Effects of Manual Therapy on Fascial Distortion Model in Adolescent Ankle Sprain: A Pilot Study

Abstract

Objectives

The present study aimed to assess the feasibility of investigating the effects of manual therapy on ankle functional muscle strength, static balance, and disability in adolescent patients with an ankle sprain.

Methods

The study was a nonrandomized prepost clinical feasibility trial. From September 2021 to February 2022, 31 patients with ankle sprain received manual therapy. Functional muscle strength of plantar flexor muscles and static balance were evaluated using the standing heel-rise and unipedal stance tests on the injured and healthy legs before and after the first and second sessions. Foot and Ankle Disability Index (FADI) assessed the disability at baseline, after the first and second sessions, in the third and sixth weeks.

Results

Within-group analysis of the unipedal stance test with open and closed eyes and the standing heel-rise test showed that injured legs significantly improved after the first and second sessions, compared to uninjured legs (P < .05). Furthermore, there were significant differences among all repeated FADI measures (P < .05).

Conclusions

This study demonstrated that a study was feasible to measure ankle functional muscle strength, static balance, and disability in adolescent patients with an ankle sprain.

Introduction

Ankle sprain is one of the most frequent musculoskeletal injuries affecting the lower extremity in physically active people.¹ It is characterized by stretching, partial, or complete tearing of one or more ligaments around the ankle joint as a result of an unintentional twisting motion that exceeds the normal range of motion of the joint.² The anterior talofibular ligament (ATFL) and calcaneofibular ligament are most frequently injured in ankle sprains. Mechanism of injury, foot posture, rotational stress on the joint and stabilizing ligamentous structures all affect the severity of an ankle sprain.³ The incidence of ankle sprain based on ATFL injuries ranged from 3.2% to 80%, according to Rougereau et al.⁴

In addition to traditional treatment approaches for an ankle sprain, such as exercise therapy, taping/bracing, electrophysical agents, surgery, and acupuncture,¹ manual therapy is becoming increasingly popular.^1,5,6 Some manual therapy approaches aid in improving the ankle range of motion, pain relief, dynamic balance, and function at ankle sprains.^5,6

Manual therapy aims to improve clinical features, disability, quality of life, and healthcare costs of ankle sprain patients. A modern manual therapy approach is the Fascial Distortion Model (FDM), developed by the American physician Stephen Typaldos in 1991, which suggested that musculoskeletal disorders result from distortions in the fascia.⁷ FDM is a holistic, patient-centered, and specific manual therapy method with specific pathology definitions based on the patient's body language, hand gestures, quality of pain, basic objective movement tests, history, and mechanism of injury. Thus, the intervention is based on patient presentation and appropriate intervention strategy based on FDM. There are 6 different fascial distortion types proposed in this model. The techniques are also named likewise: trigger band, herniated trigger point, folding distortion, continuum distortion, tectonic fixation, and cylinder distortion. To help relieve pain and eliminate dysfunctions, FDM-based manual therapy techniques vary from 1 distortion type to another. These types are: intense manual pressure on specific points or along physical lines, distraction or compression on the joints, superficial stroking to the closest layer of connective tissue to the surface, or gentle stretching of the muscles around the joint. The present study aimed to assess the feasibility of investigating the effects of FDM-based manual therapy on ankle functional muscle strength, static balance, and disability in adolescent patients with an ankle sprain.

Methods

Design

The study design was a nonrandomized prepost feasibility study.

Ethics

The present study followed the Declaration of Helsinki on medical protocol and ethics, and ethical approval was obtained from the regional Ethical Review Board of the University of Pecs (Approval Number: 9004-PTE2021). In addition, informed assent and consent forms were obtained from the adolescents who participated in the present study and their parents, respectively.

Participants

Thirty-one patients participated in the study. Based on Post hoc power analysis with 99% achieved power and 5% type I error using the G* Power software (G* Power, Ver. 3.1.9.6, Heinrich Heine University Düsseldorf, Düsseldorf, Germany), effect sizes were respectively as d = 0.95, d = 0.96, and d = 2.01 for the endurance of the ankle plantar flexor musculature, eyes open static balance and disability, comparing the measurement after the second session with the baseline.⁸

This research was conducted at the Department of Paediatrics of the Division of Paediatric Surgery of Medical School of the University of Pécs between September 2021 and February 2022. Based on the patient's medical history, physical examination, and radiographic imaging, a pediatric orthopedic surgeon diagnosed the patient with an ankle sprain. Consecutive patients aged between 8 and 18 years with acute (<1 week) ankle sprains presenting to the department were recruited into the study. Patients with any type of ankle sprain in the previous week and between 8 and 18 years old were included. Exclusion criteria were lower extremity-related fractures, subacute and chronic ankle sprain, contagious infection, severe cardiovascular disease, deep vein thrombosis, phlebitis, inflammatory arthritis, malignancy, bone disease, congenitally deformed bone, vertebral artery insufficiency, recent operative procedures, and withdrawal of informed consents/assents. Different authors were responsible for admitting patients, delivering the intervention, and obtaining measurements.

Procedure

An author who was trained according to European Fascial Distortion Model Association regulations provided the treatments. Fifteen-minute treatment sessions were twice a week for 4 weeks. The intervention processes applied to patients varied depending on their clinical presentation (Table 1). Possible side effects of the procedure were pain during treatment, erythema, soreness, tenderness, bruising, and hemorrhagic petechiae. The following techniques utilized:

• ■Trigger band technique: The practitioner presses down on the trigger band's length using their thumb's edge to untwist the twisted fascial fibers. The other hand modulates the tension on the skin, preventing the tissue in front of the treating thumb from bunching up.
• ■Herniated trigger point technique: Intense and continuous compression is applied to trigger points in the herniated myofascial tissue.⁹ The herniated tissue is reduced back below the tissue plane into which it has protruded by the practitioner using their thumb. When reducing the herniated trigger point, pressure should be administered initially with a progressive increase until tissue tension is maximized.
• ■Continuum technique: Precise, firm, and brief compression is applied to the continuum distortion. Once the precise force direction is attained, compression on the bone-to-soft tissue transition zone is raised and held until a sharp change occurs.
• ■Folding technique: It can be applied to the affected joint as distraction or compression and should be painless. It is applied to the affected joint in many directions. To assist in untorque the distorted fascia, a minor twisting motion should be performed while it is maintained.
• ■Cylinder technique: It can be applied to the affected limb as traction or compression and should be painless Hands are wrapped around the proximal or distal section of the limb. While maintaining steady squeezing pressure, hands move along the limb to untangle the fascia. In the compression variant, hands move closer together after holding the limb with 1 hand proximally and the other distally.
• ■Tectonic technique: The extremity distal or proximal to the affected joint is grasped and slowly pumped by alternately distraction or compression. High-velocity, low-amplitude thrust can also be utilized.

Table 1.

Characteristics of Participants and Intervention Properties

Variables	n (%) Mean ± SD Median (min; max)
Sex
Female	12 (39)
Male	19 (61)
Age (years)	14.5 ± 2.22 15 (8; 18)
Affected side
Right	21 (67.7)
Left	10 (32.3)
Doing sports
Additional sport	23 (74.2)
Only compulsory physical education	8 (25.8)
Passed time after injury (day)	3.10 ± 2.21 2 (0; 7)
Interval between 2 sessions (day)	4.00 ± 1.97 4 (1; 10)
Total sessions (number)	3.26 ± 1.48 3 (2; 8)
First session duration (minute)	12.9 ± 2.99 13 (5; 20)
Second session duration (minute)	12.2 ± 4.40 12 (2; 23)

BMI, body mass index; min; max, minimum; maximum; SD, standard deviation.

Outcome Measures

The patients were followed for 6 weeks. The standing heel-rise test and the unipedal stance test were performed just before and after first and second session. Foot and Ankle Disability Index scores were taken just before and after first session, after second session, in the third and sixth weeks of follow-up.

• ■Standing Heel-Rise Test: It is a valid and reliable functional test to measure the endurance of the ankle plantar flexor musculature.^10,11 The patient was asked to stand facing the wall (or evaluators), lift 1 leg, and raise the heel on the tip of the toe continuously, approximately every 2 seconds. The patient could lean on the wall with 1 finger, but only for balance. Patients executed as many repetitions as possible until they could not complete the test. The test ended at the following conditions: (1) leaning against the wall (or pushing the person in front), (2) bending the knee, (3) compared to the initial range of motion, decrease by more than 50% at the range of motion of ankle plantar flexion, (4) losing balance and stepping out, (5) demanding for a halt, or (6) achieving 25 heel-rise repetitions. For this study we used a set of 25 heel-rise repetitions as a benchmark of normal.¹² The test was conducted on the injured and healthy legs before and after the first and second FDM sessions.
• ■Unipedal Stance Test: It is a valid method for determining static balance ability and stability.¹³ Reduced test time is an indicator of decreasing balance. Minimal detectable change varied from 5.5 and 16 seconds.¹⁴ Patients were asked to stand barefoot on their chosen lower extremity while the other was raised so that the supported limb was close to the ankle but not touching. All patients were instructed to gaze at a spot on the wall in front of them at eye height and to cross their arms over their chests before lifting their feet during testing with their eyes open. A stopwatch was used to measure how long the patient can stand on the chosen lower extremity. It commenced when the patient lifted his/her foot off the floor. The test ended at the following conditions: (1) using the arm (ie, moving the crossed arms), (2) using the raised leg (moving toward or away from the standing limb or touching the floor), (3) moving the weight-bearing leg to maintain balance (eg, rotated leg on the ground), (4) elapsing a maximum of 45 seconds, or (5) opening eyes when performing the eyes closed test. The test was conducted on the injured and healthy legs, with the eyes open and closed before and after the first and second sessions. The best and the mean scores were documented on the data collection sheet after completion of the test 3 times with both eyes open and closed. A set was made up of an eye-open trial and an eye-closed trial. Five-minute breaks can be allowed between test sets if the patients require them. The test was conducted on the injured and healthy legs before and after the first and second FDM sessions (Fig 1).
• ■Foot and Ankle Disability Index (FADI): It is a valid, reliable, and self-reported questionnaire to assess disability related to foot and ankle disorders.¹⁵ The FADI consists of 34 items and 3 categories, of which 22 items are for activity, 4 for pain, and 8 for sports-related function. FADI has subscales as FADI and FADI Sport. A maximum total score of 104 points for FADI and 32 points for FADI Sport is possible based on a 5-point Likert scale (from 0 to 4). A lower score reflects a more severe disability. The score can be expressed as a percentage and ranges from 0% to 100% overall or per component.¹⁶ Minimal clinically important differences for FADI and FADI Sport were 4.5 points and 6.4 points, respectively.¹⁷ At baseline, after the first and second FDM sessions, also in the third and sixth weeks of follow-up, FADI scores were taken.

Fig 1.

The unipedal stance test.

Statistical Analysis

Statistical analyses were performed using Microsoft Excel 2016 (Microsoft Corporation, Redmond, Washington) and Jamovi (Version 2.2.5, The Jamovi Project, Sydney, Australia). Statistically significance was determined as P < .05. The Shapiro-Wilk test was used to assess the normal distribution assumption. Median (minimum; maximum) and mean ± standard deviation values were utilized to represent descriptive statistics for numeric variables. In addition, the frequency (n) and percentage values were given for the categorical variables.

To determine the differences between the dependent groups of FADI measurements, paired sample t test and Friedman's test with Durbin-Conover pairwise comparisons were performed after determining whether the variables met the necessary assumptions. Wilcoxon signed-rank test was performed to resolve the differences between the dependent groups of the Standing Heel-Rise Test and Unipedal Stance Test. The effect of an additional sport or sex difference on changes in standing heel raises or FADI changes was analyzed with Mann–Whitney U test. The differences and the relationship between FADI changes were examined with independent samples t test and Pearson Correlation test, respectively. The Pearson Correlation test was also used to explore relationships between patient characteristics and intervention process properties. The following rules were applied to interpret the size of a correlation coefficient: value 0.00-0.29 as negligible correlation, 0.30-0.50 as low, 0.51-0.70 as moderate, 0.71-0.90 as high, and 0.91-1.00 as very high correlation.¹⁸ A prior result was subtracted from a subsequent result to generate a change variable.

Results

Thirty-one participants were included in the study. The baseline characteristics of participants are given in Table 1.

Within-group analysis of the standing heel-rise test revealed that patients' injured legs had significantly improved after the first and second sessions (P = .002 and P = .022, respectively) (Fig 2). Other comparisons also showed significant differences (Table 2).

Fig 2.

Early effects of the first FDM session on the standing heel-rise test.

Table 2.

Within Groups Analysis of the Standing Heel-Rise Test

	Presession		Test Statistics		Postsession		Test Statistics
	Injured Leg	Healthy Leg	W	P	Injured Leg	Healthy Leg	W	P
First session			.00a	< .001a
Mean ± SD	13.0 ± 10.75	25.0 ± .00			16.5 ± 11.49	25.0 ± .00	.00c	.002c
Median (min; max)	14 (0; 25)	25 (25; 25)			25 (0; 25)	25 (25; 25)	.00e	.002e
Second session			.00b	.014b
Mean ± SD	21.1 ± 7.48	25.0 ± .00			21.9 ± 6.66	25.0 ± .00	.00d	.014d
Median (min; max)	25 (0; 25)	25 (25; 25)			25 (0; 25)	25 (25; 25)	.00f	.022f

min; max, minimum; maximum; SD, standard deviation; W: Wilcoxon signed-rank test.

^aComparison between injured and healthy leg before first session.

^bComparison between injured and healthy leg before second session.

^cComparison between injured and healthy leg after first session.

^dComparison between injured and healthy leg after second session.

^ePrepost comparison of injured leg in first session.

^fPrepost comparison of injured leg in second session.

Within-group analysis of the unipedal stance test with open eyes revealed that patients' injured legs had significantly improved after the first and second sessions (P = .003 and P = .047, respectively). Furthermore, the test with closed eyes showed that patients' injured legs had significantly improved after the first and second sessions (P < .001 and P = .007, respectively). Besides, healthy leg comparisons were similar (P > .05) (Table 3).

Table 3.

Within Groups Analysis of the Unipedal Stance Test

	Eyes	Injured Leg		Test Statistics		Healthy Leg		Test Statistics
		Presession	Postsession	W	P	Presession	Postsession	W	P
First session  Mean ± SD  Median (min; max)	Open			16.50	.003a
		22.39 ± 17.8	28.77 ± 18.09			42.94 ± 6.09	42.48 ± 8.39	6.00	.855
		19 (0; 45)	38 (0; 45)			45 (18; 45)	45 (6; 45)
	Closed			36.00	< .001a
		7.47 ± 7.84	13.08 ± 13.9			18.84 ± 12.79	20.98 ± 13.95	148.00	.136
		6 (0; 28.3)	8.33 (0; 43.3)			12.67 (2.67; 45.0)	15.67 (2.33; 45)
Second session  Mean ± SD  Median (min; max)	Open
		35.35 ± 15.25	38.26 ± 14.92	7.50	.047a	42.23 ± 7.45	42.39 ± 8.96	10.00	1.000
		45 (0; 45)	45 (0; 45)			45 (11; 45)	45 (5; 45)
	Closed
		14.33 ± 13.43	16.86 ± 14.26	62.50	.007a	22.57 ± 16.17	22.45 ± 15.78	131.50	.607
		8.67 (0; 45)	11 (0; 45)			16 (2.33; 45)	14.33 (2.33; 45)

min; max, minimum; maximum; SD, standard deviation; W, Wilcoxon signed-rank test.

^aP < .05.

Paired within-groups analysis of FADI indicated that significant improvements were found at all measurement times compared to baseline according to paired sample t test (P < .001) (Fig 3). Friedman's test also showed that there were significant differences among all repeated measures (χ² = 112, P < .001) (Table 4).

Fig 3.

Early effects of the first FDM session on gait.

Table 4.

Paired Within Groups Analysis of the FADI Scores, Comparing to the Baseline

Measuring Times	Mean ± SD Median (min; max)	Test Statistics
		Paired t test (t)	P	Durbin-Conover (t)	P
Baseline	42.9 ± 24.62 44.2 (1.00; 96.2)
First session	70.6 ± 23.42 76.9 (16.3; 99.0)	8.28	< .001	8.34a 10.09b 16.82c 21.13d	< .001
Second session	87.8 ± 18.89 94.2 (18.3; 100)	10.06	< .001	18.44a 6.73c 11.04d	< .001
Third weeks follow-up	96.6 ± 6.27 100.0 (74.0; 100)	12.04	< .001	25.17a 4.31d	< .001
Sixth weeks follow-up	99.4 ± 1.70 100.0 (94.2; 100)	12.88	< .001	29.48a	< .001

min; max, minimum; maximum; SD, standard deviation, t, paired sample t test.

^aComparison with baseline.

^bComparison with second session.

^cComparison with third weeks follow-up.

^dComparison with sixth weeks follow-up.

In the between-group analysis neither additional sports activity nor sex was a significant factor for FADI changes to baseline or changes in standing heel raises for the first and second sessions (P > .05) (Table 5).

Table 5.

Between-Group Analyzes of Both Additional Sports and Sex

	Sport				Sex
Changes	Additional Sports	Only Compulsory Physical Education	Test Statistics		Female	Male	Test Statistics
	Mean ± SD Median (min; max)	Mean ± SD Median (min; max)	Z, t	P	Mean ± SD Median (min; max)	Mean ± SD Median (min; max)	Z	P
FADI: Baseline to first session	30.5 ± 18.1 27.9 (−.9; 62.5)	19.7 ± 18.8 19.3 (0; 53.8)	t = 1.43	.164	27.6 ± 20.6 30.8 (−.9; 56.7)	27.8 ± 17.8 24.1 (0; 62.5)	114.0	1.000
FADI: Baseline to second session	48.2 ± 25.5 47.1 (6.70; 97.1)	35.6 ± 21.5 36.5 (3.80; 63.5)	t = 1.24	.224	48.3 ± 18.5 50.5 (8.70; 74.0)	42.8 ± 28.4 39.4 (3.80; 97.1)	88.0	.301
FADI: Baseline to third week follow-up	57.2 ± 25.2 58.6 (11.5; 99.0)	43.8 ± 22.3 48.5 (3.80; 73.1)	t = 1.34	.191	59.7 ± 15.8 60.6 (30.8; 83.6)	50.0 ± 28.9 47.1 (3.80; 99.0)	87.0	.282
FADI: Baseline to sixth week follow-up	60.6 ± 23.9 66.3 (17.3; 99.0)	44.6 ± 23.1 48.5 (3.80; 73.1)	t = 1.64	.111	62.0 ± 16.4 63.0 (37.5; 84.6)	53.0 ± 28.2 48.1 (3.80; 99.0)	94.5	0.441
SHR: first session	2.70 ± 3.90 0 (0; 11)	5.88 ± 7.41 2 (0; 17)	Z = 74.0	.378	3.75 ± 5.67 0 (0; 17)	3.37 ± 4.86 0 (0; 16)	114.0	1.000
SHR: second session	1.13 ± 2.44 0 (0; 10)	0 ± 0 0 (0; 0)	Z = 64.0	.090	.750 ± 1.54 0 (0; 5)	.895 ± 2.49 0 (0; 10)	109.0	.803

FADI, Foot and ankle index; min; max, minimum; maximum; SD, standard deviation; SHR, standing heel-rise test; t, Paired sample t test; Z, Mann-Whitney U test.

In addition to the above, all FADI changes were correlated with each other (P < .05) and with the interval between 2 sessions (P ≤ .001). The second session duration was weakly correlated with FADI changes to the baseline in the third and sixth weeks (P = .044 and P = .045, respectively). The number of total sessions was also weakly correlated with FADI change to the baseline in the sixth week (P = .039). A moderate negative correlation was incidentally found between the interval between 2 sessions and the second session duration (P = .034). Analysis of some minor variables also showed no correlation between the passed time after injury and FADI changes to the baseline (P > .05). Likewise, age did not correlate with FADI changes to the baseline or changes in standing heel raises for the first or second session (P > .05), and FADI changes to the baseline did not correlate with changes in standing heel raises for the first or second session (P > .05) (Table 6).

Table 6.

Correlation Matrix

	Age		FADI 1		FADI 2		FADI 3		FADI 4		SHR 1		SHR 2		PRP 1		PRP 2		PRP 3		PRP 4		PRP 5
	r	P	r	P	r	P	r	P	r	P	r	P	r	P	r	P	r	P	r	P	r	P	r	P
Age			−.067	.721	.022	.906	.119	.524	.113	.544	−.002	.990	−.177	.341	.077	.680	−.107	.567	.138	.459	−.035	.853	−.015	.938
FADI 1	−.067	.721			.641	< .001	.486	.006	.449	.011	.192	.300	.160	.391	.084	.654	−.451	.011	−.082	.660	.084	.655	.062	.741
FADI 2	.022	.906	.641	< .001			.792	< .001	.728	< .001	.159	.393	.090	.632	.030	.872	−.622	< .001	−.228	.217	.142	.446	.248	.179
FADI 3	.119	.524	.486	.006	.792	< .001			.979	< .001	.093	.617	.065	.727	.058	.758	−.697	< .001	.248	.179	.250	.175	.365	.044
FADI 4	.113	.544	.449	.011	.728	< .001	.979	< .001			.061	.743	.137	.462	.004	.983	−.703	< .001	.372	.039	.294	.108	.363	.045
SHR 1	−.002	.990	.192	.300	.159	.393	.093	.617	.061	.743			−.050	.789	.034	.857	−.356	.049	−.137	.461	.099	.598	.108	.562
SHR 2	−.177	.341	.160	.391	.090	.632	.065	.727	.137	.462	−.050	.789			.277	.131	−.103	.583	.317	.082	.159	.392	−.007	.969
PRP 1	.077	.680	.084	.654	.030	.872	.058	.758	.004	.983	.034	.857	.277	.131			−.330	.070	.124	.505	.041	.825	.289	.115
PRP 2	−.107	.567	−.451	.011	−.622	< .001	−.697	< .001	−.703	< .001	−.356	.049	−.103	.583	−.330	.070			−.206	.267	−.074	.693	−.381	.034
PRP 3	.138	.459	−.082	.660	−.228	.217	.248	.179	.372	.039	−.137	.461	.317	.082	.124	.505	−.206	.267			.207	.264	.222	.230
PRP 4	−.035	.853	.084	.655	.142	.446	.250	.175	.294	.108	.099	.598	.159	.392	.041	.825	−.074	.693	.207	.264			.092	.622
PRP 5	−.015	.938	.062	.741	.248	.179	.365	.044	.363	.045	.108	.562	−.007	.969	.289	.115	−.381	.034	.222	.230	.092	.622

FADI 1, FADI changes from baseline to first session; FADI 2, FADI changes from baseline to second session; FADI 3, FADI changes from baseline to third week follow-up; FADI 4, FADI changes from baseline to sixth week follow-up; SHR 1, Changes in standing heel raises between before and after first session; SHR 2, Changes in standing heel raises between before and after second session; PRP 1, Passed time after injury; PRP 2, Interval between 2 sessions; PRP 3, Total sessions; PRP 4, first session duration; PRP 5, second session duration; r, Pearson correlation coefficient.

Discussion

Adolescents may encounter symptoms with the ankle and its associated structures. It is anticipated that some improvements in functional muscle strength, static balance and stability, and disability may emerge by applying FDM-based manual therapy. A feasibility study was needed before conducting a larger-scale clinical trial on the effects of FDM-based manual therapy. The purpose of the present study was to assess the feasibility of investigating the effects of the FDM-based manual therapy on the ankle functional muscle strength, static balance, and disability in adolescent patients with an ankle sprain. The patients received treatment sessions twice a week for 4 weeks and were followed for 6 weeks. The standing heel-rise test and the unipedal stance test were performed just before and after first and second session. Foot and Ankle Disability Index scores were taken just before and after first session, after second session, in the third and sixth weeks of follow-up. The patients were highly satisfied with FDM-based manual therapy and did not request a change of therapy. Drop-out of patients was minimal. They were due to no need for therapy. No systemic adverse events were encountered, but only erythema, tenderness, and tolerable pain during treatment.

Neurophysiological or mechanical factors can influence patients' muscle endurance and strength. Fascia can affect muscle strength and endurance through these mechanisms. Few studies have investigated the effects of manual therapy on ankle functional muscle strength in ankle injuries. According to Allois et al., Fascial Manipulation, in addition to strength training, can improve isometric muscle strength of the ankle.¹⁹ Furthermore, it has been demonstrated that proprioceptive and strength training combined with Maitland's Mobilization and neural gliding increases the ankle functional muscle strength.²⁰ Another study showed that Maitland's Mobilization, in addition to routine rehabilitation training, had a significant effect on increasing dorsiflexor or inverter muscle strength but did not increase muscle strength of plantar flexors. It was suggested that the intervention was insufficient to increase muscle strength.²¹ Following them, the present study showed that FDM-based manual therapy might significantly improve the ankle functional muscle strength, especially plantar flexors. These improvements following manual therapy may be due to biomechanical changes in the structure of the fascia and the neurophysiological mechanisms of the proprioceptive structures around the ankle.

Different findings observed in the literature review on the impact of manual therapy on static balance and stability. These differences in findings might be the consequence of interventions, evaluation period, or chronicity. Joint mobilization is not anticipated to immediately impact static balance, according to Weerasekara et al.⁶ Hoch et al also reported that 2 weeks of Maitland's Mobilization did not significantly change in single-limb stance postural control.²² Moreover, Mobilization with Movement did not outperform sham in enhancing postural control, according to Tomruk et al.²³ On the other hand, weight-bearing Mobilization with Movement improved self-report instability.²⁴ Besides that, Maitland's Mobilization and Neural Gliding, along with proprioceptive and strengthening training, have been shown to alleviate the instability.²⁰ However, when soft tissue manipulation techniques were investigated, it was found that Fascial Manipulation combined with strength training, like strain counterstrain technique, decreased the instability, and also instrument-assisted soft-tissue mobilization combined with cryotherapy improved balance and proprioception, but Fascial Manipulation alone did not affect postural sway.^19,25, 26, 27 The present study demonstrated that static balance and stability were improved by FDM-based manual therapy, both with open and closed eyes. This improvement may be achieved by inhibiting nociception and facilitating proprioception due to the breakdown of adhesions in the fascia, given the comparatively noticeable impact of soft tissue manipulations on stability relative to mobilization.

According to the few studies in the literature which investigated the effects of manual therapy on ankle disability, both 2 weeks and 4 to 5 sessions of Mobilization with Movement significantly reduced the disability, as opposed to a single session of grade III joint mobilization.28, 29, 30 Furthermore, adding joint manipulation of the ankle and foot joints to the rehabilitation had no significant impact.³¹ Fascial manipulation, on the other hand, has a significant impact, according to Kamani et al.²⁷ Also, the present study demonstrated that FDM-based manual therapy significantly improved the disability in each session over the FADI results. Increases in functional muscle strength and stability could be responsible for this improvement in the disability.

Future Studies

Sample size calculation may be done according to the present study. A larger sample size may be utilized due to that patients may discontinue therapy due to its initial effects. Differences at affected side or doing sports may have an effect. They may be determined as an inclusion/exclusion criterion. Specific distortions may be determined as inclusion criteria to investigate the effect of individual techniques. The repetitions of techniques per session may be determined. Pain intensity may be an outcome since it is the main complaint. Future studies on Hungarian questionnaires are also required to assess various outcomes of patients with ankle injuries.

Limitations

First, a limitation was that the present study did not comparatively evaluate the disability using a control group. Secondly, the sample size was not determined based on a priori power analysis. Thirdly, functional muscle strength was measured only during plantar flexion and was not detected during dorsiflexion, inversion, and eversion. Fourthly, the present study should have investigated the effects of manual therapy on dynamic balance. Last but not least, the effect of FDM techniques were not studied separately, each patient received different techniques, therefore it is unknown what techniques may or may not have contributed to the outcomes.

Conclusion

This feasibility trial demonstrated that conducting a study on the FDM-based manual therapy was feasible in adolescent patients with an ankle sprain. The treatment was well tolerated by patients and drop-out of patients was minimal. The ankle functional muscle strength, static balance, and disability were improved.