New Zealand physiotherapist students.
Brian Mulligan [15,16], could effectively reduce pain and
increase ROM at the affected joints of patients. A sustained 2.2. Protocol
natural apophyseal glide (SNAG) is an MWM technique that Each participant performed a warm-up, consisting of lumbar
encourages the patient to move in a painful restricted direction. flexion, extension, lateral bending, and rotation movements
At the same time, the therapist applies a specific force to the spine that were performed 3 times in each movement direction. In
through the spinous process in a direction parallel to the facet joint this crossover study, different exercises were performed in
plane [17-26]. The applied force could subsequently eliminate pain Phases I and II. The envelope method was used to randomly
during movement, and the pressure on the spinous process should allocate participants to either group A or B. In Phase I,
be adjusted according to the patient’s symptomatic response to the Group A performed self-SNAG, while Group B performed the
SNAG procedure to encourage more movements. This process is conventional trunk flexion. In the self-SNAG group (Group A),
typically performed in three sets for 6–10 times [15,16]. a specifically designed mobilization strap was hooked under the
Following a SNAG procedure, the patient is prescribed a self- spinous process of the L4 lumbar with applied force in the cranial
SNAG as a home exercise to maintain or improve the pain-free direction using both arms. While this force was maintained, the
ROM. A self-SNAG is essentially the same as the conventional subject moved into trunk flexion as far as possible in the absence
SNAG technique, but it is performed solely by the patient. The of pain (Figure 1A). The sham group performed repeated
manual force is applied to the spine by placing a thin strap under trunks forward as far as possible in the absence of pain without
the spinous process of the affected area and applying cranial the strap (Figure 1B). The elbow and knee joints were flexed
inclined pressure through the strap along the plane of the facet during the procedure. Both groups of subjects returned to their
joint. With the force maintained by the strap, the patient repeats starting position immediately after flexing the lumbar spine. The
the active lumbar spine movement. exercises were performed in three sets 6 times/day over 1 week.
Previous studies have examined the effects of lumbar SNAGs The participants were requested to record the time of exercises
in people with and without LBP with varying results [19,20,22]. on a specific table provided to them to evaluate the compliance
Studies have been conducted to compare the effectiveness rate. In Phase II, the exercises in Phase I were crossed over so
of manual therapy interventions on ROM in asymptomatic that Group A performed the conventional trunk flexion while
participants [27,28]. While SNAGs have reportedly improved Group B performed the self-SNAG. The frequency of warm-ups
ROM and flexibility [21], the effectiveness of self-SNAGs has not and exercises and the evaluations were performed similarly to
been reported, warranting further investigations in this regard. Phase I. The participants were instructed to record each exercise
Herein, we evaluated the effectiveness of self-SNAGs in on a designated form daily for 1 week.
healthy subjects based on their lumbar ROM and lower body
flexibility. The purpose of this study was to compare the short- A B
term effectiveness of lumbar self-SNAG with conventional trunk
flexion in asymptomatic college students in terms of lumbar
ROM and hip flexibility. We hypothesized that self-SNAGs
could effectively increase patient compliance and subsequent
improvements in LBP.
2. Methods

2.1. Participants
This study was registered in the University Medical Information
Network (UMIN) Clinical Trials Registry (UMIN000040313).
This study was approved by the ethics committee at the Saitama
Medical University (929) and conducted in accordance with
the Declaration of Helsinki. All participants agreed to sign an Figure 1. Exercises performed in the study. (A) In the self-sustained
informed consent form. natural apophyseal glides group, the participants hooked a strap to the
Participants were recruited by means of advertising using L4 spinous process and performed forward trunk flexion. (B) In the
posters placed across Saitama Medical University. We included 14 sham group, participants performed repeated forward trunk flexion
participants for the present study (average age: 21.0 ± 0.8 years; without the strap.
DOI: https://doi.org/10.36922/jctr.23.00091