Comparing the Scores of The Functional Movement Screen™ in Individuals with Low Back Pain versus Healthy Individuals: A Systematic Review and Meta-Analysis

Khalid M. Alkhathami; Bijad Alqahtani

doi:10.26603/001c.120199

INTRODUCTION

Low back pain (LBP) is a widespread musculoskeletal condition that affects up to 80% of individuals throughout their lifetime.¹ It is considered the most common disorder in gymnastics, football, volleyball, and tennis athletes, accounting for 20% of sports injuries involving the spine.^2,3 LBP is typically categorized as mechanical, rheumatic, infectious, tumoral, or mental, with mechanical LBP being the most common, around 90% of cases.⁴ Various factors may contribute to LBP incidence, including age, smoking, genetics, weight (gain), improper weightlifting, nutritional disorders, decreased flexibility and hydration, acute injuries, chronic stress, and poor physical conditions.^5,6

The evaluation of patients with LBP, including conducting functional evaluations, is crucial in the clinical field.⁷ Several tools are used to assess patients with LBP, such as the Back Pain Functional Score, Oswestry Disability Index (ODI), Numerical Rating Scale (NRS), Pain Self-Efficacy Questionnaire (PSEQ), Patient-specific Functional Scale (PSFS), and the Functional Movement Screen™ (FMS™).⁸

The FMS™ assesses movement patterns and identifies restrictions and compensations. The primary objective of the FMS™ is to evaluate an individual’s ability to perform various movements, including those related to flexibility, range of motion, muscle strength, coordination, balance, and proprioception. It consists of seven component movements; the deep squat, hurdle step, inline lunge, shoulder mobility, active straight leg raise, push-up, and rotational stability movements. Several of these movements are performed bilaterally and when tests are performed bilaterally, the lower of the two scores is used for analysis.The assessment is carried out through standardized verbal instructions and visual inspection. FMS™ scores are assigned based on task performance, including movement conditions with or without pain and symmetry.^9,10 The score for each movement ranges from 0 to 3, with a total cumulative score ranging from 0 to 21 points.^11,12 Lower scores (≤14) on the FMS™ indicate impaired functional movements associated with the potential for a higher risk of injury.¹³

The purpose of this systematic review and meta-analysis is to examine functional movement scores among patients with low back pain (LBP) and healthy subjects with no LBP and review the validity of the FMS™ tool for screening functional movement among LBP patients.

METHODOLOGY

This systematic review complied with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria.¹⁴

The systematic review and meta-analysis were conducted through a thorough literature search of PubMed, Medline, Ovid, Scopus, and Central research databases using the keywords Functional movement screen AND low back pain. Studies published from 2003 to 2023 were screened to select studies that matched the inclusion/ exclusion criteria. Furthermore, selected study references were reviewed manually to identify similar studies. Only studies that compared the FMS™ between patients with chronic LBP and healthy control subjects were incorporated in the meta-analysis.

Inclusion and exclusion criteria

Papers assessing functional movement among adult patients with LBP (>18 years old) with FMS™ and published from 2003 to 2023 were included. Studies published in languages other than English were excluded. Narrative reviews, systematic reviews, consensus reports, case reports, case series, duplicated studies, published before 2003, studies with insufficient data or findings regarding FMS^TM score, studies with irrelevant findings, studies that used other functional movement tools or assessed patients with another type of pain, and studies for which full text was unavailable were also excluded. Only studies that compared the FMS™ between patients with chronic LBP and healthy control subjects were incorporated in the meta-analysis.

Screening and data extraction

First, title and abstract screening was performed by the authors. Relevant full-text papers and evaluated the research for inclusion criteria were examined by one author. After articles were selected for inclusion, data were extracted and entered in a Microsoft Excel spreadsheet. Extracted data included authors, year of publication, objective, study design, sample size, gender, age, intervention, assessment tool, results, and outcome. Further data for the meta-analyses included total FMS™ score, in addition to scores of the seven FMS™ composite tests were extracted from the articles included in this systematic review.

Risk-of-Bias Assessment

The risk of bias in the incorporated papers was evaluated using the Cochrane Risk of Bias 2 (ROB 2) tool. The ROB 2 tool offers a structured, standardized, and flexible approach to assessing the risk of bias in randomized trials and non-randomized studies of interventions.¹⁵ The tool assesses quality based on five major domains: bias arising from the randomization process, bias due to deviations from intended interventions, bias due to missing outcome data, bias in the measurement of the outcome, and bias in the selection of the reported result. Each domain has a set of signaling questions that inform the risk of bias judgment for that domain. Based on the responses to each domain, the options for a domain-level risk-of-bias judgment are ‘Low’, ‘High’, or ‘Unclear’ risk of bias. A total or overall risk of bias score for each article was not determined.

Statistical analysis

Review Manager, version 5.4 (The Cochrane Collaboration, Oxford, England) was used for data entry and analysis. The standard deviation (SD) of the means were estimated from CI limits or standard mean difference (if not provided). The size of the continuous outcomes effect was reported as standard mean difference (SMD), and the precision of effect size was also reported as a 95% confidence interval (CI). DerSimonian and Laird’s random-effects model was used to compute SMD.¹⁶ Cochrane Q tests and Leave one out (I²) statistics were used to evaluate the heterogeneity and inconsistency across the studies. Leave one out meta-analysis was used for sensitivity analysis to recognize that the overall effect (against which heterogeneity is measured) changes each time an influential study is excluded.¹⁷ Statistical significance was set at p < 0.01 for Cochrane Q tests. If a high heterogeneity was detected, a leave-one-out test (removing studies one by one) was performed.

RESULTS

The initial search strategy provided 91 papers, of which 12 were omitted as duplicates. Regarding the remaining 79 articles, 34 were excluded because they did not match the inclusion criteria. Following screening and assessment, 38 additional articles were excluded because they did not match the study’s objective. Seven studies were considered suitable for and included in this systematic review (Figure 1).

Figure 1.Studies involved in this systematic review.

Overview of the included studies

In terms of the seven included papers, all were published between 2016 and 2023 (Table 1). The articles included 272 adult subjects with an age range of 18-65 years old. The study subjects were patients with LBP, and either athletes, or healthy controls without LBP. The study design varied among the articles; one study was a double-blinded randomized clinical trial,¹⁸ one was a reliability and validity study,¹⁹ one was a cross-sectional study,²⁰ and Four were prospective studies.^7,21–23 Some studies included either males or females, and others included both genders. All included studies assessed LBP using the FMS^TM, but one study also used the Numeric Pain Rating Scale (NPRS) and Oswestry Low Back Pain Disability Questionnaire (OSW).¹⁸ Only one study used intervention which included spinal stabilization exercises (SSEs) and general exercises (GEs).¹⁸

Table 1.Characteristics of the included studies

Author, year	Objective	Study design	Sample size	Study subjects	Sex	Age	Intervention	Assessment tool	Results	Outcome
Alkhathami K et al., 2023¹⁸	Assessing SSEs effects on the level of movement performance, pain intensity, and disability among adults with CLBP.	Double-blinded randomized clinical trial.	40	Adults with CLBP	Both males and females	18 to 65 years (39.9 ± 12.5)	SSEs vs. GEs	FMS ^TM, NPRS, and OSW	Over eight weeks, there was a substantial difference in modified FMS ^TM scores between the SSE and GE groups. -The modified FMS ^TM scores of all patients improved significantly between two adjacent time points: from baseline to two weeks (p = 0.011), two weeks to four weeks (p = 0.001), and four weeks to eight weeks (p = 0.008).	The modified FMSTM with a scoring system might effectively assess mobility quality in individuals with LBP.
Alkhathami K et al., 2021¹⁹	It detects the reliability and validity of the FMS™ with a modified scoring system among young adults with and without LBP.	Reliability and validity study	44	LBP and asymptomatic individuals	Both males and females	LBP group: 26.08 ±4.03, and asymptomatic group: 25.33 ±2.99.	Nil	FMS™	The LBP group scored significantly lower than those without LBP (p-value = 0.008).	-It is considered that the FMS ^TM can differentiate between people who have and do not have LBP. For doctors, FMS ^TM might be a helpful test for evaluating movement quality and identifying mobility limits in LBP patients.
Khoshroo F et al., 2021²¹	Comparing females with LBP functional movement patterns with NPDs.	NA	60	Subjects with LBP and NPDs.	Females	LBP: 26.86 ± 2.22 and NPDs: 26.53 ±2.37.	Nil	FMS™	- Significant lower scores in LBPDs compared to NPDs in the FMS ^TM composite score (12.06 vs. 16.43, p-value < 0.001). -There was a negative association between FMS ^TM composite score and LBP intensity (r (60) = –0.724, p < 0.001) and positive with LBP onset (r (60) = 0.277, p = 0.032) during prolonged standing.	-LBPD females, who are at higher risk for developing LBP, had significantly lower functional movement quality patterns compared to NPDs. -The FMS ^TM could predict subjects at risk for LBP development during prolonged standing.
Enoki S et al., 2020²⁰	-Assessing and examining the physical characteristics of pole vaulters with chronic LBP. -Clarifying the association between FMS™ performance with and without chronic LBP.	A cross-sectional study	20	collegiate pole vaulters	Males	19.6 ± 1.1	Nil	FMS™	-In the chronic LBP group, the difference between the passive and active SLR angle (SLR) was substantially greater than in the non-chronic LBP group (p-value 0.05). -Those with persistent LBP were more likely to have an FMS ^TM 14 score.	- The CLPB group was far more likely to have an FMSTM composite score ≤ 14. -It is critical to examine the active straight leg rise (vs. passive only) and basic motions of pole vaulters using the FMS ^TM.
Gonzalez SL et al., 2018²²	Assessing if the FMS™ and impairments can identify rowers at risk for LBP development.	Prospective cohort study	31	Collegiate Athletes	Females	19.7 ± 1.5 years	Nil	FMS™	There were no differences in FMS™ or impairments between the Uninjured and LBP groups. The FMS™ cutoff score was 16 points.	An FMS ^TM score of 16 predicted a small increased risk of LBP development (1.4) compared to individuals with scores over 16. However, the FMS ^TM is not suggested for screening female rowers since the risk ratio was minimal and the 95% confidence interval was broad.
Clay H et al., 201²³	They were determining whether the FMS™ scores predict the incidence of all injuries, such as LBP, among female collegiate rowers during one rowing season.	Prospective cohort study	37	Collegiate rowers	Females only	Figh risk: 19.25 ± 1.17 Low risk: 19.55 ± 1.21	Nil	FMS™	-Subjects detected as a high risk of injury by the FMS™ were more likely to have LBP during the season (p-value =0.036). -Individuals with LBP history were six times more likely to suffer from LBP during the season (p-value=0.027).	-The FMS™ has been estimated to predict injury among athletes. -The FMS™ has indicated a higher likelihood of a subjective report of LBP.
Ko MJ et al., 2016⁷	Comparing the FMS ^TM scores between CLBP patients and healthy control subjects with using the FMS™ as an evaluation tool for examining functional deficits of CLBP in patients.	NA	40	CLBP patients and healthy controls	Both genders	CLBP:42.20 ± 14.66 and control:43.20 ± 14.41 years	Nil	FMS™	- CLBP patients scored significantly lower on total composite scores (10.95 ± 2.2 points) compared with the control group (14.40 ± 1.8 points), p<0.001). -LBP patients had significantly lower scores on deep squat (1.55 ± 0.7 vs. 2.20 ± 0.5 points, p=0.002), hurdle step (1.95 ± 0.4 vs. 2.45 ± 0.5 points, p=0.002), ASLR (1.85 ± 0.7 vs. 2.55 ± 0.8 points, p=0.005), and rotary stability (1.15 ± 0.4 vs. 1.80 ± 0.4 points, p<0.001). -There were no significant differences between CLBP patients and the control group in inline lunge (1.90 ± 0.7 vs. 2.25 ± 0.7 points, p-value= 0.133), shoulder mobility (1.75 ± 0.9 vs. 1.85 ± 0.6 points, p-value= 0.811), and trunk stability push-up (0.95 ± 0.5 vs. 1.30 ± 0.6 points, p-value=0.056).	The deep squat, hurdle step, active straight leg raise, and rotary stability tasks of FMS™ could be recommended as functional assessment tools to assess functional deficits in CLBP patients.

CLBP: Chronic low back pain, GEs: General exercises, LBP: Low back pain, NA: Not available, NPDs: Non-pain developers, NPRS: Numeric Pain Rating Scale, OSW: Oswestry Low Back Pain Disability Questionnaire, SLR: Straight leg raise, SSEs: spinal stabilization exercises.

Overview of Studies’ Risk of Bias

Table 2 shows a representation of the risk of bias assessment.

Table 2.Risk-of-bias summary

Reference	Sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome assessment	Incomplete outcome data	Selective reporting	Other sources of bias
Alkhathami K et al., 2023,¹⁸	+	+	+	+	?	+	+
Alkhathami K et al., 2021¹⁹	+	+	?	?	+	+	?
Khoshroo F et al., 2021²⁰	+	+	?	?	?	+	+
Enoki S et al., 2020²¹	+	+	?	?	?	+	+
Gonzalez SL et al., 2018²²	+	+	-	-	?	+	+
Clay H et al., 2016²³	+	+	?	?	?	+	+
Ko MJ et al., 2016⁷	?	?	-	-	+	+	?

(+) Low risk of bias, (-) High risk of bias, (?) Unclear risk of bias

Regarding sequence generation and allocation concealment, six studies had a low risk of bias and an unclear risk of bias. In blinding of participants and personnel and blinding of outcome assessment, two studies had a high risk of bias, one study had a low risk of bias, and four studies had an unclear risk of bias. Moreover, five studies showed an unclear risk of bias, and two studies had a high risk of bias regarding the incomplete outcome data section. All studies had a high risk of bias in the selective reporting section. However, regarding other sources of bias, five studies had a high risk of bias, while two had an unclear risk of bias. Overall, the included studies should be considered to have low to unclear risk of bias.

Meta-analysis results

FMS total score among LBP patients and control group

The total score of FMS™ among LBP patients and the control group was available in three papers (144 patients).^7,19,21 The analysis revealed that the LBP group had a significantly lower total FMS™ score than the control group by 1.81 (95% CI (-3.02, -0.59), p=0.004). In addition, a significantly high heterogeneity was found (I²= 89%, p<0.001).

Figure 1.Forest plot of FMS™ means and 95% CIs, grouped by LBP and control group.

CI confidence interval, SD standard deviation, LBP low back pain.

Individual FMS^TM movement patterns

Three studies^7,19,21 (144 patients) reported the scores of the seven FMS™ movement patterns between the patients with LBP and the control group. Of note, when tests are performed bilaterally (hurdle step, in line lunge, shoulder mobility, active straight leg raise, trunk stability push up, and rotary stability), the lower of the two scores is used for analysis, resulting in a single score for those tests.

Deep squat score

There was a significant difference between the patients with LBP control group scores with SMD -1.11 (95% CI (-1.59, -0.62), p< 0.00). Low heterogeneity was found (I²= 46%, p= 0.16).

Figure 2.Forest plot of deep squat movement score and 95% CIs, grouped by LBP and control group. CI confidence interval, SD standard deviation, LBP low back pain.

Hurdle step score

The hurdle step mean score was significantly lower in the LBP group when compared to the control group by 1.41 (95% CI (-2.01, -0.81), p< 0.001). High heterogeneity was found (I²= 85%, p<0.001). A leave-one-out test was done, the Alhathaml et al. study was removed, and the heterogeneity became (I²= 45%, p= 0.18).

Figure 3.Forest plot of hurdle steps score and 95% CIs, grouped by LBP and control group.

CI confidence interval, SD standard deviation, LBP low back pain.

Inline lunge score

Regarding the inline lunge score, the patients with LBP had significantly lower scores than the control group, with SMD -0.41 (95% CI (- 0.74, -0.08), p=0.02). No heterogeneity was found (I²= 0%, p= 0.54).

Figure 4.Forest plot of inline lunges score and 95% CIs, grouped by LBP and control group.

CI confidence interval, SD standard deviation, LBP low back pain.

Shoulder mobility score

There was a non-significant difference in the shoulder mobility score among LBP patients and the control group, with SMD -0.39 (95% CI (-1.03, 0.25), p=0.23). Significant heterogeneity was found (I²= 73%, p-value= 0.03). A leave-one-out test was done, the Khohroo et al. study was removed, and the heterogeneity became (I²= 0%, p=0.77), and SMD became -0.06 (95% CI (-0.49, 0.37), p= 0.78).

Figure 5.Forest plot of shoulder mobility score and 95% CIs, grouped by LBP and control group.

CI confidence interval, SD standard deviation, LBP low back pain.

Active straight-leg raise scores

There was a significant difference between the LBP group and the controls, by SMD -0.75 (95% CI (-1.09, -0.41), p< 0.00). Furthermore, no heterogeneity was found (I²= 0%, p= 0.81).

Figure 6.Forest plot of active straight-leg raises score and 95% CIs, grouped by LBP and control group.

CI confidence interval, SD standard deviation, LBP low back pain.

Trunk Stability Push-up score

The LBP patients reported a significantly lower score in trunk stability push-up screening than the control by SMD -1.05 (95% CI (-1.88, -0.21), p=0.01). A significant high heterogeneity was found (I²= 81%, p=0.00). A leave-one-out test was done, the Khohroo et al. study was removed, and the heterogeneity became (I²= 0%, p=1.0), and SMD became -0.62 (95% CI (-1.06, -0.18), p= 0.00).

Figure 7.Forest plot of push-up score and 95% CIs, grouped by LBP and control group.

CI confidence interval, SD standard deviation, LBP low back pain.

Rotatory stability score

Regarding rotatory stability, a significant difference was revealed between the scores of the patients with LBP and the control group with SMD -0.82 (95% CI (-1.56, -0.08), p=0.03). Significant heterogeneity was found (I²= 78%, p=0.01). A leave-one-out test was done, the Ko et al. study was removed, and the heterogeneity became (I²= 53%, p=0.14), and SMD became -0.48 (95% CI (-1.06, 0.09), p= 0.1).

Figure 8.Forest plot of rotatory stability score and 95% CIs, grouped by LBP and control group.

CI confidence interval, SD standard deviation, LBP low back pain.

DISCUSSION

Functional movement proficiency and examining movement patterns could demonstrate the foundation for lifelong physical activity. While the FMS™ is considered a fundamental screening tool for assessing functional movement, previous research has been primarily focused on the application of FMS™ among athletes.²⁴ This is the first systematic review and meta-analysis using the FMS™ to compare the functional movement scores among adult patients with LBP and healthy subjects. In addition, this study reviews the validity of the FMS™ tool for screening the functional movement abilities of LBP patients.

FMS™ total score

The FMS™ is a commonly utilized screening tool for evaluating functional movement, supported by experimental research conducted and synthesized to date. This research encompasses diverse populations, including youth athletes and adults of both sexes.^25,26

According to the screened studies in this systematic review, the mean total score of the FMS™ among LBP patients ranged from 10.95 to 14.1.^7,19,21 The mean FMS™ scores for control groups ranged from 14.40 to 16.2. The meta-analysis found that LBP patients had a significantly lower total FMS™ score than the control group by 1.81 (p-value= 0.004). These findings support the literature and suggest that LBP patients generally exhibit lower functional movement capabilities than individuals without LBP, as evidenced by their lower FMS™ scores, supporting the validity of the screening tool. These lower scores are due to these FMS^TM tasks being accompanied by lower or upper extremity movement, and some patients with LBP have difficulty in properly recruiting certain muscles, such as trunk stability muscles, and often display limited hip joint mobility. This could be reflected in lower scores seen in those with LBP on the deep squat, hurdle step, ASLR, and rotary stability movements.