Snowsport resort workers have one of the highest occupational injury rate classifications of all sectors. The average annual provincial claims cost over the five years preceding 2012 was $2.3 million in British Columbia alone, with an injury rate of 8.0 claims per 100 estimated person years of employment [
Very little work has been done to examine the etiology of these injuries. Sixty percent of professional ski instructors reported a history of pain [
Another potential contributing factor to occupational injuries is the impact of mild hypoglycemia [
Given both the prior injury histories and frequent chronic pain in this occupational sector as well as restricted access to food and fluids during the day, it may be that impaired proprioception and psychomotor vigilance are factors in the high injury rate seen in snowsport resort employees. In order to investigate the possible contribution of these parameters to injuries in this population, this study aimed to evaluate the regional relative risk of the spine and peripheral joints and the glycemic and hydration levels and coincident motor reaction time and vigilance levels in ski and snowboard instructors, patrollers, and lift attendants. The primary objective was to determine if injury rates are reduced following exposure to a program of corrective joint stability exercise and dietary counseling to stabilize blood glucose and hydration.
Five volunteers in each job designation (lift attendant, instructor, and patroller) were recruited at each of five snowsport resorts (
The initial data collections occurred within the first month of the winter season at each resort (Figure
The experimental timeline.
Subjects completed a series of functional movements to evaluate the ability to actively maintain the test joint segment (knee, lumbar spine, or shoulder) in an anatomically neutral position while challenging it with independent movement at the adjacent joints, as would be required during normal daily work. These assessments were adapted from tests developed by Performance Stability (Ludlow, UK), which has previously been validated for use in functional movement assessment [
In brief, regional relative risk was assessed by evaluating the ability to control movement at the knees, lumbar spine, and shoulder during nonfatiguing slow movements, as well as with fatigue during rapid movements. Prevention of a defined motion at the site of the regional link was rated as a pass (able to demonstrate good active control) or fail (unable to actively prevent uncontrolled movement). All tests were filmed from two angles, lateral and either anterior or posterior view, and scored according to a predefined set of criteria by two independent assessors. The desired movement was demonstrated immediately prior to performing the test; the subject then attempted the movement with correction until being confident about the task. Verbal feedback was provided throughout the learning phase.
The first test evaluated control of flexion and rotation at the lumbar spine during the first 50° of hip flexion. The subject stood with one foot positioned two foot lengths posterior to the lead foot while holding a 10 kg bar (as in lifting a pair of skis). The weight held in this position, anterior to the knee, increased flexion load on the lumbar spine. The posterior leg was held in the extended position and raised off the ground, thus increasing the rotational stress at the lumbar spine and the hip. The task was to squat three times to 45° of knee flexion on each side without rounding at the lumbar spine or rotating the pelvis. Inefficient control of hip rotation during this squat was of concern as it produces increased torsional stress on the knee joint, which was viewed as displacement of the knee from midline.
The second test was an alternating lunge split jump. This test assessed the ability of each subject to control knee, pelvis, and lumbar spine positioning during forces generated with jumping and eccentric loading during landing (as in downhill skiing or boarding). The subject started with a distance equal to the measure of three of their foot lengths between the front and back feet and performed a series of 10 alternating split squat jumps, landing with the anterior knee at 90° and immediately lifting the heel of the front foot. This landing position was held for five seconds prior to the next jump, where the lead foot was switched while in the air. The destabilized hold position (with the heel raised) for each of the 10 jumps without rest increased the time under tension and induced fatigue and also tested for the ability to limit rotational stress from the distal joint complex on the knee (as would occur during turning on skis or a snowboard or during destabilization due to a slip or trip). Other movements evaluated were whether the lumbar spine flexed, extended, and/or laterally bent during jumping or landing and if the hip/leg musculature was able to keep the front knee in midline throughout the test. This was of interest because hip stability has been correlated with injuries to the anterior cruciate ligament of the knee [
The final test evaluated the ability to maintain scapular-thoracic stability and control of lumbar extension with loaded overhead arm actions. Subjects began in a bridge position from knees and elbows with the lumbar spine in a neutral posture. One arm was raised overhead for 3 successive repetitions prior to switching sides. Raising the arm increased extension and rotational forces on the lumbar spine. With poor stability the scapula(e) of the stabilizing arm and/or the raised arm were/was observed to lose contact with the thoracic wall, resulting in increased muscular stress on the cervical spine and poor biomechanical patterning at the glenohumeral complex.
Capillary blood samples were collected from fingertip using standard sterile procedure. Samples were analyzed immediately using the Contour Glucose Monitoring System (Bayer Healthcare LLC, Toronto, ON, Canada) calibrated twice daily. Eight-hour fasting blood samples were collected at the start of the day; subjects were then encouraged to follow their usual dietary and hydration practices. Approximately every 2 hours thereafter the research team visited each participant wherever they were working to collect a blood glucose sample and complete the psychomotor vigilance testing.
Psychomotor vigilance testing was conducted using Brain Checkers software, Version 3.01 (Behavioral Neuroscience Systems LLC, Springfield, MO, USA) run on Palm Tungsten E2, (Palm Inc. Milpitas, CA, USA). The tests were designed to evaluate simple reaction time, 2-choice reaction time, short-term memory, and visual information processing. The first test was 30 sec in duration and measured simple reaction time as speed of motor response to a repeated unexpected visual stimulus. The second test assessed the ability to recall and process numerical information accurately in a 2-minute continuously running 2-choice reaction time test. These same parameters were further evaluated during the third test, which relied on visual pattern recognition. Reported parameters include the mean reaction time for each session and parameter, as well as a calculated Tput statistic that represents the number of correct responses per minute of available time to respond. The complete protocol has been previously described [
Each subject completed a familiarization session at the start of the season during the initial data collection and functional movement assessment, consisting of five trials of each of the three tests. Previous work has shown that after 3 trials the learning curve levels off, and after five trials there is no further improvement [
Participants were also asked to record and/or report symptoms of falling blood glucose and counterregulatory hormones or dehydration such as hunger, fatigue, irritability, inability to focus, dizziness, confusion, nausea, tremor, and sweating at each on-snow testing session.
Body mass was recorded prior to the start of the workday and again just prior to the worker leaving for home (bladder empty, subject wearing only underwear) using the SR Model SR241 scales (accuracy = 0.2% ±1 digit, resolution = 0.1 kg, SR Instruments, NJ, USA). Hydration level was estimated based upon the assumption that each kilogram loss represented a reduction in body water by 1 liter [
Two- or 3-day diet records were completed by each participant according to specific criteria for accuracy; careful instructions on how to measure, define, and record all food and drink consumed were given in both written and oral formats. Verbal 2-hour diet recall was also taken at the time of each blood glucose sample. Dietary analyses were made on the basis of a minimum of three full days using Diet Analysis Plus, Canadian version 9.0 (Wadsworth/Thompson Learning, Scarborough, ON, Canada). The nutritive requirements were based upon the Dietary Reference Intakes (DRI) [
Workload was assessed by heart rate, recorded every 15 seconds for two full workdays on each participant (Actiheart system, Mini Mitter Co. Inc, Bend, OR, USA).
Five years of historical injury records were obtained from each of the five test resorts (2005/06–2009/10 winter seasons). Only records for patrollers, lift operators, and snowsport instructors were examined. Claims for all workers in these three job classifications were categorized based upon First Aid (FA) only (report made but no followup required), Medical Aid (MA) when the injury was examined by a physician (may have resulted in diagnostic tests, rehabilitative treatment, and/or modified duties), or Lost Time (LT) where the worker was unable to work and a claim for lost wages was made. The number of claims in each category was recorded for each year and a 5-year average was calculated. This process was repeated at the end of the 2010/11 season for claims made during the first year of the study and again at the end of the 2011/12 season for claims made during the season in which the preventative program was administered.
In addition, a request was sent out through the industry safety association for resorts that had not participated in the study to share their injury data for comparative purposes. Four resorts submitted summary data listing the number of injuries in each category for all patrollers, instructors, and lift operators working at each of the resorts during the two seasons over which the study was conducted. There was no limitation on these areas implementing their own safety programs. Since the areas ranged in size, number of employees, and employee work exposure and it was not possible to establish whether the same criteria for classification of injuries were used at all areas, the comparisons between injury rates were made as relative change over time within each resort.
A worksite health and wellness program designed to build healthy eating and drinking behaviors within the lifestyle and resources of a young snowsport resort worker and to establish neutral postures and stability at the lumbar spine, knee, and shoulder was offered to all employees at the five test resorts. During fall staff training, a short presentation (30 minutes–1 hour) open to all staff described the findings of the first year of the study, and briefly described the nutrition and proprioceptive program. In addition, each of the five participating snowsport areas selected 15 new volunteers (five in each job category of lift operators, patrollers, and instructors) to receive printed materials and attend half-hour workshops on nutrition and proprioception.
The nutrition workshop covered the three basic types of foodstuffs (carbohydrates, proteins, and fats) and their digestion times. The main points of focus were on how to maintain euhydration and to consume small low-fat, complex carbohydrate, and lean protein snacks every 2-3 hours during the workday to stabilize blood sugar. Glycogen replenishment was also recommended following high-activity days. Strategies for shopping, cooking, and packing of healthy meals on a budget and while living at a snowsport resort were also provided. Discussion on limiting alcohol and other recreational substance use was encouraged.
The proprioception workshop focused on learning how to position one’s body into a posture with the spine and pelvis in neutral position. Participants then learned to stabilize this neutral posture while standing (in ski or snowboard boots), sitting (as on a chairlift), or moving (while performing work tasks, carrying a pack, skiing, or riding). Simple proprioceptive drills to help increase stability at the lumbar spine, hip, knee, and shoulder were presented and participants were encouraged to utilize the drills regularly. The increase in functional movement stability was stressed from the perspective of enhanced performance as well as a decrease in the risk of injury.
Although only 15 workers at each resort attended the workshops and were provided with the printed materials, the workshop participants were encouraged to share the information within their departments. Supervisors from each outdoor department were also invited to share in the more detailed information and were provided with strategies to support the program on a biweekly basis throughout the season. In addition, all workers had access to a Facebook page for the program with regular postings on tips, recipes, exercises, fun activities, and other engaging platforms to support the program focal points of quality nutrition, hydration, fitness and proprioception, and a healthy lifestyle.
All means were reported as mean ± 1 SD. After testing for normalcy and equal variances, injury rate comparisons were made using analysis of variance (ANOVA), followed by paired (historical) or independent (between areas)
Demographic information is presented in Table
Demographic information for the 75 study participants collected during the first season at five snowsport resorts in Western Canada. Data are presented as mean ± SD or as a percentage of the number of volunteers.
Patrollers | Instructors | Lift operators | |
---|---|---|---|
Age |
|
|
|
% Males | 84% | 54 % | 78% |
% Smokers | |||
Tobacco | 0% | 13% | 17% |
Other | 28% | 8% | 40% |
% Skiers | 80% | 56% | 43% |
% Telemark | 20% | 0% | 0% |
% Snowboard | 0% | 39% | 47% |
% Both board and ski | 0% | 4% | 13% |
Years of experience |
|
|
|
Participates in recreational physical activity | 72% | 46% | 33% |
% Body fat | |||
Males |
|
|
|
Females |
|
|
|
BMI | |||
Males |
|
|
|
Females |
|
|
|
Prevalence of patrollers, instructors, and lift operators reporting at least one previous injury reported as a percentage of those interviewed (
Patrollers | Instructors | Lift operators | |
---|---|---|---|
Previously injured | 80% | 92% | 88% |
Shoulder | 45% | 38% | 37% |
Back | 45% | 42% | 42% |
Knee | 30% | 50% | 42% |
Ankle | 20% | 42% | 37% |
Chronic pain | 76% | 92% | 84% |
Functional movement analysis results for 75 snowsport resort employees. Data collected during the first season at five resorts in Western Canada. Scores are a unitless number representing the number of movement criteria displayed during the test. A higher score indicates a lower ability to stabilize the lower back, hip, knee, or shoulder joints during loaded movement.
Performance matrix | Patrollers | Instructors | Lift operators | % Participants* with good stability |
---|---|---|---|---|
Single leg knee bend |
|
|
|
7% |
Lunge jump |
|
|
|
3% |
Push-up arm lift |
|
|
|
11% |
Mean ± SD time spent (minutes) in each heart rate zone for each of the three occupational groups for a day of work. b/min: beats per minute. Data collected at five snowsport resorts in Western Canada during the first season of the study (
All of the study participants in year one had normal blood glucose levels; the mean ± SD fasting value was
Mean ± SD blood glucose levels during a day of work for patrollers, instructors, and lift operators while consuming their normal diet. Data collected at five snowsport resorts in Western Canada during the first season of the study (
The results of the reaction time and cognitive processing testing are presented in Figures
Mean ± SD simple reaction time responses (msec) during a day of work for patrollers, instructors, and lift operators. Data collected at five snowsport resorts in Western Canada during the first season of the study (
Mean ± SD two-choice reaction time in response to a numerical memory task, normalized for accuracy and represented as throughput (TPut), a unitless parameter. Data collected at five snowsport resorts in Western Canada during the first season of the study (
Mean ± SD two-choice reaction time in response to an unexpected complex visual pattern normalized for accuracy and represented as throughput (TPut), a unitless parameter. Data collected at five snowsport resorts in Western Canada during the first season of the study (
A historical examination for time of day of injury was also made for the five participating resorts. Over a 6-year time span (2005–2011), 69 ± 12% of injuries occurred during a total of three hours, composed of late morning or afternoon (Figure
The mean ± SD number of injury incidents occurring at a time of day when workers were likely to have been hypoglycemic (10:30–12:00 and 15:30–17:00) as a percentage of the total number of injury incidents reported for that year. *Significantly less than previous years,
A summary of the diet records is presented in Table
Dietary intake as reported from two- or three-day diet records for 75 patrollers, instructors, and lift operators at five ski resorts in Western Canada during the first year of the study. Data is represented as mean ± SD. The Recommended Dietary Allowance (RDA) is provided for comparison [
Patrollers | Instructors | Lift ops | RDA | |||||
---|---|---|---|---|---|---|---|---|
Men | Women | Men | Women | Men | Women | |||
Kcal |
|
|
|
|
|
|
2700 kcal | 2100 kcal |
Protein (g) |
|
|
|
|
|
|
0.8 g/kg body wt | |
Carbohydrate (g) |
|
|
|
|
|
|
>130 g | |
Total fat (g) |
|
|
|
|
|
|
<25–35% calories | |
Saturated fat (g) |
|
|
|
|
|
|
<7% caloric intake | |
Monounsaturated fat (g) |
|
|
|
|
|
|
<10–25% calories | |
Polyunsaturated fat (g) |
|
|
|
|
|
|
<8–10% calories | |
Trans fatty acid |
|
|
|
|
|
|
<1% caloric intake | |
Omega-6 linoleic acid (g) |
|
|
|
|
|
|
17 g | 12 g |
Omega-3 linolenic acid (g) |
|
|
|
|
|
|
>1.6 g | >1.1 g |
Cholesterol (mg) |
|
|
|
|
|
|
<200–300 mg | |
Total fiber (g) |
|
|
|
|
|
|
>38 g | >25 g |
Total sugar (g) |
|
|
|
|
|
|
<25% caloric intake | |
Total water (L) |
|
|
|
|
|
|
3.7 L | 2.7 L |
Thiamin (mg) |
|
|
|
|
|
|
1.2 g | 1.1 g |
Riboflavin (mg) |
|
|
|
|
|
|
1.3 mg | 1.1 mg |
Niacin (mg) |
|
|
|
|
|
|
16 mg | 14 mg |
Vitamin B6 (mg) |
|
|
|
|
|
|
1.3 mg | |
Vitamin B12 (mcg) |
|
|
|
|
|
|
2.4 mcg | |
Folate (DFE) (mcg) |
|
|
|
|
|
|
400 mcg | |
Vitamin C (mg) |
|
|
|
|
|
|
90 mg | 65 mg |
Vitamin D (IU) |
|
|
|
|
|
|
600 to 4000 IU | |
Vitamin A (RAE) (mcg) |
|
|
|
|
|
|
900 mcg RAE | 700 mcg RAE |
Alpha-tocopherol (Vit E) (mg) |
|
|
|
|
|
|
15 mg | |
Calcium (mg) |
|
|
|
|
|
|
1000 mg | |
Iron (mg) |
|
|
|
|
|
|
8 mg | 18 mg |
Magnesium (mg) |
|
|
|
|
|
|
420 mg | 320 mg |
Potassium (mg) |
|
|
|
|
|
|
>4700 mg | |
Zinc (mg) |
|
|
|
|
|
|
11 mg | 8 mg |
Sodium (mg) |
|
|
|
|
|
|
<2300 mg |
Highly significant reductions in medical aid and lost time claims were observed for all employees in the three test job classifications of patroller, lift operator, and instructor, at all five resorts where the nutrition and proprioceptive program was provided (Figure
The mean ± SD number of injury incidents for all patrollers, lift operators, and instructors working at five test snowsport resorts prior to and following implementation of the dietary and proprioceptive program (2011/12 season). The prior to 2010 data include up to five years of historical records for all workers in the three job categories. FA = First Aid report only, MA = Medical claim only, and LT = Lost time. *Significantly less than previous seasons, where
The primary outcome of this investigation was a large reduction in the number of recordable incidents in patrollers, instructors, and lift operators working at five snowsport resorts in Western Canada during a season where a nutritional and proprioceptive training program was used (Figure
These findings support previous reports that stabilizing blood glucose levels can significantly impact measures of vigilance including reaction time, cognition, memory, and decision making [
The possibility that some of the improvements in psychomotor vigilance in the previous studies and the reduction in injury rates observed in the current study were due to maintaining euhydration cannot be excluded. Based on the use of change in body mass from the start of the day to the end of the workday, the estimated mean level of dehydration in the first season of the current study was close to the 2% loss at which dehydration has been shown to impair cognition and reaction time [
In addition to stabilizing blood sugar and maintaining hydration levels, the very positive outcome of reduced injuries in patrollers, lift operators, and instructors working at the five test resorts using the training program in the second season was likely due to the inclusion of proprioceptive exercise that was specific to the movement challenges faced by these workers, but which were simple to use and could be incorporated into the workday. Although (as for the nutritional training) we have no direct evidence of altered behavior in those undergoing the training, given the frequency of reported previous injuries (Table
Several groups have shown that individuals with a previous history of low back pain who are asymptomatic may have the same amount of total hip and lumbar range of motion available during forward bend as healthy subjects, but they moved differently in the first 40° of forward flexion the noninjured group, producing increased flexion stress on their lumbar spine in the early part of a functional bend [
Many of these studies have looked at using balance, plyometric, and agility components to reestablish recruitment patterns and improve joint stability following soft tissue injury [
Fortunately, research has also shown that proprioceptive training can increase the speed of recruitment, restoring the protective reflex [
As with most applied research, there are some methodological considerations regarding the findings of the current study. Due to the nature of the worksite environment and the culture of the subject group there were many uncontrolled variables including but not limited to weather, exposure to moderate altitude, snow conditions, equipment, work hours, extracurricular activities, and a seasonal work force. Employee turnover prevented retesting of subjects or followup to determine the effect of employee training on behavior. In addition, each resort had its own procedure for classifying and recording injury events, making it difficult to compare results between areas. These factors notwithstanding, the objective observations in the significant reduction in the number of injuries sustained in all five resorts that utilized the nutritional and movement training program speak strongly in favor of the positive effect of a culturally and contextually specific health and wellness program in reducing injuries in patrollers, instructors, and lift operators working at snowsport resorts. The study findings indicate that providing these young workers with quality information in a format that is meaningful to them was effective in decreasing occupational injuries in spite of the inability to ensure that all employees complied or were even exposed to the training in an ideal manner.
The integration of occupational injury prevention and worksite health promotion is becoming an area of focus, as medical and insurance costs continue to rise. The components of the program utilized in the current study are in compliance with the recommendations for an integrated worker health program as outlined by CDC NIOSH’s Total Worker Health Program [
Given the high rates of injury common at snowsport resorts and the escalating costs of these injuries, combined with limited recourses available for employee training and the fact that compliance with healthy lifestyle behavioral change programs is often poor, the inclusion of this type of low-cost, highly effective, workplace intervention is highly recommended.
The findings of the current investigation provide evidence that integrated worksite health and wellness programs that encourage healthy eating patterns to stabilize blood glucose levels and maintain euhydration, combined with increased postural awareness and joint stability exercise, can help to significantly reduce occupational injury rates in ski resort workers. The difficulties of conducting research in a workplace setting notwithstanding, further investigations into these types of injury prevention programs are warranted.
There is no conflict of interest associated with this work. The author has never had a commercial interest at any time in the past, or has any agreement to do so in the future, with any of the manufacturers of materials or instrumentation used in this study. The training program developed in this study will be used for educational purposes.
This research was supported by funds from WorkSafeBC through the Focus on Tomorrow program. Each of the participating ski resorts provided complementary lift tickets, meals, and accommodation during the data collection as well as covering travel expenses for the research staff. This season 3 resorts are continuing to implement the program and collect injury data. These resorts have covered the research expenses associated with delivery of the injury prevention program.
The author wishes to acknowledge the support of Jimmie Spencer and Ken Hammell of the Canada West Ski Area Association for their support of this project and to thank Damien Moroney, Stacey Cleaveley, Ashlie DeJong, Steven Benjamin, Arielle Roberts, Myrna Watson, and Anne Pigeon for their insight and technical assistance.