21 effect upon flexion-extension angles due to this being the dominant motion (Ramakrishnan and. Kadaba, 1991). The canter is an asymmetrical gait where the ...
NOTTINGHAM TRENT UNIVERSITY
A Preliminary Investigation in to the Effects of a Short-term Massage Programme on Gait Parameter Variables, and Overall Gait Scored by a Panel, in Riding School Horses By Chloe Mabbutt
Dissertation submitted in partial fulfilment of the MRes Equine Performance degree
2015
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Abstract:
Musculoskeletal injuries have been reported to be the main contributor to the interruption or dismissal of a horse’s athletic career. The muscles are responsible for the production of forces involved in movement yet the muscles are often overlooked with regards to preventative maintenance and injury therapy and rehabilitation. Competition legal methods of preventing injury by improving performance are of particular interest. The use of massage therapy as part of a training programme is becoming increasingly popular. The beneficial effects of massage have been widely researched, though much of the research is on the immediate effects, and consistency between studies is lacking. This study was a preliminary investigation in to the effects of a short term massage programme on the gait parameters of riding school horses undergoing the same management and exercise routines. Methods: 15 clinically sound riding school horses at Nottingham Trent University of different breed, age and height were used in a controlled, blind study. The horses were divided in to three groups of five (A, B and C) ensuring a mixture of height, breed and age. Group A received a 10 minute massage each side on the caudal hind limb, once a week for three weeks. Group B received a 20 minute groom following the same procedure; and Group C received no treatment. Video gait analysis was conducted on weeks 0 and 4. Video number 3 of each gait on both reins was chosen for analysis by a sports analysis programme (Kinovea), and scoring by a panel of 16 equine students. Results: A significant increase in stride length symmetry and protraction symmetry was found for group A in the walk (P = 0.0475 and P = 0.0318 respectively). Significant differences were found for kinematic variables between the treatment and control groups in walk, trot and canter. A significant result was found for the panel analysis data for day 1 (P = 0.0055). Panel scoring positively correlated with stride length symmetry on day 1 in walk (P = 0.0058) and maximum hock flexion symmetry on day 2 in canter (P = 0.0473). Conclusions: It can be concluded that a short term massage programme to the proximal hind limb consistently improved gait symmetry within riding school horses compared to a sham treatment and control. An appropriate dosage level for particular results needs to be determined in order to effectively utilise massage within a training programme. Further studies analysing kinetic parameters alongside kinematic parameters will enable further conclusions to be drawn. i
Acknowledgements: Firstly I would like to thank my fellow course mates, for all their help and support, and my parents for their continued support in reaching my dream. Secondly I would like to thank the yard team for allowing me to perform my study at the yard; Jude and Ali for their services as riders, and the second year Equine students that acted as my panel. And lastly I would like to express extreme thanks to my supervisor Kelly; who has had to put up with me and help me with some sticky situations! Thank you so much for all your help and support.
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Contents Abstract: ................................................................................................................................................... i Acknowledgements: ................................................................................................................................ ii List of Figures: ........................................................................................................................................ v List of Tables: ......................................................................................................................................... v 1.0
Introduction:................................................................................................................................ 1
2.0
Review of Literature: .................................................................................................................. 4
2.1
Musculoskeletal Injuries within Equine Sports....................................................................... 4
2.1.1 2.2
Muscle anatomy and physiology of the hind limb .......................................................... 5
The Theory of Massage: ......................................................................................................... 6
2.2.1
Improvements in flexibility ............................................................................................. 6
2.2.2
Circulation, waste removal and muscle recovery ........................................................... 8
2.2.3
The role of massage in pain management ..................................................................... 11
2.2.4
Massage and stress reduction ........................................................................................ 12
2.2.5
Contraindications .......................................................................................................... 14
2.3
Massage and Performance: ................................................................................................... 16
2.3.1
Massage and performance - Human research ............................................................... 17
2.3.2
Massage and performance - Equine research ................................................................ 19
2.4
Analysing performance: ........................................................................................................ 20
2.4.1
Gait kinematics ............................................................................................................. 20
2.4.2
Methods of Analysis ..................................................................................................... 21
2.5
Rationale: .............................................................................................................................. 23
2.5.1
Current research limitations .......................................................................................... 23
2.5.2
Experimental design rationale ....................................................................................... 24
2.5.3
Kinovea ......................................................................................................................... 24
2.5.4
Analysis of Gait parameters .......................................................................................... 25
2.6 3.0
Aims and Objectives: ............................................................................................................ 26 Materials and Methods:............................................................................................................. 27
3.1
Horses: .................................................................................................................................. 27
3.2
Experimental Design:............................................................................................................ 28
3.2.1
Massage Technique ....................................................................................................... 29
3.2.2
Sham (Grooming) Treatment ........................................................................................ 30
3.2.3
Gait Analysis ................................................................................................................. 30
3.2.4
Video Analysis .............................................................................................................. 31
3.2.5
Panel Analysis ............................................................................................................... 34 iii
3.3 4.0
Statistical Analysis: ............................................................................................................... 34 Results:...................................................................................................................................... 36
4.1
Velocity:................................................................................................................................ 36
4.2 1: Investigate the impact of a short term massage programme, sham treatment programme and a control, on gait parameter variables of riding school horses ................................................... 36 4.2.1
Walk .............................................................................................................................. 36
4.2.2
Trot................................................................................................................................ 38
4.2.3
Canter ............................................................................................................................ 40
4.3 2: Investigate the impact on gait parameter variables of riding school horses before and after a short term massage programme, compared to a sham treatment and control. ............................... 42 4.3.1
Walk .............................................................................................................................. 42
4.3.2
Trot................................................................................................................................ 43
4.3.3
Canter ............................................................................................................................ 43
4.4 3: Investigate the impact of a short term massage programme, sham treatment programme and a control, on gait quality scored by a panel ................................................................................ 43 4.5 4: Investigate the impact of a short term massage programme, sham treatment programme and a control, on gait parameter variables and their correlation with gait quality scored by a panel, in riding school horses ...................................................................................................................... 45 5.0
Discussion: ................................................................................................................................ 46
5.1
Biomechanical Analysis – Measurement of all 3 gaits: ........................................................ 46
5.1.1
Changes in walk ............................................................................................................ 47
5.1.2
Changes in trot .............................................................................................................. 48
5.1.3
Changes in canter .......................................................................................................... 50
5.1.4
Conclusions of entire movement ................................................................................... 51
5.2
The muscles involved: .......................................................................................................... 52
5.3
Thermographic changes: ....................................................................................................... 53
5.4
Objective vs. Subjective Assessment: ................................................................................... 55
5.4.1
Validity of 2D video analysis........................................................................................ 56
5.5 Applications of the present study to the industry, limitations, and implications for further research: ............................................................................................................................................ 57 5.6
Conclusions: .......................................................................................................................... 61
References:............................................................................................................................................ 63 Appendix One: P Values ...................................................................................................................... 72 Appendix Two: R Code ........................................................................................................................ 75 Appendix Three: Raw Data ................................................................................................................ 153
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List of Figures: Figure 3.1 Diagram of hind limb muscles massaged during the trial....................................................30 Figure 3.2 Picture of gait analysis video capture during the study........................................................31 Figure 3.3 Angle measured to obtain maximum hock flexion measurement........................................32 Figure 3.4 Example of maximum flexion hock angle measurement on Kinovea..................................32 Figure 3.5 Example of stride length measurement on Kinovea.............................................................33 Figure 3.6 Example of hind limb protraction measurement on Kinovea...............................................33 Figure 4.1 Mean walk stride length symmetry values...........................................................................37 Figure 4.2 Mean walk protraction symmetry values..............................................................................37 Figure 4.3 Mean walk maximum hock flexion symmetry values..........................................................38 Figure 4.4 Mean trot stride length symmetry values.............................................................................39 Figure 4.5 Mean trot protraction symmetry values................................................................................39 Figure 4.6 Mean trot maximum hock flexion symmetry values............................................................40 Figure 4.7 Mean canter stride length symmetry values.........................................................................41 Figure 4.8 Mean canter protraction symmetry values............................................................................41 Figure 4.9 Mean canter maximum hock flexion symmetry values........................................................42 Figure 4.10 Mean walk panel scoring symmetry data...........................................................................44 Figure 4.11 Mean trot panel scoring symmetry data.............................................................................44 Figure 4.12 Mean canter panel scoring symmetry data.........................................................................45
List of Tables: Table 3.1 Study horse profiles...............................................................................................................28 Table 5.1 Hip thermal image temperature values for both sides, for each horse before and after the first treatment.........................................................................................................................................54
v
1.0 Introduction: A winning horse is something every top rider and trainer aims for. Many factors contribute to a horse reaching top level, conformation, bloodlines, training, the correct combination of horse and rider; however it is clear some horses are more naturally talented than others (Goer, 2000; Hodgson, McKeever and McGowan, 2013). Some horses fail to reach their expected potential while others reach levels never deemed possible; but one common factor between them, is that their musculoskeletal system is equal to approximately 60% of their total body weight (Booth 2009a), and when this system is responsible for movement, it is imperative to maintain full function to ensure maximum potential is reached, whilst limiting the risk of injury. Locomotion is the mechanical expression of energy transferred in to movement (Barrey, 1999). For a specific level of locomotion to be sustained, synergy between systems is required, which is then regulated by the nervous system (Barrey, 1999). The control of the musculoskeletal system is under delicate neurosensorial control, which allows each muscle is under individual control; but in order to obtain maximal movement patterns, they must all work together to support and propel the body. The movement of the body and limbs in particular rhythmic and automatic patterns create the definitions of certain gaits. The horse often suffers from injuries to its locomotor apparatus which ultimately affects movement and performance. In the case of sports horses, many performance problems occur due to human management errors and the environmental conditions that come with the sport (Barrey, 1999; Dyson, 2000). Large amounts of “wastage” occur in Thoroughbred racing, and approximately 53–68% is due to lameness (Jeffcott et al. 1982). The scale of this problem alongside competition regulations, preventing the use of many treatments for such injuries, has created the need for further research in to locomotion, including techniques for preventing lameness and improving performance that are competition legal. The muscles are responsible for the production of forces involved in movement yet the muscles are often overlooked with regards to preventative maintenance and injury therapy and
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rehabilitation (Booth 2009a). During training, the development and strengthening of muscles occurs, however overexertion caused by training beyond its fitness level, and overuse of underdeveloped muscles, can cause muscle damage and soreness and affect performance as a result (Smith et al. 1994; Booth 2009b). Signs of muscle damage and pain are not always evident, yet subclinical signs such as an increase in creatine kinase (CK) in the blood indicating muscle damage causes leakage of this protein (Goer, 2000). A recent study found 53/348 horses (15%) investigated for poor performance showed signs of muscle injury in response to a standardised exercise test (Martin et al. 2000); therefore protection of the muscles is vital in ensuring maximum potential is reached and maintained. During sub-maximal exercise, glycogen is utilised for energy and lactic acid as a by-product can accumulate in muscles resulting in fatigue and if not appropriately managed, damage to the muscle structure (Smith et al. 1994; Marlin and Nankervis, 2002; Booth 2009b; Scott and Swenson, 2009). When overuse or injury occurs, inflammation onsets initially, then after 48 hours, blood flow is reduced causing a reduction in oxygen and nutrients to the area; this causes tension and for the affected area to “splint” or contract (spasm), which results in additional pain and damage to other structures (Smith et al. 1994; Sullivan, Hill and Haussler, 2008; Booth, 2009b). This cycle must be broken in order to begin an appropriate healing process; and massage restores circulation and lymphatic drainage (Hemmings et al. 2000), muscle fibres and reduces muscle tightness (Wakeling et al. 2006) and reduces pain (Tiidus, 2000; Scott and Swenson, 2009). Specialisation in a particular discipline can also be detrimental and cause overuse injuries due to the same muscles and joints being used repeatedly, this particularly becomes a problem if the horse’s conformation is not suited for the task. Engagement of the hind limbs and collection of power is crucial at top level for all disciplines. However overuse can become apparent; for example jumpers may suffer from damage to the lumbosacral joint from constant power shifting during take-off and landing; and shoulder injuries due to concussion when landing; and dressage horses may suffer back and hind limb injuries from the preferred uphill gait (Booth, 2009b; Hill 2
and Crook, 2010). These local mini traumas often have a cumulative effect. Tension builds up in the hindquarters, lumbar and neck regions forming stress points and areas of restricted movement and power output, which ultimately affects performance and increases the risk of injury. Flexibility and tone must be restored to the muscle which can be accomplished by massage and stretching (Rose et al. 2009; Booth 2009b). Whilst massage is not a substitute for appropriate veterinary diagnosis and treatment, it could play an important role in injury prevention and maintenance, and as part of an appropriate training programme, and could increase longevity of career and improve performance. The aims of this study are to develop an understanding of the role of regular massage sessions in horses with no known health problems undergoing regular repetitive work by assessing both kinematic gait parameters and perceived improvement which is vital in terms of competitive success.
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2.0 Review of Literature: 2.1 Musculoskeletal Injuries within Equine Sports
Musculoskeletal injuries have been reported to be the main contributor to the end or disruption of a horse’s athletic career (Weishaupt et al. 2001) and the most common cause of poor performance in horses are subclinical disorders of the locomotor system (Morris and Seeherman, 1991). Reports have found lameness results in a $1 billion annual loss to the equine owning public in America (Pfau et al. 2007), and the prevalence of musculoskeletal injuries within 3 racing yards in Newmarket was 23-26% per year (Ramzan and Palmar, 2011); which causes large wastage problems and money losses. Jeffcott et al. (1982) found that lameness was the largest contributor to Thoroughbred racehorses less than 4 years old never reaching the racetrack; and only 34 out of 140 2-year-old Thoroughbreds did not show any signs of lameness. Although these statistics are not all based on muscle injuries, it can be assumed that a large majority of injuries stem from muscle injury or pain due to the muscles being responsible for controlling locomotion (Goer, 2000; Martin et al. 2000). Dressage, Show-jumping, Eventing and Racing are four of the biggest equine sports in the World, with Endurance also growing in popularity. Dressage requires the horse to balance itself and is an evaluation of controlled power and balance (Dyson, 2000); this causes a lot of gradual damage due to excessive movements resulting in inappropriate joint and limb angulations, poor management conditions and inappropriate utilisation of the immature skeletal system, and conformational genetics causing weakness and predisposition to injury (Dyson, 2000). Showjumpers experience huge forces on their tendons and ligaments which in turn pull on joints and muscles causing instability and damage (Dyson, 2000). Eventers undertake the dressage and show jumping phases with the added cross country element. All three phases require different skills, meaning they are often not always suitably prepared for all 3 three phases. The physical demands of the cross country element add fatigue in to the equation; therefore if a horse is not in peak condition, then muscular damage may onset and repetitive injuries can occur (Dyson, 2000). 4
With this information being known, competition legal methods of prevention and rehabilitation are of great importance. In modern competition the difference between winning and losing can be as little as a few milliseconds or points of a percentage; therefore methods of preventing injury by improving performance are of particular interest (Guest and Cunliffe, 2014). 2.1.1
Muscle anatomy and physiology of the hind limb
Equine skeletal muscle is highly developed and has considerable potential to adapt to stimulus such as exercise training (Back and Clayton, 2013, p.127). The muscles of the proximal hind limb account for 42-53% of a horse’s total body mass and are required primarily for propulsion (Back and Clayton, 2013, p.127). They have a large cross sectional area with long fibres that extend over the length of the muscle. Equine gaits consist of a stretch-shortening cycle controlled by muscular contractions (Birch et al. 2013). Muscle is made up of 90% myofibres, with nerves, blood vessels, fat and connective tissue making up the remaining 10% (Birch et al. 2013). Different fibre types are specialised to different functions such as sprint or endurance, anaerobic or aerobic exercise, however all fibre types require energy for contractions which create movement (Birch et al. 2013). This energy is used to move the horse’s limbs in patterns established for each gait; however anatomical problems such as damage to the muscle, prevent appropriate movement. Muscle contractions occur by the control of motor nerves. One nerve can supply for precise movements as little as 10 fibres, where less precision and more power is required up to 2000 fibres can be controlled by one nerve (Marlin and Nankervis, 2002, p.21). Baseline stimulation of the nerves to maintain muscular posture is known as tone and damage to the nerves controlling this can lead to muscle atrophy and a decrease in performance (Marlin and Nankervis, 2002 p.21). Techniques such as massage may be of benefit as an additional training tool to aid in maximal function of muscle, and to assist in the healing of damaged muscles.
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2.2 The Theory of Massage:
Massage therapy is defined as manipulation of the skin and underlying soft tissue for therapeutic purposes either manually via rubbing, kneading, or tapping, or via mechanical vibration using a machine (Hemmings, 2001; Haussler, 2009). Massage techniques include many methods such as Swedish massage, sports massage, trigger point therapy, myofascial release and acupressure and it is one of the oldest therapeutic treatment methods originating from 300–400 years BC (Haussler, 2009). Massage is used widely for human and veterinary purposes for both its physiological and psychological effects, however much of the evidence is anecdotal, and in terms of human use, psychological benefits could manifest as perceived physiological benefits (Hemmings et al. 2000; Wilson, 2002). Massage therapy is used regularly as part of a training programme in human athletes, and its therapeutic use within the general population has also grown in recent years (Brummitt, 2008; Scott and Swenson, 2009). The increase in the use of massage therapy in humans is largely down to anecdotal evidence improving perceptions, and observations of improved performance (Tiidus, 2000). Reported benefits of massage range from reduced muscle tension and soreness, improved range of motion, and a reduction in neurologic excitability; to a decrease in resting heart rate, increased pain threshold and an increased sense of well-being (McBride, Hemmings and Robinson, 2004; Haussler, 2009; Scott and Swenson, 2009). It has also been reported that therapeutic massage enhances blood flow to the muscles and assists in lactate clearance alongside reducing creatinine kinase levels, which in turn aids in producing improved performance and recovery (Best et al. 2008; Scott and Swenson, 2009); however there is a lot of conflicting research, particularly when it comes to its role in performance enhancement. 2.2.1
Improvements in flexibility
Massage increases the elasticity of intramuscular connective tissue and maintains muscle flexibility (Hemmings et al. 2000; Hill and Crook, 2010). Massage is used to improve muscle 6
tone by relaxing the cutaneous mechanoreceptors and pressure receptors (Sullivan et al. 2008; Salter et al. 2011); as such, the muscle relaxes and becomes more controlled which improves muscle flexibility and joint range of movement (Hill and Crook 2010). There is some evidence that massage reduces sympathetic activity in the muscles and that causes a reduced Hoffman’s reflex response, a measure of muscle tone, in calf muscle during but not immediately postmassage, indicating short term muscle relaxation; however, evidence of long term relaxation effect has not been studied (Tiidus, 2000). Barlow et al. (2004) found no immediate improvements of hamstring flexibility from a “reach score” in 11 active young men following 15minutes of massage compared to before treatment. However they did conclude those who started with a pre-test reach score of less than 15cm had a greater percentage improvement than those with a pre-test reach score over 15cm. Suggesting only compromised flexibility may be improved with massage, therefore they suggested further research with a larger sampling size with varying degrees of flexibility. However Crosman, Chateauvert and Weisberg (1984) found the hamstring flexibility of 34 random female subjects between 18 and 35 years old, improved significantly following a 9- 12 minute massage to one of their legs compared to the other. However this improved range of motion returned to pretreatment levels in almost all subjects when measured again 7 days post treatment. Little and Williams (2006) found dynamic stretching prior to exercise tests had the greatest improvement on performance compared to static and no-stretching. This study evaluated the effects of the stretching after a warm up period, followed by a further warm up period. This extra muscular activity prior to investigation may have shown a more realistic and valid result due to following appropriate pre-competition procedures. The results suggest dynamic stretching is more effective than static stretching due to greater muscular activity which have been associated with massage (Little and Williams, 2006). In horses Hill and Crook (2010) found massage increased passive and active hind limb protraction compared to a control group with a cross over design following a 7 day washout period. However it was not stated when the data was collected following the massage. Whereas Rose et al. (2009) 7
found stretching had no significant effect on stride length despite a number of significant differences being found in joint ROM between treatments in the shoulder, stifle and hock. Research is positive in terms of validating the benefits of massage on flexibility and range of motion, but pre-treatment state of the participants needs to be considered when interpreting results. 2.2.2
Circulation, waste removal and muscle recovery
Muscle fatigue is caused by successive muscular contractions; however muscular contractions are required for movement. The inability to sustain a required force output, muscle tremors, overextension, and localised trauma already present; are all causes of muscle fatigue and injury. If a muscle is unable to function appropriately, performance is limited. The restriction of blood flow to muscles during activity is a cause of fatigue due to the inability to deliver sufficient amounts of oxygen, and remove waste products which inhibit long term function and lead to muscle damage (Mori et al. 2004). The lymphatic system, unlike the circulatory system, has no “pump” associated with it in which to assist the movement of fluids around the body. The lymph vessels run alongside the veins to gain stimulation for movement. Massaging following lymphatic flow increases drainage and therefore reduces excess fluid in the tissue and allows for appropriate fluids to enter the muscle (Booth 2009a). Massage affects circulation due to the pressure applied mechanically assisting the venous blood flow, and therefore increases the efficiency of removing waste products from the body (Booth, 2009a). This increase in blood flow also helps dilate the blood vessels, which is highly beneficial during exercise. The affect of massage on circulation in the equine has limited research. However Salter et al. (2011) found massage increased cutaneous temperatures (1.0 ± 0.3°C) in the horse significantly and continued to significantly increase cutaneous temperature by 1 hour post massage ( 2.2 ± .4°C). Rectal temperature was taken in the horse pre and post massage, and no significant changes were found. Their study was conducted in the same area for each horse with ambient temperature monitored throughout; however ambient temperature did significantly 8
increase between 5 minutes post massage and 1 hour post massage. Therefore the results 1 hour post massage need further investigation, particularly when results could be applied to the industry with use warming up prior to competition. The result of enhanced blood flow is an improvement in the levels of oxygen and nutrients supplied to the tissues via arterial blood, improving healing abilities and performance; and the enhancement of waste products and toxin removal via venous blood (Hemmings, 2001; Mori et al. 2004; Booth 2009a; Scott and Swenson, 2009; Salter et al. 2011). Mori et al. (2004) found sports massage instantly after exercise increased muscle blood volume compared to rest and that participants felt less fatigued after massage compared to rest. However Wiltshire et al. (2010) found opposite findings, that massage had a negative effect on blood flow and lactate removal after exercise; but Wiltshire et al. (2010) monitored blood flow during massage, whereas Mori et al. (2004) monitored blood flow during the exercise tasks. This could explain the findings by Wiltshire et al. (2010) due to the massage compressions temporarily removing the blood from the area, followed by large blood return to the area once released, as noticed by Mori et al. (2004), (Booth 2009a). Due to this enhanced drainage and blood flow effect, massage has been anecdotally reported to enhance muscle recovery from exercise. Massage therapy has been reported to positively influence muscle healing following high intensity exercise by controlling factors associated with muscle repair. The physical symptoms associated with muscle damage include muscle weakness and stiffness and can potentially lead to delayed onset muscle soreness (DOMS) (Smith et al. 1994; Hemmings, 2001; Wilson, 2002) which affects performance. The effect of massage on muscle damage and repair have not been extensively researched due to limitations of experimental designs, many researchers focusing on the effects on massage on blood flow during massage followed by a performance test rather than long term muscle physiological changes (Tiidus, 2000). Many researchers also do not consider the effect of compression followed by dilation on repair and focus primarily on the immediate effect. However Wilson (2002) used ultrasound to
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monitor muscle diameter before and after massage and found the muscle belly increased by 14% following massage, suggesting a dilation effect. The inflammatory response and white blood cell invasion of muscle post exercise is vital to muscle protection and healing, any factors inhibiting this process lead to a lack of muscle repair, while overstimulation leads to further damage via inflammation (Tiidus, 2000). The use of massage to aid in recovery after exercise is yet to be established; however Arroyo-Morales et al. (2008) studied the effects of massage on a variety of physiological parameters over the entire body after high intensity exercise. In the study, 62 people were used to complete a high intensity cycling exercise programme after a standardised warm up. Baseline levels of heart rate and blood pressure were recorded for each subject prior to the test. People were divided in to 2 groups postexercise and were treated with either massage or a sham therapy. It was found after the exercise test, all subjects had a significant decrease in heart rate variability and diastolic blood pressure (BP) compared with baseline; but after the recovery period, the massage group recovered to preexercise levels whereas the sham group had significantly lower levels compared to pre-exercise and a lower parasympathetic (high frequency- HF) value associated with heart rate variability. Suggesting the massage allowed for appropriate recovery of the autonomic nervous system by assisting the physiological parameters to return to pre-exercise levels, whereas the placebo group could not recover appropriately within the time without further intervention; indicating an increased parasympathetic withdrawal (Arroyo-Morales et al. 2008). Lowering of diastolic BP and in a short time period can give rise to symptoms such as dizziness which can affect performance, and low HF values have been associated with cardiac malfunction, particularly in athletes; therefore these results could be highly significant for athletes competing multiple times within a set period of time (Tiidus, 2000). They also found a reduction in the level of white blood cells post massage in the muscles, agreeing with the findings by Smith et al. (1994), which has been found to aid in the prevention of DOMS. Butterfield et al. (2009) also found 30minutes of massage immediately after exercise enhanced recovery. The process of exercise-massage was repeated for 4 days on rabbits and after 4 days 10
muscle damage and muscle wet weight were reduced compared to the exercise-rest group and the exercise-massage group recovered 60% muscle strength compared to 14% in the exercise-rest group. Indicating massage not only aided in muscle recovery, but improved performance (Scott and Swenson, 2009). However the reduction in muscle wet weight does not match the findings by Wilson (2002) that found an increase in muscle belly diameter following massage, which was suggested to be an increase in fluids in the muscle. This highlights the importance of researching both the immediate effects of massage, and the longer term effects. Although massage has conflicting evidence as to its use in post-exercise recovery and muscle repair; two studies have reported that augmented soft tissue mobilisation and massage have caused an increase in fibroblast presence in injured tendons in rodents (Davidson et al. 1997; Gehlson, Ganion and Helfst, 1999). Fibroblasts are essential in tendon healing, meaning that massage may improve the rate and quality of healing in damaged tendons and be beneficial in reducing the symptoms of tendonitis (Tiidus, 2000). However no specific studies have been performed in horses on the affect of massage on tendon healing and further studies need to be performed using clinical situations to validate these preliminary findings. 2.2.3
The role of massage in pain management
Massage has been found to reduce the onset of DOMS and therefore the pain and stiffness associated with it (Smith et al. 1994; Hemmings et al. 2000; Tiidus, 2000; Hemmings, 2001; Brummitt, 2008; Scott and Swenson, 2009). Massage has also been found to reduce swelling and pain from surgery or injury, when medical permission is sought, primarily due to the movement of fluids; however in horses pain is more difficult to evaluate due to the lack of clear scientifically validated signs of pain (Scott and Swenson, 2009). Sullivan et al. (2008) studied the effects of massage and chiropractic treatments and phenylbutazone compared to a control on spinal mechanical nociceptive thresholds (MNTs) in 38 horses and found massage increased spinal mechanical nociceptive thresholds by 12% after 7 days, chiropractic (27%) and phenylbutazone (8%), compared to controls (
