A Survey of Musculoskeletal Injuries Associated with Zumba

Abstract

Zumba is a highly popular Latin-inspired dance fitness program with ∼14 million participants in 150 countries. However, there is little published data on the rates or types of injuries among participants. We surveyed a convenience sample of 49 adults (100% participation) in 5 Zumba classes in Hawai‘i. Participants described any prior Zumba-related injuries. We used t-tests and logistic regression to determine if participant demographics or intensity of Zumba classes were associated with injuries. Participants were mostly female (82%), averaged 43.9 years of age (range 19 to 69 years), and took an average of 3 classes/week (1–2 hours/class) for an average of 11 months. Fourteen participants (29%) reported 21 prior Zumba-related injuries. Half of the 14 injured sought care from medical providers for their injuries. Of the 21 injuries, the most frequently injured sites were knees (42%), ankles (14%), and shoulders (14%). Participants with Zumba-related injuries did not differ significantly in age, months of Zumba, or hours/class compared to those who did not experience injuries. However, participants who reported injuries took significantly more classes/week (3.8 versus 2.7 classes, P = .006) than non-injured participants. In logistic regression, taking more classes/week remained significantly associated with injuries (odds ratio 3.6 [95% confidence interval 1.5 – 8.9, P = .006]) after controlling for age, gender, months of Zumba, and hours/class. Given Zumba's health benefits, our finding that 1 in 4 Zumba participants have experienced injuries indicates the need to improve Zumba routines, instructor training, and health provider counseling to reduce injury risk.

Introduction

Zumba is an extremely wide-spread Latin-inspired dance exercise program that started in 2001 and has been gaining rapidly in popularity. Its motto is “Ditch the workout. Join the Party.” ^1,2 An estimated 14 million people have participated in Zumba in over 150 countries. There are a wide variety of Zumba classes targeting specific participant groups, including children and elderly persons.^1,2 Zumba was predicted to be one of the top 10 fitness trends in 2012 by the American College of Sports Medicine (ACSM) based on a survey of more than 2,600 fitness professionals.³ From a business point of view, Zumba is an important part of the multi-billion dollar fitness industry. There are Zumba DVDs, video exercise games, apparel, and accessories.³ The goals of Zumba are for participants to improve strength, balance, coordination, and cardiovascular endurance.^1,2 Standard Zumba classes use high energy Latin and international beats, and usually last 1 to 2 hours.² As a popular form of exercise, Zumba can be a very important part of improving health and reducing obesity-related diseases, such as diabetes and hypertension.³ Zumba also helps participants meet the ACSM recommendation of 150 minutes of cardiovascular exercise per week (30 minutes per day, five days per week).⁴

Despite the popularity of Zumba, its relatively new development means there are few, if any, formal studies on the rates or types of injuries experienced by Zumba participants. Our literature search using PubMed found only one peer-reviewed study of Zumba, which focused on the benefits of Zumba in hemodialysis patients.^5,6 However, anecdotally, doctors are seeing more Zumba-related injuries.^7,8 The Accident Compensation Corporation, which insures all New Zealand residents and visitors, received more than 1,600 claims for Zumba-related injuries during a 2 year period.⁸ Understanding the types of injuries that are common in Zumba can help the design of interventions to prevent unnecessary injuries. The Zumba fitness industry could better train Zumba instructors to develop routines that minimize the risk for injuries, and educate Zumba participants on how to avoid getting hurt. Since many individuals see their healthcare providers before starting exercise programs, providers could better counsel their patients on whether Zumba is an appropriate form of exercise for them, on how to avoid injuries, and promote awareness of common Zumba-related injuries.⁹ Thus, the purpose of this study was to determine the frequency and type of injuries among Zumba participants.

Methods

This study was conducted with a convenience sample of 49 adults (age 18 and older) in 5 Zumba classes taught by different instructors at 5 different locations in Hawai‘i. Participants were randomly selected and asked to complete a short written survey on their age, gender, how long they had taken Zumba, number of classes per week, hours per class, if they had ever experienced any injuries from Zumba, and if yes, the body part that was injured, and if they sought medical attention for their injuries. Surveys were given before the Zumba classes and participants received no financial incentives. Simple descriptive analyses were used to describe the rate and type of injuries, and treatment sought. Bivariate T-tests and multivariate logistic regression were conducted using SAS 9.2 (SAS Institute, Cary, NC) to determine whether age, gender, duration of Zumba participation, number of classes per week, or length of Zumba classes were significantly associated with injuries. This study received IRB approval from the University of Hawai‘i Human Subjects Program.¹⁰

Results

Demographics

Forty-nine participants completed the survey (100% response rate). Participants were on average 43.9 years old (standard deviation [SD] 12.1, range=19 to 69 years), and most were female (82%) (Table 1). Participants reported having taken Zumba classes for an average of 11.8 months (SD 6.7, range=3 to 30 months) and 3 classes per week (SD 1.3, range=1 to 5 classes per week). Classes taken by the participants ranged from 1 to 2 hours in duration.

Table 1.

Demographics of Study Participants (N= 49)

	Mean	Standard Deviation	Range
Age (years)	43.9	12.2	19 to 69
Female*	91%	n/a	n/a
How long took Zumba class (months)	11.8	7	1 to 30
Classes per week	3	1.1	1 to 5
Hours per class	1.2	0.4	1 to 2

^*Five out of 49 participants did not give gender

Injuries

Fourteen of the 49 participants (29%) reported having experienced an injury while taking Zumba. Some participants reported multiple injuries, thus representing a total of 21 injuries. Of the 14 participants who experienced injuries, 50% sought medical attention, 14% self-treated (eg, applying ice, changing shoes, etc) and 36% did not seek treatment nor self-treat (Table 2). Of the 21 injuries, the most common anatomic site of injury was the knee (42%). The remainder of the injuries involved the ankle/foot (14%), shoulder (14%), elbow (5%), calf (5%), lower back (5%), neck (5%), thigh (5%), and muscle pain (5%).

Table 2.

Zumba-related Injuries

	Number of participants	Percentage of participants
Participants reporting injuries (n= 14)
Sought medical treatment	7	50%
Self-treatment only	2	14%
No treatment needed	5	36%

Risk for Injury

Participants who had experienced Zumba-related injuries (Injured) versus those who did not experience injuries (Non-injured) did not differ significantly in age (44.9 versus 43.5 years, respectively; P = .74), how long they had taken Zumba (13.1 versus 11.2 months, respectively; P = .35), or the number of hours per class (1.21 versus 1.17 hours, respectively; P = .75) (Table 3). However, in t-test analyses, injured versus non-injured participants took more classes per week (3.8 versus 2.7 classes, P = .006). In logistic regression, the number of classes per week remained significantly associated with injury (odds ratio 3.6 [95% confidence interval 1.5 – 8.9, P = .006]) even after controlling for age, gender, months of Zumba, and hours per class (Table 4). Reports of previous injuries were 56% amongst participants who said they took 4 or more classes per week versus 15% amongst participants who took 3 or fewer classes per week (Figure 1).

Table 4.

Zumba-related Injury - Adjusted Odds Ratio

	Adjusted Odds Ratio	95% confidence interval		P-value
Age (years)	1.0	0.9	1.1	.83
Female	1.5	0.1	26.2	.76
Months taken Zumba	1.0	0.9	1.1	.85
Classes per week	3.6	1.5	8.9	.006
Hours per class	0.7	0.1	5.8	.76

Figure 1.

Injuries by Number of Classes per Week

Discussion

Twenty-nine percent of our study participants reported injuries associated with Zumba. Of those who were injured, half sought formal medical attention. This is probably why healthcare providers have reported seeing more patients for injuries in Zumba despite few or no published studies on rates of Zumba injuries.^7,11,12 Our results indicate that injuries do occur and are often serious enough for individuals to seek medical treatment. Given the popularity of Zumba and the importance of regular exercise to improve physical fitness,^4,13–16 the Zumba fitness industry, public media, and healthcare providers need to look for ways to support Zumba while minimizing the risk for injuries among participants. Prospective studies are also needed to compare rates of injury in Zumba to other forms of dance fitness classes such as aerobics and jazzercise.

The anatomical sites of injuries in this study included the knee, ankle, thigh, shoulder, neck, and back, which are consistent with the range of Zumba-related injuries (ankle sprain, ankle fractures, torn meniscus, overuse injuries) seen by surgeons as reported by the American Academy of Orthopedic Surgeons.¹¹ Consumer Reports' Medical Advisor, Dr. Orly Avitzur, described treating patients for Zumba injuries ranging from ankle sprains to hip bursitis to knee problems requiring surgery.¹¹ Zumba is based on dance moves, and our findings are similar to injuries observed among dancers (lower extremities, hip, and back injuries) according to a systematic review in the Journal of Dance Medicine and Science.¹² Another article in the Journal of Dance Medicine and Science conducted a survey on professional modern dancers that showed 40% suffered injuries to the foot and ankle, 17% had injuries in the lower back, and 16% had injuries to the knee.¹⁷

There has been speculation that new participants to Zumba are more susceptible to injuries because Zumba may be their first form of physical activity in a while.¹¹ In this study, there were no significant differences between injured and non-injured participants in how long they had been taking Zumba. Most participants reported taking Zumba for almost a year. However, the study did not ask about the timing of injuries, and therefore did not determine whether injuries occurred when participants first started Zumba or after they had been taking Zumba for some time. Further studies would be helpful to determine if interventions to reduce Zumba-related injuries should target new participants in particular, or all Zumba participants regardless of experience level.

This study did detect an association between injuries and taking more classes per week, with more than half of those taking four or more classes per week reporting prior Zumba- related injuries. This has also been observed in research on classical ballet and jazz/contemporary dancers, where greater weekly frequency of practice was associated with occurrence of injuries.¹⁸ Health providers could counsel participants to start with three or fewer classes per week, rest one or two days in between classes, and decrease the frequency of their workouts if they start to feel pain, discomfort, or fatigue.^9,19,20

Although Zumba is a relatively new form of exercise, dance and fitness programs such aerobics and jazzercise have been around for longer and also involve many lateral (side-to-side) movements set to music.²¹ The types of injuries reported here are similar to what has been found for dance and aerobics (Achilles tendon pain, calf pain, shin splints, plantar fasciitis, etc).^9,20 Thus, applying recommended injury-reduction techniques from dance, aerobics, and jazzercise to Zumba may be reasonable.

1. Longer Warm-ups. Warm-ups and cool-downs that include stretching, strengthening, and balance exercises have been found to be important for sports in general and in aerobics.^21,22 Warm-ups allow the body to loosen and cause a gradual increase in heart rate. Cool-downs allow the heart rate to come down slowly and burn off lactic acid and adrenalin.^9,21 Instructors may try to lengthen warm-ups to ensure participants are not going into the Zumba workout with cold muscles. Although controlled studies are needed to confirm their effectiveness, the ACSM still recommends “warm-up and cool-down” methods to reduce musculoskeletal injuries and complications.⁴ Thus, Zumba instructors should be aware of the importance of appropriate warm-ups and cool-downs when designing their Zumba routines.

2. Wear proper shoes. Both Zumba and aerobics include many side-to-side movements. In aerobics, some injuries are due to improper shoes and floor surfaces.²⁰ Having the correct shoes may also decrease the risk for injury in Zumba.^7,11,23 Participants may not be aware that the recommendation is to wear dance shoes or other shoes that provide stability for side-to-side motion and allows twisting and turning. Running shoes are not recommended because they have treads, which can cause the shoes to stick to the floor.¹¹ The American Academy of Podiatric Sports Medicine (AAPSM) recommends having the right size toe box and a thick strap support for forefoot stability to prevent slippage of the foot.²¹ The official Zumba website (as well as other Zumba websites) could promote greater awareness of appropriate shoes for Zumba; instructors must be trained to include this information in handouts given to participants during class sign-up. Healthcare providers, who recommend Zumba to patients, should also alert them to the need for proper shoes.

3. Stay hydrated. Healthcare providers should counsel their patients to stay hydrated to prevent nausea, dizziness, muscle fatigue, and cramping.²¹ The ACSM recommends drinking 8–12 ounces of water 10–15 minutes before exercise, and 3–8 ounces of water every 15–20 minutes during exercise (sports beverage if exercising greater than 60 minutes), and 20–24 ounces of water or sports beverage after exercise for every 1 pound lost.²⁴ Furthermore, a healthy carbohydrate and protein snack every 2–3 hours can keep a steady source of energy and replenish depleted energy stores.⁹

4. Cross-training. Cross training, such as running, lifting weights, swimming, or cycling, can also help decrease the risk of injury.²⁰

5. Smaller Zumba classes. Being in overcrowded classes may place participants at higher risk for injuries because the instructor may not be able to see everyone and people may run into each other.¹¹ One Zumba instructor recommended a class size of no more than 25 participants with 2 instructors so one instructor can teach while the other instructor walks around to see if anyone needs help.^7,23

6. More training for Zumba instructors. Zumba is a registered trademark and persons wishing to teach Zumba must be licensed by the Zumba Academy.^2,8,25 Regardless of experience, all trainees take a 1 day class (10 hours) and are taught movements from 4 types of dance: merengue, salsa, cumbia, and reggaeton. Afterwards, Zumba instructors are allowed to create their own dance routines with their own music and moves. ^2,8,26 Thus, while there is some standardization due to licensing and training, there is also likely to be significant variation among actual Zumba routines and in instructor experience. Participants should ask their instructors how long they have been teaching Zumba and about their fitness backgrounds, such as dancing experience or fitness certification.⁷ More research is needed on whether specific dance movements are more likely to increase injuries, and whether Zumba training should teach potential instructors which dance moves to avoid.

7. Picking an appropriate Zumba class. Healthcare providers should also advise individuals to pick Zumba classes targeted to their specific age groups or other health demographics as appropriate. For instance, Zumba Gold modifies movements and pacing to suit the needs of older adult and Zumbatonic is specifically choreographed for children ages 4–12. Aqua Zumba is a water-based workout which is integrated with traditional aqua fitness.²

8. Treating with Rest, Ice, Compression, and Elevation of injured area (RICE). Health providers can counsel their patients on how to treat musculoskeletal injuries from Zumba with RICE as appropriate.^9,20 When people are recovering from their injuries, they should be pain-free for more than 1 week, start back slowly, and not at the same intensity as prior to their injuries.⁹

Limitations

Our study was a retrospective study of 49 participants and a larger, prospective study would help confirm our findings. We did have a 100% participation rate, and reported rates of injuries were relatively common (29%). However, our participants' report of rates of injury, injury location, and medical treatment are subject to recall bias. Since we surveyed only current Zumba participants, injuries may have been underreported if persons with major injuries did not return to Zumba. We also did not inquire about participants' fitness status prior to starting Zumba, their body mass index (height or weight), or any past injuries not related to Zumba, that could affect their risk for injury while participating in Zumba.¹⁸ We did not define “injury,” however participants who reported having experienced injuries provided details such as location and whether they sought formal care or self-treated.

Conclusion

Our study found that 1 in 4 Zumba participants reported previous Zumba-related injuries, with higher rates of injury among participants taking more classes per week (56% among those taking 4 or more classes per week). Given the benefits of regular physical activity, healthcare providers should continue to support patients' participation in Zumba but actively counsel them on potential ways to minimize injury, such as choosing appropriate footwear, starting with 3 or fewer classes, finding an experienced instructor, and having proper hydration.

Table 3.

Factors Associated with Zumba-related Injuries

	Injured	Non-injured	t-test P-value
Age (years)	44.9	43.5	.74
Months taken Zumba	13.1	11.2	.35
Classes per week	3.8	2.7	.006
Hours per class	1.2	1.2	.75

Conflict of Interest

None of the authors identify a conflict of interest.