SPACE GUIDE TO WINTER SPORTS – SKIINGEducation
Alpine skiing is known to be a sport with an above-average risk of injury
The most frequently injured body parts are the knee (35.6 %), the lower leg (11.5 %), with a rupture of the anterior cruciate ligament (ACL) being the most frequent diagnosis (13.6 % of all injuries). Other frequently injured body parts are the lower back, pelvis, sacrum (11.5 %), the hand, ﬁnger and thumb (8.9 %), as well as the shoulder (6.8 %).
It is known that nearly all injuries occur while the skier is turning (80 %) or landing (19 %). Injuries to the head and upper body mainly result from crashes (96 %), while the majority of knee injuries (83 %) occur while the skier was still skiing.
Individual Related Risks
A number of factors are highlighted in the research as potentially having a link to injury:
- Fatigue within a session
- Insufficient physical fitness
- Technical mistakes
An indirect indication that fatigue and general physical ﬁtness play an important role in injury might be found in the observation that most injuries occur towards the end of a days skiing when fatigue arguably becomes evident; however, a higher injury rate towards the end of the day or session could also be explained by the increased risk-taking behaviour due to confidence increasing during the day.
Snow Related Risks
Three different snow-related risk factors have been reported in the literature: ‘aggressive snow conditions’, ‘changing snow conditions’, ‘too bumpy/too smooth snow surface’.
With regard to ‘aggressive snow conditions’, snow temperature, snow density, and snow microstructure are known to be factors that determine the response of the snow surface. In particular cold temperatures, low humidity and artiﬁcial snow production have been suggested to be associated with aggressive snow conditions. The fundamental phenomenon of artiﬁcial snow is the small snow grain size, high snow density, and the strong bonding between neighbouring snow grains (microstructure), resulting in aggressive ski–snow interaction. Furthermore, ‘changing snow conditions’ within the same run might expose skiers to additional risk since alterations in the snow challenge the skier in adapting their technique and setting up their equipment adequately.
So with this knowledge onboard we will look tomorrow at what things can be done to prevent or plan for these conditions….
#Physiotherapy #Edinburgh #BestPractice #SportsInjuries #Ski #Snowboard #Prevention
With yesterdays look at which areas of the body get injured on the slopes and what the potential risk factors are we want today to address what can be done to mitigate these and other risks..
Individual Risk Factors
Firstly we want to expand slightly on the individual factors that we highlighted yesterday and bring to your attention to other variables which the literature surrounding alpine injuries raise. These are:
- Adverse crash behaviour (i.e. knowing injury mechanisms)
- Insufficient adaptability (i.e lacking the technical skill for a chosen run)
- Low peripheral body temperature
- Poor mental skills (i.e lack of focus, concentration)
- Pre-injury (i.e. having a history of a specific injury or arriving carrying an injury)
With regard to Adverese Crash Behaviour awareness of how injuries occur and the mechanisms involved has been shown to reduce serious knee sprains in patrollers and instructors by about 62% (Ettlinger et al 1995). The program laid out a number of phases but importantly contained simple instructions for the participants to follow: 1) Dont straighten your legs when you fall, keep your knees flexed. 2) Dont try and get up till until you have stopped sliding – When your down, stay down. 3) Dont land on your hand. 4) Dont jump unless you know how or where to land. Land on both feet and with knees bent.
A number of other potentially dangerous positions were also highlighted such as 1) Skier off balance to the rear, 2) all weight on the inside edge of downhill ski tail, 3) uphill ski unweighted, 4) hips below knees, 5) upper body generally facing downhill ski, 6) uphill arm back. The following strategy highlighted in the paper addresses five of the six elements of the injury mechanism: 1) Arms forward, 2) Skis together 3) hands over skis
Low peripheral body temperature is commonly caused by body heat transfer to the environment causing varying levels of hypothermia which can impede decision making. Advice is to wear the appropriate clothing and when you are aware that you feel very cold take a break and warm up again.
Pre-injury. With regard to the risk factor ‘pre-injury’, meaningful screening methods identifying individuals at high risk of (re)injury can help to develop individualized prevention and/or return-to-sport training programs and are therefore essential tools for controlling the risk of (re)injury and safely returning to sport. Assessing landing mechanics, sie cutting mechanics and lower limb strength and addressing any insufficiencies found can go some way to preventing injury or at least improving performance. It is here that our expert physiotherapists can first have a real impactful role. These assessments can be hugely beneficial to those who either have never had an injury, have a history of injury, or for those that have maybe recovered from surgery and are hoping to return to the slopes.
Fatigue within a session and insufficient physical fitness. In this context, a superior physical ﬁtness level might also be a reasonable prevention measure to put in place weeks or months prior to returning to the slopes or pre-competition. With respect to speciﬁc physical ﬁtness factors, a recent study provided evidence suggesting that training of trunk strength and avoidance of trunk strength imbalances are key measures for the prevention of ACL injuries in alpine ski racing.
To avoid ‘technical mistakes’ while skiing, sport speciﬁc balance or neuromuscular training might be effective prevention measures since wearing ski boots is known to additionally challenge the dynamic task of maintaining balance. Recent studies have shown the ability of neuromuscular training programs to reduce the risk of ACL injuries in sports other than alpine ski racing.
With injury prevention in mind, why not book in with our #physiotherapists to assess your legs and trunk strength and to help and advise on a program to strengthen both key areas and improve your neuromuscular control.
Tomorrow we will look at some exercise programming that you can start in your own home….
#ExpertsInSport #ExpertsInSPACE #Physiotherapy #SkiPhysio #Prevention #ACL
Ettlinger et al (1995) A method to help reduce the risk of serious knee sprains incurred in alpine skiing. American Journal of Sports Medicine, 23 (5), 531 – 537
In today’s blog post we will take a closer look at the physical demands of skiing and what areas are worth targeting pre-holiday.
Skiing requires a variety of qualities for both success and injury prevention. Several physiological and physical variables, such as muscle strength, aerobic and anaerobic power, coordination, ﬂexibility and the ability to sustain stress, are required.
Irrespective of gender, trunk strength seems to be a critical factor for preventing injuries in skiers of all levels and especially in competitive skiers. The leg and core muscles control the ski stance, minimising excessive knee forces and thus reducing potentially risky knee positions. Good trunk strength and balance are equally important for maintaining a central position on the skis to prevent critical injury.
Knowing that trunk strength is a critical factor in preventing injuries, targeted preventative training programmes must include speciﬁc core strength training. Next to muscle strength, neuromuscular control deﬁcits have been documented as factors contributing to ACL injuries. Skiers have to regularly absorb sudden forces acting on the body so while static holding exercises may build strength, exercises which challenge postural stability are essential.
We have layed out below a few very simple starter exercises that you can try at home. They begin with a simple hold then there are progressions which challenge control more and finally have weight added to start building some strength. These are only a small selection of the many that we regularly prescribe to our snow sports patients and we highly recommend coming into see us to make sure the correct ones for you are prescribed.
Begin on the floor and move to a more unstable surface.
Hold the position for 30’s plus.
Repeat 3 -4 x
Begin with short leg/bent knee version before moving onto straight leg then finally onto an unstable surface.
Hold for 30’s plus and repeat both sides 3-4 x
Begin with double leg squat before progressing to split squat then increase stability challenge by raising back leg.
Hold positions for 30’s plus and repeat 4-5 x.
Begin with having bodyweight on bent leg. Progress to sliding other leg out to the side on a towel and repeating. Progress to holding weight then finally onto holding weight and sliding
Hold each exercise for 30 seconds plus and repeat 4- 5 x
#ExpertsInSport #ExpertsInSPACE #Phsyiotherapy #SkiPhysio #Prevention #Edinburgh #Ski
Following on from our look at the type of injuries that can be picked up on the slopes we wanted to focus this week on a few specific body parts.
We will start this second week with a look at Anterior Cruciate Ligament (ACL) injuries.
ACL injury is by far the most common specific injury in ski racing. In an early attempt to characterize ACL injury, Ellman et al (1989) surveyed 600 alpine ski racers in Vermont and found that 33 of 135 (24.4%) male racer respondents had a history of knee injuries, with 4 of those indicating an ACL injury (2.9%). Of the 61 female ski racer respondents, 23 indicated a previous knee injury (37.7%) and 11 of those were an ACL injury (18%). Stevenson et al (1998) reported a similar prevalence of ACL injuries between recreational alpine skiers and alpine ski racers. They also reported a 3.1 times increased likelihood for ACL injury in females compared with males.
Three mechanisms of ACL injury have been identified (Berre et al,2011) in video analysis: slip-catch (10 of 20 injuries), landing back-weighted (4 of 20 injuries), and dynamic snowplow (3 of 20 injuries).
The slip-catch mechanism occurs while turning when the skier becomes out of balance backwards and inward, which causes the weight to shift completely to the inner ski, allowing the outer ski to drift away from the centre of mass. When the skier attempts to extend the leg and reestablish grip with the outer ski, it abruptly catches the snow surface and forces the knee into flexion, internal rotation, and valgus.
The dynamic snowplow mechanism occurs when the skier is out of balance backward with the weight unequally distributed between the skis. Similar to the slip-catch mechanism, the unweighted ski drifts away from the center of mass. The loaded ski then moves from the outside edge to the inside edge, forcing the knee into internal rotation and valgus.
The landing back-weighted mechanism occurs when the skier is balanced with a centre of gravity posterior to neutral after a jump, landing on the ski tails with nearly extended knees, resulting in tibiofemoral compression with a boot-induced and quadriceps induced anterior drawer.
ACL ruptures, in particular, can occur when the ski acts as a lever to generate high forces and torque at the knee. Many skiers rank the ability of a binding to prevent inadvertent release higher in importance than its ability to prevent injury. In one study, 73 % of racers who had ACL ruptures had bindings that failed to release. Skiers may intentionally adjust their bindings too tightly in an effort to prevent inadvertent binding release. There are select instances in which maximum bending and torsional loads are exerted on the leg after binding release, resulting in post-release injuries; however, inadvertent binding release is felt to account for less than 5% of all skiing injuries, while over-tightened bindings may contribute to as much as 30% to 40% of injuries.
The prevention strategies for the ACL are very similar to what we have highlighted before.
- Having the appropriate strength and endurance in the lower legs and trunk. Make sure any exercise routine that you undertake includes exercises such as those shown above in the Day 3 post. For further guidance on exercise selection please make an appointment to come see our #physiotherapists.
- Making sure that your equipment is maintained and that if you are hiring you seek advice on fitting properly and check the bindings thoroughly
- Educate yourself on the potential risk mechanisms and if you have had time away from the slopes that you consider getting a refresher lesson
- Stick to runs that are appropriate for your skill level and be aware of changing weather and snow conditions.
If you do unfortunately fall foul to an #ACL injury on the slopes we will use our next blog to highlight the fantastic work SPACE director and leading surgeon Professor Gordon Mackay is doing using his Internal Brace.
If you have any queries about the mechanisms involved in these injuries or are looking to spend time on prevention strategies come see us in the West End of Edinburgh.
#ExpertsInSport #ExpertsInSPACE #SkiPhysio #ACL #Internalbrace #Surgery #EdinburghPhysio #Injuries
Bere T, Flørenes TW, Krosshaug T, et al. Mechanisms of anterior cruciate ligament injury in World Cup alpine skiing: a systematic video analysis of 20 cases. Am J Sports Med. 2011;39:1421-1429.
Ellman BR, Holmes EM 3rd, Jordan J, McCarty P. Cruciate ligament injuries in female alpine ski racers. In: Johnson RJ, Mote CD Jr, Binet M-H, eds. Ski Trauma and Safety: Seventh International Symposium, ASTM STP 1022. Philadelphia, PA: ASTM; 1989:105-111
Stevenson H, Webster J, Johnson R, Beynnon B. Gender differences in knee injury epidemiology among competitive alpine ski racers. Iowa Orthop J. 1998;18:64-66.
So the skiing holiday hasn’t quite gone to plan! You have unfortunately suffered a knee injury and are now returning to the UK and wondering what your next step should be.
We would recommend getting in ASAP to see our highly trained expert physiotherapist for an initial assessment. What makes SPACE unique in the private clinic setting is our in-house leading orthopaedic surgeon Professor Gordon Mackay. This allows us to directly refer you for a consultation and discuss closely what our clinical impression is and what the agreed plan moving forward should be, all done under one roof. In SPACE you are in expert hands.
Professor Mackay has developed over a number of years cutting edge surgical techniques and materials to improve patient outcomes. In his own words
Some forty years since the importance of the ACL was recognised in terms of knee stability, surgeons have sought a way to restore knee stability kinematics – and ultimately function – after injury.
Initial attempts to repair the damaged cruciate ligament directly end-to-end were disappointing with only a third restoring satisfactory function, although at this time material technology was poor and a prolonged period of immobilisation was required to protect the repair, which often resulted in permanent dysfunction and the requirement for open surgery. Our understanding of the anatomy of the ACL was also relatively poor.
Pioneering surgeons such as John Fagan and Dr Steadman explored the possibility of microfracture to facilitate healing as well as augmentation. It was found that using autologous graft tissue such as hamstring tissue or patellar tendon restores stability. It was assumed that the environment of the knee itself was too hostile, possibly as a result of the synovial fluid to facilitate healing.
So, for the last thirty years we have focused on using effectively dead tissue harvested from other areas in the body to replace the cruciate ligament. This has involved drilling through bone and securing soft tissues, but unfortunately this has failed to prevent arthritic change, which has long been associated with ongoing instability.
Biological advancements and an increased understanding of cellular function have identified the importance of nerve cells within the cruciate ligament called mechanoreceptors. These receptors identify stretch and fire hamstrings automatically to protect the knee and ultimately the cruciate ligament. Unfortunately when these are removed surgically this reflex is lost permanently and never fully recovers.
Interestingly, the medial ligament, which continued to be managed conservatively, was considered capable of healing even if the tissues were attenuated, because of the inherent scaffold. Animal studies went on to show that if a scaffold could be positioned appropriately then cruciate ligament in animal model could indeed heal.
This was transferred to the clinical setting using the InternalBrace and our understanding of anatomical graft placement. Material technology provided an inert construct tested within the body, including intra-articular environments. Unlike failed synthetic grafts in the past, the InternalBrace was only 2mm in diameter, causing minimal iatrogenic injury, and did not attempt to replace the cruciate ligament itself.
It provided temporary stability and a scaffold for healing but the outcome was entirely dependent on this healing process. Remarkably early studies have shown that after twelve weeks, not only is there radiological evidence of ACL healing but functional testing has shown that athletes have been able to replicate pre-injury scores at twelve weeks and in certain cases exceed their pre-injury score. This function and the restoration of normal kinematics could not be achieved with a standard ACL reconstruction as commonly accepted.
This opens a whole new horizon for knee surgeons and their patients. Long-term follow up is still desirable, but patients have been followed up now to in excess of four years with no evidence of knee detrimental reaction. If the InternalBrace is excessively tightened there is some crepe within the fibre tape itself measuring up to 3mm if loaded at 300 newtons. There also is a potential for some modest slippage past the swivel lock fixation in the tibia which could result in compensatory rebalancing. The knee however, is always tensioned gently in full extension to prevent any over constraint.
Patients have witnessed much improved outcomes, less pain, less swelling and less muscle wasting, plus an early return to work or sport. Most significantly, ACL repair and InternalBracing does not in any way preclude a standard ACL reconstruction being carried out if the soft tissues fail to heal adequately. On the first thirty patients followed through, only one patient has actually required a definitive ACL reconstruction in the traditional manner.
For more information about Professor Mackay and the Internal Brace please go to https://www.mackayclinic.co.uk/
If ever there was a better example of the amazing impact the Internal Brace can have on skiers look no further than this case study on former Olympic Skier Alain Baxter.
#ExpertsInSport #ExpertsInSPACE #InternalBrace #Ski #ACL #Edinburgh