Abstract
This study examined the impact of an exercise program of myofascial release exercises and head/neck postural re-education to correct forward head posture on golf swing kinematics. Both control and experimental group participants struck five 6 iron shots into a golf net whilst 3D kinematic data were collected upon their swing movements. Participants in the experimental group then completed 8 weeks of myofascial release exercises using spikey balls and head/neck postural re-education before both groups were retested. Significant differences in pre to post change scores were found between groups in cervical flexion with reduced cervical flexion at address (p=.03) in the experimental group and an improved torso-head alignment in the sagittal plane (p=.02). Evident changes were also observed in head movement during the swing, but not in torso movement. Considerable intra-individual variation of response was observed and this is discussed in the context of coaching and movement coordination.
Introduction
Golf, as a sporting pursuit, requires the golfer to undertake a range of physically demanding movement patterns throughout the course of play (Hume et al., 2005). According to Smith (2010), the dynamics of the golf swing are to a large extent dictated by the anatomical and physiological make-up of the body with swing types usually governed by what the golfer can and cannot do with their bodies during static and dynamic positioning. This suggests the possibility of physical training interventions influencing swing dynamics and kinematics. Existing work examining physical training interventions in golf primarily focus on aspects relating to muscular strength, flexibility, plyometrics and body conditioning (Bull and Bridge, 2012). Massion (1992) suggests that careful consideration should be given to factors that can impact on static posture in anticipation of movement and dynamic postural control, both of which will affect the movement itself.
Most golf literature focuses on spine positioning when describing upper body posture, (e.g. Geisler, 2001a, Hume et al., 2005, Maddalozzo, 1987), with little reference if any directed to the role of the neck and head. To my knowledge, little scientific research has been published on ideal head orientation and position and the impact that postural abnormalities around the neck may have on golf posture as well the impact forward head posture has on golf swing mechanics. Forward head posture (FHP) has been shown to influence both proprioception, Lee et al. (2014) and shoulder function both in range of motion and scapula control as well as postural changes in both upper thoracic and cervical spine (Braun and Amundson, 1989). FHP as defined by Lee et al. (2014 p1741) is when “the head is anterior to a vertical line through the centre of gravity” and is best viewed and assessed in the sagittal plane (Salahzadeh et al., 2014) typically by physiotherapist using the plumb line method (de Oliveira et al. (2012). Often, photographs are taken as pictorial references to relate to and in the absence of advanced tracking and scanning systems provide the most popular way for physiotherapists to assess forward head, Harman et al. (2005) and Fortin et al. (2011) although this does not make this approach completely reliable as it still requires interpretation which can lead to subjective error.
FHP is one of the most commonly noted abnormal postures (Griegel-Morris et al., 1992) and is a position commonly adopted by office workers and involves a combination of lower cervical flexion, upper cervical extension head tilt as well as rounded shoulders (scapular protraction and elevation, Ariens et al. (2000). This combination of change and the prevalence of FHP in society and everyday activities results in it taking some time to correct FHP (Gore et al., 1986). The weight of the head is more like a bowling ball than a golf ball, so holding it forward, out of alignment, puts a strain on your neck and upper back muscles resulting in muscle fatigue (Mayo, 2000). This forward translation of the head and a subsequent kyphotic posture of the cervical spine has been found to increase stress on the cervical vertebrae by 6-10 times (Harrison et al., 2001).
Roddey et al. (2002) investigated the short term effect of a daily pectoralis major stretching program on the short term resting static scapular protraction distance from the spine. The study found that scapular protraction distance was significantly reduced in the moderate FHP group but no significant change in either a control or mild FHP group. Lewis et al., (2005), believe that these findings suggest that in asymptomatic participants with moderate FHP a pectoralis major stretching program will decrease static scapular protraction however, what is not known is if this had an effect on the range of movement of the shoulder as this was not reported by Roddey et al. (2002).
Sahrmann (2001) and Scovazzo et al. (1991) believe that exercise interventions aimed at strengthening weak musculature and stretching tight, over developed musculature are thought to improve FHP. Studies by Lynch et al. (2010), Lee et al. (2014), Harman et al. (2005) and
Thigpen et al. (2010) have attempted to correct FHP through a training protocol involving flexibility and strength exercises whereas Lee et al. (2014) found FHP can reduce head proprioception. The treatment of FHP most often centres on stretching the shortened pectoralis minor, upper trapezius and levator scapula alongside postural re-education (Roddey et al. 2002, Wang et al. 1999, Harman et al.2005).
Myofascial release is an advanced massage technique widely used in assessing and stretching soft tissues and targeting myofascial trigger points (Johnson, 2009, Healey et al., 2014, MacDonald et al., 2013). Johnson (2009) adds that people who maintain static postures or remain in flexed postures for periods of time and/or have associated neck and shoulder postural abnormalities and pain due to increased muscle tension may benefit from soft tissue release. Johnson (2009) continues by stating that soft tissue release is a way of targeting the less pliable part of the muscle where there is palpable tightness, often where static stretches have limited benefit. As well as the human hand, elbow and thumb, various tools have been used for people to self-massage soft tissue and myofascial trigger points, objects such as foam rollers (Houglum, 2010, Healey et al., 2014, MacDonald et al., 2013) and spiky balls (Oswald et al., 2007).
The attainment of the optimal pre-stroke posture is achieved through a good starting position (Thériault and Lachance, 1998); which according to Geisler (2001a), should align the golfer properly with the target, establish dynamic and static balance and be in a sound biomechanical position. Thériault and Lachance (1998) warn that the potentially harmful effects of anomalies of posture or technique may cause excessive stress on the structures of the spine through over tension, over rotation or put golfers at risk of shoulder injuries. Booth (2005), in providing a physiotherapy overview of a professional golfer, found that prolonged playing and practice had led to postural adaptations due to the excessive time spent in ‘golf posture’. Booth (2005) explained how this was manifested in a ‘poking chin’ (colloquial definition for forward head posture) which was prevalent in both the golfer’s anatomical and golf posture, as such FHP could have an impact on a golfer’s technical performance and swing kinematics.
Given the prevalence of FHP in society (Griegel-Morris et al., 1992) and that in the golf swing a golfer is in a position that further encourages a forward translation of the head the aim of the current study is to explore the effects of a soft-tissue release intervention and postural re- education designed to reduce FHP on golf swing kinematics.
Method Participants
Skilled golfers (category one – handicap <5) were chosen as the sample population for the study as they have been shown to have a reduced variability in their swing mechanics and would therefore produce more reliable swing mechanics increasing the internal validity of the results. Participants were recruited from the University’s student population of golfers. Individuals expressing an interest in the study were given written information about the study covering its purpose and commitment required from them should they participate. They were also given the opportunity to question the investigators about the study. Thirty-two right handed participants who had volunteered to participate in the study and provided written informed consent prior to participation. After the initial 3D swing data collection participants were paired for forward head bend values, as assessed at golf address and then one of each pair was randomly assigned to either a Control (n=16) or Experimental group (n=16). Forward head bend was measured as the angle between the local anatomical z-axis of the head and the global z-axis, where the global axis is defined as being vertical with respect to the ground and the plane formed by the x & y axes. Mean group values for head bend at address were Control: 61±8° and Experimental 64±8° (t33=.9, p=.39), whereas, according to GBD software values for forward head bend typically golfers with appropriate address posture values would range from 45-60°. The Control group had a mean handicap of 3.1 ± 2.1 shots and mean age of 19.2 years ± 1.5 years. In the Experimental group, two members were professional golfers, and the handicap of the remaining participants was 2.3 ± 3.3 shots (2 professionals excluded) and mean age was 22.2 years ± 7.1 years.
Procedure
A between groups repeated measures design approved by the University Ethics Committee was used to assess the impact of an 8-week myofascial release intervention designed to correct forward head posture on golf swing kinematics. The common experimental procedure was used to collect data using the Golf Biodynamics software as described in Chapter 3.
Training Intervention.
Each participant within the Experimental group was supplied with two spiky balls and was asked to undertake two self-administered myofascial release sessions daily, for eight weeks. Participants within were given instruction to correctly perform the five exercises and one training session a week was supervised by a researcher, primarily to check exercise form and technique. Remaining sessions were unsupervised, but each individual was asked to complete a training log book to record both supervised and unsupervised training sessions. Each session lasted approximately ten minutes in duration and involved five separate exercises some of which were performed in a bilateral manner. Myofascial release exercises involved the use of one or two spikey balls (McMaster Golf Systems, Australia) and are detailed in table 5.1. Exercises were completed in the order listed in table 5.1. Full pictures are shown and descriptions listed of each exercise used within the experiment group in Appendix B. Using the previous research by MacDonald et al. (2013) and Quinn et al. (2016), participants completed each exercise for 60 seconds as this was the recommended time for myofascial release. Also, the rationale was taken to have each participant complete each exercise twice a day, once in the morning and once in the evening due to the length of time spent in their habitual postures therefore this was considered a reasonable volume. Individuals in both the control and experimental groups were asked to continue their normal levels of golf play and practice and were asked not to undertake any conscious technique changes. They were also instructed not to embark in any new forms of exercise, aside from the intervention, but could continue with their normal routines. The participants were also provided with videos of the exercises with full narration as to how to perform the exercises correctly and a list of precautionary actions in the highly unlikely event of sharp pain or dizziness. This was listed on the guidelines for use of spiky balls as a disclaimer from the manufacturer and applied to all chapters in this study that incorporated the use of spiky balls.
Data Analysis and Statistics
Individual participant pre-test, post-test difference scores for each variable measured were calculated and any effects of the intervention on these variables were examined. This was carried out by within-subject modelling using an independent samples t-test on the change scores between pre and post-testing with group as the between samples factor (Control, Experimental). This provides a robust approach to the analysis and accounts for violations of asphericity (Hopkins, 2000). The overall type I error rate for each analysis was set at α=0.05. All data are reported as mean ± standard deviation and with 95% confidence intervals unless otherwise stated.
Results
The mean training session completion percentage for the Experimental group was 75±13% (CI 68-81%) with 78 of a potential 112 sessions completed on average (range 52-112). Head. The training intervention produced a greater change in the Headbend with the flexion in the anteroposterior plane reducing in the Experimental group post-intervention (t33=2.3, p=.03 r=.37, Table 5.1). There was also a difference in change in head-thorax alignment at address between groups (t29=2.5, p=.02 r=.42). There was no change in HeadrotA (t33=.8, p=.45 r=.14) but different changes in HeadrotT (t33=2.8, p<.001 r=.44) and HeadrotI (t33=2.1, p=.04 r=.34). These changes were evident in the head being less rotated to the right at the top of the backswing after training in the Experimental group whilst the Control group remained the same. At impact head rotation in the Control group was similar in its rotation to the left in pre and post trials, in the Experimental the head was on average more rotated to the left at impact in the post-trail having been slightly rotated to the right in pre intervention (Table 5.1). No differences were seen between the group’s pre-post change in head lift at the top of the backswing (t33=.45, p=.65 r=.08) in contrast there was a significant difference in the change in head lift at impact (t33=2.4, p=.02 r=.39). This was seen in a reduction in the drop of the head that occurred at impact in the control group whilst the Experimental group produced the same values pre and post intervention. There were no differences between groups in the changes in head sway between pre and post (HeadswayT, t33=1.0, p=.33 r=.17; HeadswayI, t33=.7, p=.94 r=.12; Table 2). For all head variables where a difference in change scores was seen between groups there was considerable heterogeneity in the individual change responses for each group, this can be seen in the standard deviations of the change scores in table 2.
Other variables.
There were no notable differences between groups in the pre-post change scores for any pelvic variables except for PelvicliftI (t33=2.3, p=.03 r=.37). This was reflected in a reduction in PelvicliftI for the Control group and no mean change in the Experimental group (Change scores: Control, 1±5cm; Experimental, 0±5cm). These changes resulted in an increase in the mean pelvic lift at impact in the Control group (2±2cm pre vs. 3±3cm post) and no change in the Experimental group (1±2cm vs. 0±2cm). There were no clear differences between groups in the pre-post change scores for any upper torso variable or segmental speeds.
Discussion
To my knowledge this is the first study that has looked at the impact of myofascial release to correct forward head posture in the golf swing. The eight-week intervention produced a change in head bend at address in the experimental group with a mean reduction in forward head bend of 4° from 64° to 60°, whilst the control group values remained constant. This change is similar in magnitude to that seen by Lynch et al. (2010) in standing posture although the angular measurement used differs. What is perhaps more important from a functional perspective in rotational movement is the relative alignment of the head and torso in the sagittal plane (Takeshima et al., 2002, Walmsley et al., 1996). The greater change seen in the torso- head alignment at address in the Experimental group resulted in a closer match of head and torso alignment (24±9° pre vs 18±12° post). This improved postural alignment may have resulted in the other kinematic changes seen in the experimental group during the swing with a reduction compared to the control group in the head rotation to the trail side at both the top of the backswing and impact. This would suggest that the myofascial release ‘freed up’ the head’s rotational movement allowing the participant to better maintain their head position and eye contact with the ball throughout the swing (Draovitch and Simpson, 2007). It would perhaps be expected that alteration in the kinematics of the head would have the potential to also impact upon those of the torso but in this study no such changes were seen. This may have been a result of considerable individual variability seen in the response to the intervention.
It is evident from the changes that have occurred that the intervention has impacted upon the kinematics of the swing at the group level but individually not all participants showed the same response. In interpreting the results presented here it is important to note the large degree of variability in the changes measured in the intervention group. In the intervention group some participants responded to the training with a reduction in head bend at address whilst other values remained relatively similar or even slightly increase (Figure 5.1).
This variability in response can be attempted to be interpreted from a dynamics perspective. Movement has been suggested to emerge from a dynamical system in which movement is coordinated in patterns which are influenced by task, organism and environmental constraints on the system (Newell, 1986). The intervention in this study has influenced the organism (golfer) in releasing and activating musculature around the cervical spine region resulting in a change in the forward head bend at address for those in the Experimental group. However, given the variability in the changes observed in a number of variables, it may be that these individuals are still learning how to optimize the new different possibilities for muscular synergies (Latash, 2010), that the intervention provides for them, within the coordinative system that is their golf swing with Langdown (2015) showing that changes in ball position can lead to variable movement within the golf swing therefore making associations between interventions often hard to predict due to the individual response golfers make. The participants in this study were all skilled golfers with low handicaps and it is probable that their underlying coordinative patterns for the swing were well established as seen in expert movement patterns in sport (Seifert et al., 2013) and until the internal representation of the movement and task have been adjusted then invariably motor patterns remain the same (Seegelke and Schack, 2016). With the intervention taking place in the low season for golf, and participants being asked to not to attempt any conscious swing changes, it is possible that some of the participants may not have understood what an appropriate head posture at address was for them. Their well- established coordinative pattern may have prevented some participants from making use of the changes resulting from the myofascial release, and this may have manifested itself in the considerable variability in response. To examine this future work should look at the effect of instruction alongside a training intervention, which would allow manipulation of interacting constraints to challenge the movement system to produce an adapted movement response (Seifert et al., 2013).
Conclusion
Eight weeks of a myofascial release intervention and head/neck postural re-education can improve the forward head posture of golfers standing in the address position and alter the kinematics of the head throughout the swing. These changes are individual and with considerable variability between participants. Consideration should be given to the potential additional role of instruction in affecting change in swing kinematics once the physical constraints on an individual’s address posture have been altered. It is likely that each individual will respond in a non-linear manner to this change as constraints are altered at differing rates through both physical intervention and instruction.