A comparison of the range of motion and dynamic stability of the ankle joint of athletes with an ankle sprain as compared to healthy controls: A cross-sectional study

ABSTRACT

Background:

Ankle sprains are the most common lower-leg musculoskeletal injuries, frequently occurring among athletes and other physical activity individuals. The objective of this study was to compare the ankle range of motion and dynamic stability of healthy and injured athletes for their dominant and nondominant legs.

Methods:

A cross-sectional study design was selected to investigate this study with 32 male soccer players with average age: 22.6 ± 3.3 years, weight: 69.6 ± 5.7 kg, height: 176.8 ± 5.32 cm, with a history of a lateral ankle sprain on the dominant leg for the past 2 years. Ankle range of motion was determined using dorsiflexion and plantar flexion by a goniometer. The dynamic stability was determined using the SWAY medical system. An independent t-test was used to study the differences between healthy and injured groups and between dominant and nondominant legs for dynamic stability, dorsiflexion, and plantar flexion range.

Results:

There were higher significant differences for dynamic stability in healthy participants than in injured participants for their dominant (P = 0.001) and nondominant (P = 0.001) legs. There were significant differences in dynamic stability in the dominant and nondominant leg (healthy [P = 0.033] and injured [P = 0.000] participants). The dominant leg shows higher dynamic stability in healthy group, whereas nondominant leg shows higher dynamic stability in the injured group.

Conclusion:

The study found significant differences between the injured and sound legs. The injured dominant and nondominant leg revealed a striking disparity in the ankle range of motion. Therefore, the study demonstrated that ankle sprain causes due to less stability of the ankle joint, which limits ankle movements.

INTRODUCTION

Lower limbs are the most prevalent site of sport-related injuries, with the ankle and knee being the most frequently injured joints.[1] Ankle sprain is among the most common musculoskeletal injuries in the lower limb among physically active individuals. Around 30% of ankle injuries occur during training sessions, with the remaining 70% occurring during competitions, where performance is substantially higher.[2] High rates of ankle injury occurrence indicate that ankle injuries can be costly to healthcare systems. Ankle injuries cost USD 6.2 billion in high school athletes in the United States and Europe and 208 million in the Netherlands.[3,4] Ankle injuries are more prevalent in females, children, and athletes participating in court sports and indoor games.[5] According to the American Academy of Orthopedic Surgeons, foot and ankle injuries account for 25% of all athletic injuries. Athletes participating in sports demanding jumping and running are more likely to be injured. Sports like athletics, basketball, soccer, football, dancing, and martial arts are associated with frequent foot and ankle injuries.[6] The highest incidence rates are 41.1% in basketball, 9.3% in American football (Rugby), and 7.9% in soccer.[7,8] Each day, almost 5.23 ankle sprains occur per 10,000 athletes, and 9.35 ankle sprains occur during the competition.[9,10] About 9.8% of professional players with a history of an ankle sprain will suffer the same injury in 1 year more than those without a sprain history.[11] Attenborough et al. find that 61% of professional players with ankle joint injuries suffer from a recurrence of the injury.[12] Reduced dorsiflexion range of motion has been identified as a strong predictor of a reoccurrence of ankle sprain.[13]

The magnitude of available ankle range of motion plays a key role in the cause of lower extremity injuries. A sprained ankle is the most common cause of loss of range of motion.[14] A normal range of motion loss is usually observed at the talocrural joint after an ankle sprain.[15] Ankle sprain can be the underlying cause of limitation, as it is characterized by the inability to flex the ankle joint fully, which directly affects the ankle joint range of motion. Tightness in the plantar flexor muscle also limits the range of motion at the ankle joint. Leanderson et al. demonstrated that basketball players’ dorsiflexion range of motion was significantly lower than a group of physically active participants with no history of ankle sprain.[16] Inadequate ankle dorsiflexion restoration demonstrates deficits in ankle dorsiflexion range of motion and stability, which may contribute to the high risk of recurrent ankle sprains.[17,18] Basnett et al. find that the ankle dorsiflexion range of motion (ROM) can affect dynamic stability if it is affected by an ankle injury.[19]

Stability is defined as the ability of the body to retain a center of mass within the limits of the base of support.[20] A study shows a strong relationship between the stability of the ankle joint and range of motion, and ankle stability can be significantly affected when following a good stability program.[21] Along with upper body movements, stability provides crucial information for the ankle joint to adjust its position to help athletes in most specific sports tasks.[22] The injury rate is almost four times higher in athletes with poor stability than in those with normal stability levels.[23] The relationship between stability and ankle sprain injury is inverse, i.e., increasing the stability level will decrease the chance of ankle sprain injury.[24]

Loss of ankle range of motion, especially dorsiflexion range of motion, and stability deficit are some risk factors for the recurrence of ankle injuries in the sports population. Therefore, assessing the ankle joint’s range of motion and stability is important for implementing preventive strategies.[25] Therefore, this study aimed to determine the ankle range of motion and dynamic stability differences between healthy and injured participants. It was hypothesized that healthy and injured participants showed significant differences in ankle range of motion and dynamic stability.

METHODS

Study design and setting

A cross-sectional study was selected to investigate the ankle range of motion and dynamic stability differences in healthy and injured athletes. This study was conducted in the laboratory of the Physical Therapy Department at Imam Abdulrahman Bin Faisal University, Dammam. The study was approved by the local institutional ethics committee, written informed consent was taken from each study participant before study enrollment, and the manuscript adheres to the STROBE guideline.

Participants

Thirty-two male professional soccer players with an average age of 22.6 ± 3.3 years; weight: 69.6 ± 5.7 kg; height: 176.8 ± 5.32 cm, with a history of a lateral ankle sprain on the dominant leg for the past 2 years and 32 age-matched healthy controls (professional soccer players) were selected. Participants with any musculoskeletal or stability-related issues and systemic diseases which may affect the data collection were excluded from the study.[26]

Outcome measures

Ankle range of motion

Ankle range of motion was determined using a manual goniometer 360° to measure ankle dorsiflexion and plantar flexion. A manual goniometer is safe and has no harmful effects on the subject. It is a reliable and valid tool for measuring the ankle range of motion.[27] In measuring dorsiflexion and plantar flexion, the same starting position was used. The participant was positioned on the edge of a bed in a long sitting position, reclining to about 45°. A pillow was placed under the upper part of the lower legs to flex the knee to 20°–30°, with the heels lifted off the bed’s surface. The researcher ensured that the participant was comfortable during the procedure. Although alternative positions can be used to measure the range of motion, all the measurements in this study were taken using the long sitting position without any complaint from the participants and with no need to change the measurement position. The same procedure was repeated to confirm if there were any differences. The measurement was repeated three times. The axis of the goniometer was placed approximately 1.5 cm inferior to the lateral malleolus. The stationary arm was placed parallel to the longitudinal axis of the fibula, lining up with the fibula head. The moveable arm was set parallel to the longitudinal axis of the fifth metatarsal.[28] The same technique was performed for all participants in both groups.

Dynamic stability

The dynamic stability was determined by using the SWAY medical system. This instrument is reliable and valid in measuring ankle stability after comparing it with the Biodex Balance System.[29,30] The SWAY medical system has a protocol to measure stability. The device has six different protocols suitable for patient use. During the test, a participant holds the sensor device screen in front of their chest while standing on the balance board, which sends information about stability to the program. In this study, the test was conducted by asking the participant to stand in specific positions and to try their best to maintain stability. This study used the same protocol for all the participants. The differences in height, weight, and age were considered using personal files loaded into the system for each participant. This procedure helped them to measure stability more accurately.

Procedure

Before starting the measurement, the researcher explained the procedure to the participants, answered all questions, and addressed any concerns. The primary researcher filled out a data collection form and interviewed each participant to collect the relevant data. Each participant was asked if they had any ankle sprain in the past 2 years, had a musculoskeletal injury, had injuries during training, or had any special medical condition affecting stability. The affected leg of each participant was determined by asking which leg they had a sprain. The researcher took their weight and height measurements using the stadiometer and weighing scale. The participant was asked to lie down on the bed. The ankle joint was placed on the edge of the bed to ensure that the ankle joint was completely free. The researcher measured the dorsiflexion and plantar flexion range of motion passively for the ankle joint using a manual goniometer, with the lateral malleolus used as a landmark. The researcher began with the nonaffected side and then measured the affected side. A general warm-up of 10 min was done before the test. The SWAY medical system was used to measure dynamic stability. The participant was asked to stand on a balance board, hold the device and follow a set of instructions given by the researcher. The system measured the dynamic stability and produced immediate results for each stage after completing all the processes. The researcher began with the affected side. After completing this side, the researcher gave the participant a 5-min rest. All information was registered on the data collection form. No emergency was reported while collecting data because all the tests were conducted safely. Both groups received the same procedure.

Statistical analysis

The data were statistically evaluated using the PAST program (v. 3.02, University of Oslo, Oslo, Norway). The statistical significance was determined at ≤0.05 in this study. We used the Shapiro–Wilks test, observation of histograms, and Q-Q plots to determine whether data followed a normal distribution. Levene’s test confirmed the homogeneity of variance. Bonferroni correction test was used to avoid false-positive result. Numerical data were presented as means and standard deviations. An independent t-test was conducted to find statistically significant differences between the groups’ dynamic stability, dorsiflexion, and plantar flexion scores in affected and nonaffected limbs.

RESULTS

Table 1 summarizes the demographic characteristics of the participants in both groups. No significant differences between groups were found in age, weight, height, and body mass index.

Table 1.

Participant’s characteristics

	Healthy group		Injured group (ankle sprain)
	Mean±SD	Range	Mean±SD	Range
Age (years)	22.59±3.33	18–29	23.65±3.48	18–31
Weight (kg)	69.59±5.66	60–81	72.03±5.86	60–89
Height (cm)	176.84±5.32	168–191	178.59±4.74	172–193
BMI (kg/m2)	22.22±1.12	19.02–25.54	22.56±1.32	18.94–25.01

BMI: Body mass index, SD: Standard deviation

Table 2 shows significant differences in dominant leg range of motion (dorsiflexion [P = 0.0001] and plantar flexion [P = 0.0001]) between the healthy and injured groups, whereas no significant difference has been seen for nondominant leg range of motion.

Table 2.

Differences between healthy and injured groups for a range of motion (dorsiflexion and plantarflexion)

	Dorsiflexion		Plantarflexion
	Mean±SD (°)	Significance	Mean±SD (°)	Significance
Dominant leg
Healthy	18.75±2.19	0.00*	43.75±2.54	0.00*
Injured	12.65±3.35		37.81±5.07
Nondominant leg
Healthy	18.84±2.45	0.79	43.90±2.45	0.47
Injured	12.75±2.19		43.59±2.61

*Significant at ≤ 0.05 level.SD: Standard deviation

Table 3 shows significant differences between the dominant and nondominant leg range of motion (plantar flexion [P = 0.00024], dorsiflexion [P = 0.0001]) in the injured group. The healthy group does not show any significant difference between dominant and nondominant legs for (plantar flexion and dorsiflexion) range of motion.

Table 3.

Comparison between legs in the healthy and injured group for a range of motion

	Healthy group		Injured group
	Mean±SD (°)	Significance	Mean±SD (°)	Significance
Plantar flexion
Dominant leg	43.75±2.54	0.57	37.81±5.07	0.00*
Nondominant leg	43.90±2.45		43.59±2.61
Dorsi flexion
Dominant leg	18.75±2.19	0.74	12.65±3.35	0.00*
Nondominant leg	18.84±2.45		18.75±2.19

*Significant at ≤ 0.05 level.SD: Standard deviation

Table 4 shows that there were higher significant differences for dynamic stability in healthy participants than injured participants for their dominant (P = 0.0001) and nondominant (P = 0.001) legs.

Table 4.

Dominant leg and nondominant leg comparison between healthy and injured groups for dynamic stability (perimeter)

	Mean±SD	Significance
Dominant leg
Healthy	86.69±5.99	0.00*
Injured	57.43±17.33
Nondominant leg
Healthy	84.44±15.0	0.00*
Injured	74.60±6.89

*Significant at ≤ 0.05 level.SD: Standard deviation

Table 5 shows significant differences in dynamic stability in dominant and nondominant leg for the participants of healthy (P = 0.033) and injured (P = 0.00000023). The dominant leg of the healthy group shows higher dynamic stability than the nondominant leg. The nondominant leg shows higher dynamic stability in the injured group than the dominant leg.

Table 5.

Healthy and injured groups comparison between the dominant leg and nondominant leg for dynamic stability (perimeter)

	Mean±SD	Significance
Healthy
Dominant leg	86.69±5.99	0.03*
Nondominant leg	84.44±6.89
Injured
Dominant leg	57.43±17.33	0.00*
Nondominant leg	74.6±15.07

*Significant at ≤ 0.05 level.SD: Standard deviation

DISCUSSION

The objective of this study was to investigate the consequence of an ankle sprain injury on dynamic stability, dorsiflexion, and plantar flexion ROM in an injured and an uninjured leg. It was hypothesized that healthy and injured participants showed significant differences in ankle range of motion and dynamic stability. The hypothesis of this study was accepted with the findings. The result of the study shows significant differences in the dominant leg range of motion (dorsiflexion [P = 0.0001] and plantar flexion [P = 0.0001]) between the healthy and injured group, whereas no significant difference has been seen for nondominant leg range of motion. Significant differences between the dominant and nondominant leg range of motion (plantar flexion [P = 0.00024], dorsiflexion [P = 0.0001]) in the injured group existed. The healthy group does not show any significant difference between dominant and nondominant legs for (plantar flexion and dorsiflexion) range of motion. The results further show that there were higher significant differences for dynamic stability in healthy participants than injured participants for their dominant (P = 0.0001) and nondominant (P = 0.001) legs. The significant differences in dynamic stability in the dominant and nondominant leg existed for healthy (P = 0.033) and injured (P = 0.00000023) participants. The dominant leg of the healthy group shows higher dynamic stability than the nondominant leg. The nondominant leg shows higher dynamic stability in the injured group than the dominant leg.

A significant difference in dorsiflexion exists when the dominant leg is compared between the injured (ankle sprain) group and the healthy group. Conversely, no significant difference is found when the nondominant leg is compared between the two groups. This research concerns dorsiflexion, which is impaired by the decrease in normal ROM in an individual after an ankle injury in the injured leg. Soccer players with an ankle sprain are vulnerable to recurrent ankle sprain injury because of the limitation in dorsiflexion during noncontact injury situations.[31] The factors affecting the range of motion are caused by plantar flexion, which is the condition addressed in this study. This research aims to determine whether plantar flexion and ankle sprain differences exist. This finding is significant because most studies ignore the planter flexion condition in the case of ankle sprain injury.

Further, the range of motion comparison between the dominant leg’s healthy and ankle injury groups shows significant differences in plantar flexion. However, when the same procedure is applied to the nondominant leg of both groups, the result shows negative differences in plantar flexion. These findings indicate that the plantar flexion range of motion is affected after an ankle sprain injury in the injured leg. Moreover, plantar flexion may be one of the major factors causing recurrent ankle sprain injuries.[32] Regarding the ankle joint range of motion during active movement, the results indicate a significant difference between an ankle sprain and a plantar flexion range of motion. However, our findings disagree with Hadzic et al.[33] The main reason for this disagreement is that the researchers took a range of motion measurements of the ankle joint in active movement. By contrast, Grindstaff et al. and Henry et al. found that dorsiflexion was affected after ankle sprain injury regardless of whether the occurrence was an acute or a recurrent ankle sprain.[34,35] There are no issues with this, but examination and procedures should be done at the first measurement. The level of accuracy can be affected when the measurement is taken after an athlete has warmed up and performed exercises that may be exerting the muscle.

They are taking a passive range of motion yields more accurate results. The nondominant and the dominant leg were compared in the current study to investigate whether dorsiflexion or plantar flexion range of motion affects the unaffected leg in the injured group. An analysis was conducted on the injured ankle group to compare the two legs during dorsiflexion and plantar flexion. The results show a significant difference between the two legs in the same study. Moreover, the same procedure was conducted on the healthy group to determine whether ankle joint injury is the main reason for the limitation of range of motion. The comparison between the dominant and the nondominant leg in the same study for the healthy group included dorsiflexion and plantar flexion in both legs. The results show no significant difference between the two legs in the healthy group’s plantar flexion and dorsiflexion. The previous results support our findings on ankle dorsiflexion and plantar flexion range of motion in football players with a sprained ankle injury and confirm that ankle sprain is the major reason for the limitation of range of motion at the ankle joint.

This study tested dynamic stability using a balancing board to challenge soccer players. The common practice is to test on the floor, which would be far too easy for professional football players. Our results are consistent with those[36,37,38,39,40] which show that poor stability is a major issue after ankle sprain injury. Moreover, because such an injury can lead to a recurrent ankle sprain, the medical staff can consider stability deficiency in soccer players as a predictive factor for ankle sprain. Therefore, decreasing the rate of expected injuries and reducing the factors that can lead to an ankle sprain is important in designing proper injury prevention programs for soccer players.

Further, this study finds no significant difference between the dominant and nondominant legs of the healthy group. This result provides a worthy argument for stability among healthy soccer players; stability is generally at the same level for both legs. However, the medical staff should assess both legs, even healthy athletes. These results do not mean that stability is necessary in the healthy group. Rather, they clarify that stability is at the same level for both the dominant and the nondominant leg. Two reasons account for these findings. The first one is the training routine. For example, if athletes’ training schedules include balancing exercises, they will exercise both legs. If they miss balancing exercises, both legs will miss out on them. Therefore, the dominant and the nondominant leg are trained at the same level. The second reason is that if both legs are unaffected and uninjured, then both legs will be exercised at an equal level.

The current study findings on the healthy group confirm that the stability of the injured leg is negatively affected even after football players or patients have returned to their normal active lives. The study examined the dominant injured legs in the ankle injury group and compared them with the dominant legs of the healthy group to provide greater accuracy of measurements and results. As previously pointed out, stability training for both legs is strongly advised to be considered in the rehabilitation plan, not only as treatment for the injured ankle but also for reducing possible injury to the unaffected ankle in the future. Furthermore, if a patient or an athlete has a cast on, performing stability training for the unaffected leg, which can help in the recovery, is still possible.[41]

The study by Hale et al. investigates the effects of unilateral stability training in both lower limbs.[42] The study was conducted at a university clinical research laboratory on 34 participants divided into rehabilitation and control groups using a cohort study design. The participants received stability training twice a week during a 4-week program. Stability measurement was determined by the Foot and Ankle Disability Index sport, star excursion balance test, and the balance error scoring system to compare the groups. The results showed a significant improvement in both lower limbs of the participants when they received a unilateral stability training program.

Moreover, to confirm the findings, another randomized controlled trial was performed by Cruz-Díaz et al. performed another randomized controlled trial on 70 participants in a 6-week stability training program.[31] This study finds significant improvement in ankle stability after completing the training program. The subjects with ankle injuries show a significant difference in stability between the dominant and the nondominant leg. This variation in stability may be due to the effect of the injury. This result benefits clinicians, coaches, and trainers who deal with injured and uninjured athletes.

This study has some limitations. The study was conducted on male soccer players only. Therefore, our findings may not be generalized to include female soccer players because of the lack of female athlete participants in the current study. Moreover, all the participants were soccer players. Although other sports have the same activity level, our findings may not be generalized to include them. Rehabilitation plans and the type of exercises they receive are very important factors that may affect results; this is a limitation in the current study. Eversion or inversion range of motion and muscle power in the ankle joint was not measured. This aspect is considered a limitation since Abdel-Aziem and Draz find that restoring plantar flexion, eversion, inversion, and muscle strength functionally plays a role in preventing recurrent ankle joint sprain.[43] This finding supports our theory as a limitation of this study. Another limitation of the study is that the time frame from injury to the measurement was not uniform in all the participants.

CONCLUSION

As regards the outcome of an ankle sprain on the dorsiflexion and plantar flexion range of motion of the ankle, the study found significant differences between the injured limb and the sound limb. The injured affected and nonaffected limbs revealed a striking disparity in this range of motion. Therefore, the study demonstrated that ankle sprain causes stiffness and tightness of the ankle joint, which limits ankle movements. Based on the findings, this study could be used as a return-to-play criterion for athletes after ankle sprain injury to determine whether they are ready to return to play or need to continue a specific rehabilitation training program.

Research quality and ethics statement

This study was approved by the Institutional Review Board/Ethics Committee at Imam Abdulrahman Bin Faisal University, Dammam, Kingdom of Saudi Arabia (Approval #: IRB-PGS-2016-03-125; Approval date: Aug 28, 2016). The authors followed the applicable EQUATOR Network guidelines, specifically the STROBE Guideline, during the conduct of this research project.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.