Gait, or the manner in which humans walk, is one of the basic activities of humans and plays an essential role in maintaining daily life and physical health.¹ It allows individuals to perform their everyday tasks, engage in physical activities, and sustain their well-being.² In recent years, gait analysis has attracted considerable interest in the medical and health sciences because of its clear association with balance, neuromuscular coordination, and overall physical abilities.^3,4

Conventional gait analysis mainly evaluated the average value of the temporal and spatial gait parameters.⁵ Recently, however, the concept of gait variability has been introduced, which is a more precise way to reflect an individual’s physical condition or ability to control neuromuscular muscles, not just the result of average values.⁶ Gait variability refers to fluctuations in human movement explained by the standard deviation (SD) or coefficient of variation (CV) of the temporal and spatial gait parameters, and the larger the value, the greater the variability.⁷ A higher level of CV typically indicates greater instability and may reflect diminished motor control, balance issues, or underlying health problems. On the other hand, lower CV suggests more stable, consistent walking patterns.⁸ Studies have demonstrated that gait variability is closely associated with various health conditions, including neurological disorders, aging, and particularly musculoskeletal pain.^9,10 Especially, musculoskeletal pain disrupt the rhythm and balance of gait, leading to an increase in gait variability, which in turn reflects compromised physical function.^9,11

In response to these concerns, there has been a growing interest in alternative therapies for pain management. Musculoskeletal pain is a very common problem in modern society, and for pain management and relief, there is an increasing tendency in the medical community to prefer alternative treatments such as traditional medicine, acupuncture, and aromatherapy, which have relatively few side effects.¹² One of these alternative treatments is using a magnet.¹³ Magnetic therapy, in which magnets are applied to the body to relieve pain, is believed to work by promoting muscle relaxation and enhancing blood circulation.¹³ Furthermore, it is relatively safe, durable, noninvasive, and easily obtained from pharmacies or some supermarkets.^13,14 Such magnetic therapy has been used in various objects, such as wristbands, necklaces, bracelets, backbands, and mats, and forms a large-scale industry by promoting sedation and pain relief effects of body parts.^15-17 Thus, Advocates of this therapy suggest that magnets may impact the body’s electromagnetic field, potentially reducing pain, enhancing cellular function, and assisting in tissue repair.

Despite the increasing use of magnets for pain relief, research on their effectiveness is conflicting. Although several studies have demonstrated the potential benefits of magnetotherapy to relieve pain and improve quality of life, there is still disagreement in the scientific community about the exact mechanisms by which magnets exert these effects^18,19, and no studies have reported the effects of magnets on gait variability. Therefore, this study aims to determine whether self-therapy with a magnetic pain relief patch (MPRP) effectively improves gait variability and provides a new treatment paradigm. Therefore, this study aimed to evaluate the effectiveness of self-pain relief patches on gait variability in adults to broaden the understanding of pain management and determine whether they can help develop future treatment strategies.

1. Participants

The study participants consisted of 10 healthy men and women in their 20s living in Gyeongsangbuk-do. The criteria for exclusion were as follows: (1) those who had restricted walking due to a history of lower extremities or injuries during the past 6 months, (2) those who found it difficult for researchers to participate due to physical or mental problems, and (3) those who participated in other exercise programs were excluded. The study purpose and experimental content were explained to all participants in advance, and voluntary consent was obtained. Table 1 shows the demographic information of the participants.

Table 1

General characteristics of participants

Characteristics	n=10
Age (years)	24.8±3.4
Sex (male/female)	6/4
Weight (kg)	71.4±22.5
Height (cm)	176.6±10.8

Data are presented as mean±standard deviation.

2. Measurements tools

1) Gait measurement

An accelerometer sensor (inertial measurement units, IMUs, Gait Up, and Switzerland) was used for gait measurement in this study. The Gait Up device, using IMU sensors, shows high reliability and accuracy in measuring gait parameters, with intraclass correlation coefficients values above 0.958.20 The spatiotemporal gait parameters collected from the accelerometer sensor were ground contact time, cadence, stance phase, swing phase, double support, stride length, and swing width, and were analyzed as gait variability. Gait variability was calculated as a coefficient of variation (CV)=[stand deviation/mean] ×100.

The gait variable was defined as follows: (1) gait cycle time (s), the time elapsed between the first contact of a foot and the first following contact of the same foot; (2) cadence (s/m), the number of steps a person takes in 1 minute; (3) stance phase (%), the rate at which one foot supports the ground in the gait cycle; (4) swing phase (%), the rate at which one foot does not touch the ground in the gait cycle; (5) double support (%), the percentage of both feet supporting the ground; (6) stride length (m), the distance covered between the spot where one foot hits the ground and the next time that same foot hits the ground again; and (7) swing width (m), the maximum lateral deviation of the foot from the swing.

2) Magnetic pain relief patch

MPRP was attached to nine muscles trigger points on both lower extremities, including the biceps femoris, gastrocnemius medialis, gastrocnemius lateralis, rectus femoris, soleus, semitendinosus, tibialis anterior, vastus medialis, and vastus lateralis (Figure 1).

Fig. 1. An example of magnetic pain relief patch.

3. Intervention

The study participants attached the MPRP to 18 muscles of both lower extremities for 24 hours. A 6-minute walking test was performed before attaching MPRP. The post-test was measured after attaching MPRP for 24 hours and with it removed. The participant first wore the accelerometer sensor on both feet and then walked for >6 minutes for a roundtrip distance of 60m on a straight course based on the researcher’s starting signal. After completing the experiment, spatiotemporal walking parameters were collected and analyzed using Excel. During the data analysis process, the initial three strides were removed. Figure 2 shows the examples of the measured accelerometer sensor and the collected data.

Fig. 2. An example of gait variability measured over 300 strides wearing an IMU sensor.

4. Statistical analysis

The data collected in this study were analyzed using the Statistical Packages for Social Sciences (ver 23.0 for Windows) program (SPSS, IBM Corp., Armonk, NY, USA). The general characteristics of study participants were presented as means and standard deviations as descriptive statistics. The Wilcoxon signed-rank test was used to compare before and after the attachment of the MPRP. The significance level α was set to 0.05.

Table 1 shows the general characteristics of the study participants consisting of six males and four females, with the average age, weight, and height of 24.8±3.4 years, 71.4±22.5kg, and 176.6±10.8cm, respectively.

The results of the gait analysis are presented in Table 2. Significant differences were found in gait cycle time, cadence, and double-support CV before and after the attachment of the MPRP (p<0.05).

Table 2

Comparison results pre- and post-experimental intervention

Variables		Pre	Post	p	Effect size
Gait cycle time CV (%)	Left	3.13± 0.49	2.63± 0.67	0.047*	0.629
	Right	3.00± 0.47	2.34± 0.613	0.028*	0.693
Cadence CV (%)	Left	3.11± 0.49	2.61± 0.67	0.047*	0.629
	Right	2.96± 0.45	2.33± 0.62	0.047*	0.629
Stance CV (%)	Left	2.61± 1.22	1.99± 0.45	0.333	0.306
	Right	2.19± 0.43	1.88± 0.49	0.074	0.564
Swing CV (%)	Left	3.98± 1.53	3.30± 0.88	0.241	0.371
	Right	3.53± 0.75	3.10± 0.84	0.139	0.467
Double support CV (%)	Left	10.95± 4.66	7.93± 1.65	0.028*	0.693
	Right	10.95± 4.66	7.93± 1.65	0.028*	0.693
Stride length CV (%)	Left	3.33± 0.27	3.51± 0.71	0.386	0.274
	Right	3.27± 0.37	3.52± 0.70	0.386	0.274
Swing width CV (%)	Left	42.86± 18.92	44.30± 40.23	0.508	0.210
	Right	32.38± 10.47	38.41± 17.39	0.285	0.338

Data are presented as mean±standard deviation. CV: coefficient of variation. *p<0.05.

This study investigated how MPRP affects gait variability in healthy adults. The results of this study revealed that MPRP had a significant positive effect on gait ability. By applying the 24-hours MPRP, the gait cycle time, cadence, and double-support CV parameters were significantly improved. These findings indicate that self-treatment using MPRP can improve kinematic functions, such as walking even in participants without underlying pain or mobility impairment.

Furthermore, gait cycle time CV and cadence CV were significantly improved pre- and post-intervention, suggesting a more dynamic and regular gait pattern. This result may be because magnetotherapy affects muscle activity and regulation by stimulating neurons.¹⁶ The magnetic field affects ion channel activity and nerve conduction, thereby improving the regulation and timing of muscles.^21,22 Therefore, this enhancement may be a potential stimulating effect of magnetic stimulation therapy on muscle activation and reactivity. Moreover, it is possible that the stimulation of MPRP improved the coordination of the nervous system, allowing the subject to maintain a more constant and faster gait pattern.^21,22 Therefore, these results suggest that MPRP may be useful for improving gait function in sports and fitness environments.

Double-support CV is a parameter that can evaluate the stability or consistency of gait, and the lower its value, the higher the stability and consistency of gait.²³ In this study, the application of MPRP resulted in a significant reduction in double-support CV. This suggests that MPRP may contribute to improving gait stability. Magnetic stimulation prevents muscle atrophy, induces muscle hypertrophy, and enhances muscle metabolism and turnover rate, thereby optimizing muscle function.²⁴ Improved muscle function reduces instability during gait, enhances coordination, and maintains a stable gait pattern, which likely led to the observed reduction in double support CV.

On the other hand, the present study did not find significant differences for stance, swing, stride length, and swing width CV. Both stance and swing CV are associated with gait stability and gait speed²⁵; however, unlike the significant changes observed in cadence and double-support CV, these two components may require more complex interactions for the effects of the MPRP to be manifested. While cadence and double support can be considered immediate indicators of gait stability, stance and swing are influenced not only by stability but also by multiple factors such as fatigue and other physiological elements.²⁶ Therefore, while MPRP may have improved short-term stability, it might not have provided a strong enough mechanism to affect stance and swing. This suggests that more long-term studies are needed to better understand the potential effects. The lack of significant differences in stride length and swing width CV may indicate that MPRP has relatively limited effectiveness on the spatial aspects of gait. These factors, including stride length and swing width, are influenced by physical elements such as muscle strength and joint mobility, and it is unlikely that simple sensory stimulation alone would lead to substantial changes.²⁷

Although the mechanism underlying the effects of MPRP on gait improvement is still unclear, this study presented the results of noninvasive interventions for pain management in the context of improving gait stability and efficiency. This provides a practical solution that can complement existing pain management and rehabilitation strategies with a noninvasive and easily applicable intervention method. However, this study has some limitations. First, this study has a relatively small sample size, and since it only observed the short-term effects of the MPRP, the generalizability of the findings is limited. Therefore, future research should focus on longer-term application of MPRP and involve a larger sample size to validate the results. Second, because this study enrolled healthy adults, the effects of MPRP on patients with musculoskeletal disorders or gait problems remain unknown. Therefore, whether the risk of falls, an important problem in these populations, can be potentially reduced should be evaluated by investigating the effects of applying MPRP to subjects with chronic musculoskeletal pain such as the elderly or those with osteoarthritis in the future. Third, this study is a single-group design without a control group, and since the effects of the MPRP were not compared with other treatment methods, independent validation of the results may be difficult. Therefore, future research should include a control group to enable more robust experimental comparisons. Despite these limitations, this study is the first to reveal the effect of MPRP on gait variability and is significant in understanding pain management and developing future treatment strategies.

In conclusion, MPRP significantly affects gait cycle time, cadence, and double support CV in healthy adults. This study suggests that MPRP may improve gait variability and has potential as a supplementary noninvasive intervention for pain management and rehabilitation. However, further validation through larger and more diverse populations is necessary to confirm these findings.