Current rehabilitation approaches for muscle weaknees at FAI. Are strength and conditioning programs effective in reducing strength deficits in FAI.

snowshrm · 14 Ιουνίου 2009

Abstract:

SC interventions that effectively reduce strength deficits in FAI, is not discussed in detail in the literature. The objective of this review was to indentify an evidence based SC intervention appropriate for clinical practice that reduces strength deficits in FAI.

Electronic and cross referencing pooled 33 articles of which four met the search criteria. Review showed a number of issues around the inclusion and exclusion criteria selected. However a number of issues in the design of those studies was also indentified. Strength training intervention of all studies did not have a sound foundation, possibly as a result of the broad direction of each study’s design. However two studies showed that inappropriate loading would not produce wished results, hence individual RM should be considered during rehabilitation. Nevertheless rehabilitation or injury prevention strategies that use SC prescription, must consider in full the sports sensorimotor and muscular physiological demands. Therefore strength and conditioning fundamentals should be revised in sports rehabilitation.

Although this review was unable to successfully answer the research questions, it was able to identify issues relevant to FAI and indentify research question that may further assist FAI research. Future designs that would consider this papers suggestions, may provide evidence based SC guidelines that effectively reduce the quantitative and qualitative strength deficits in FAI.

1. Introduction:

Currently available literature does not clearly identify the most effective strength and conditioning (SC) rehabilitation prescription for improving strength deficits for functional ankle instability (FAI). Therefore a literature review to evaluate SC rehabilitation programmes efficacy in reducing strength deficit evident in FAI is the focus of this review.

Ankle injuries occur to one in 10,000 people per day (Hertel^b 2002; Lynch 2002) while in the UK is suggested that 5,000 ankle injuries occur daily (Olmsted et al 2004). Eighty five percent of all ankle injuries concern the lateral ankle complex (Docherty^a, Moore, Arnold 1998; Sekir et al 2007). McKay et al (2001) reported that basketball players with a previous ankle injury were five times more likely to suffer a repeated ankle injury. This agrees with others that suggested that 70 to 80% of the athletes that with a previous lateral ankle ligament injury reported injury reoccurrence (Hertel^b 2002; Powers et al 2004). Repetitive lateral ankle injury has been characterised as chronic ankle instability (CAI). CAI is a broad term to describe dysfunction either to the mechanical or to the functional stability. However, both mechanical and functional insufficiencies may be present in individuals (Hertel^b 2002).

Mechanical ankle instability (MAI) is defined as ankle movement beyond the physiologic limit of the ankle’s range of motion (Tropp 2002). However, it is a broad term to include pathological laxity, altered arthrokinematics, degenerative and synovial changes (Hertel^b 2002). Freeman (1965) was the first to use the term functional ankle instability at the ankle to describe the subjective feeling of giving away (Docherty^b et al 2006; Kaminski^a et al 2003). Ever since, research on FAI has identified the feeling of giving away to be product of affected postural control, proprioception, strength and altered neuromuscular function (Caulfield 2000; Hertel^a 2000; Hertel^b 2002). In the literature the definition varies among researchers, for that reason this review used a definition accepted from other researches. FAI is the occurrence of recurrent ankle instability and the sensation of joint instability due to the contributions of proprioceptive and neuromuscular insufficiencies (Hertel^a 2000).

Strength deficiency as residual disability had been reported before Freeman’s work, suggesting that peroneals muscles weakness will allow a rotational translation away from the midline, overstressing the ligaments that result in frequent sprains (Kaminski^b, Hartsell 2002). Ever since, Kaminski^c et al (1999) and Willems et al (2002) supported the theory of peroneal muscle weakness were others refuting it and presented invertor (Munn et al 2003) or plantarflexors (Fox et al 2008) muscles with impairments. Muscle weakness, proximal the ankle, at the gluteus group, after LAS or subjects with FAI has also been reported (Bullock-Saxton 1994; Friel et al 2006).

A general review by Mattacola and Dwyer (2002) for rehabilitation of acute LAS and CAI provided a wide range of strengthening exercises and loading recommendations. However the authors (Mattacola, Dwyer 2002) did not include training variation or periodization, that is suggested to have great effects on sports specific, recreational and rehabilitative training goals (Kreamer, Ratamess 2004). Rehabilitation strengthening exercises for FAI or acute ankle sprain are initially prescribed with isometric and progress to isotonic exercises (Kaminski^b, Hartsell 2002; Mattacola, Dwyer 2002). Strength is defined, as the integrated result of several force producing muscles, to perform isometrically or dynamically for a given task (Hoff, Helgeruad 2004). This is measured by manual muscle testing, using handheld and isokinetic dynamometers (Kaminski^b, Hartsell 2002).

Inadequate rehabilitation that hastens return to play, earlier than the ligamentous ability to heal, is indentified as risk factor for injury reoccurrence. In football, poor muscular endurance has been identified to cause electromechanical delay to cause injury or injury reoccurrence (Woods et al 2003). Hence, non specific SC rehabilitation training and injury prevention prescriptions, which do not mimic the sports functional movements or sports muscular physiological demands, may also predispose to injury reoccurrence.

Repetitive ankle injury develops articular degeneration and osteoarthritis, thus the health care professional must effectively prevent further reoccurrence in FAI (Hertel 2002). Great concern is, when mechanical stable ankles present with FAI symptoms and eventually lead to mechanical ankle deficits (Hertel^a 2000; Hertel^b 2002). The graduate sport rehabilitator must adopt evidence based effective strength and conditioning rehabilitation and injury prevention approaches as to prevent or reduce strength deficit in FAI. Acknowledgment of successful strength training intervention may provide better information and improve current FAI rehabilitation and injury prevention strategies.

2. Methods:

A literature review was carried out to identify suitable studies, using cross referencing, the university’s online search engine (Athens) and public search engines (pubmed, google and scholar). The keys words used for the search engines included: functional ankle instability, ankle injury, ankle rehabilitation and ankle strength training.

This research required recent studies therefore search engines were limited to indentify articles published from 1998 till 2008. In order to qualify for this review study designs had to include a control group hence case reports were excluded.

Studies included had used strength training intervention for subjects with FAI and presented the strength training prescription as part of their work. Studies were excluded if they did not clearly describe the resistance devices they used. Investigations which failed to present inclusion and exclusion criteria for the candidates’ selection were not included.

3. Results:

3.1. Studies:

Thirty two articles were indentified from the electronic search engines and one through cross reference. Only four studies met the criteria of the current review. Docherty^a, Moore, Arnold (1998) investigated the effects of strength training on strength development and improvements in joint position sense. Kamiski^a et al (2003) investigated the effects of three different rehabilitation protocols after six weeks of training on eversion to inversion isokinetic strength ratios at subjects with unilateral functional ankle instability. Powers et al (2004) explored the effects of strength and proprioception exercises in increasing muscular fatigue. Sekir et al (2007) examined the effects of isokinetic exercise on strength, joint position sense and functionality.

3.2. Studies inclusion and exclusion criteria:

Docherty^a, Moore and Arnold (1998) study inclusion criteria defined FAI as the person with a history of at least three ankle sprains in the last five years. However, that study recruited candidates that had been diagnosed with a moderated ankle sprain and had sustained one episode of giving away in the last year. Further the Docherty^a, Moore and Arnold (1998) study included candidates that were physically active, similar to the inclusion criteria Kaminski^a et al (2003) and Powers et al (2004) used for their studies. On the contrary the Sekir et al (2007) study selected subjects where the volume of physical activity did not exceeded three times a week and more than half an hour per session.

Kaminski^a et al 2003 and Powers et al 2004 studies used identical criteria to carry out their investigations. Those studies used a questionnaire that required volunteers to answer yes to five specific questions and no to three specific questions to select candidates. In contrast Sekir et al (2007) selected subjects that reported at least two moderate sprains at the same ankle.

Of the four studies, three excluded candidates that were mechanically unstable (Kaminski^a et al 2003; Powers et al 2004; Sekir et al 2007). All the studies required their subjects not to participate at any formal rehabilitation sessions at the time of the studies (Docherty^a et al 1998; Kaminski^a et al 2003; Powers et al 2004; Sekir et al 2007).

Two studies included subjects, that had not suffered an injury to the affected ankle three months prior their investigation (Kaminski^a et al 2003; Powers et al 2004). In contrast Sekir et al (2007) included subject’s that uninjured side had not suffered an injury in the past six months. However these studies required their participants to be free from pain and swelling (Kaminski^a et al 2003; Powers et al 2004; Sekir et al 2007).

Two of the studies excluded candidates that had experienced an ankle fracture (Kaminski^a et al 2003; Powers et al 2004). Conversely Docherty^a et al (1998) and Sekir et al (2007) ensured that none of their candidates was subject to neuromuscular problems.

3.3. Subjects results and Group allocation

Ten female and 10 male healthy college students met Docherty^a, Moore and Arnold (1998) inclusion criteria. Average age 20.6(± 2.23) height was 176.4 (± 7.14) cm and weight 74.18 (± 10.17) kilograms. Kaminski^a et al (2003) and Powers et al (2004) recruited in total 38 subjects of which 22 were men. All subjects were college students of mean age 21.6 (± 2.9) years, height 174.1 (± 9.8) cm, weight 78.2 (± 16.6) kg.. However Sekir et al (2007) investigation identified 24 recreational male athletes as subjects, of mean age 21 (± 2).

Of the four studies, one used as control the contralateral healthy ankle (Sekir et al 2007). Kaminski^a et al (2003) and Powers et al (2004) randomly assigned their subjects to strength training only, proprioception training only, strength and proprioception and control groups. Docherty^a Moore and Arnold (1998) ensured that equal number of males and females were randomly assigned to either strength training or control group.

3.4. Strength training intervention:

Docherty^a and colleagues (1998) study strength training protocol was based on authors’ clinical experience that applied a progressive resistance regime for dorsiflexion, plantarflexion, inversion and eversion with the aid of Theraband (Theraband tubing resistive exerciser, The Hygenic corporation, Akron, OH).

Subjects of all studies had to participate for three sessions the week for total of six weeks period. Candidates performed the first week three sets of ten repetitions for all exercises with the blue band and applied same loading at the third and fifth week were black and silver colour band were used respectively. Week two subjects continue using the blue band progression included an additional set of ten repetitions. Similar loading progression was used at the fourth and sixth week where black and silver colour bands were used respectively. Kaminski^a et al (2003) and Powers et al (2004) carried out similar protocol and also the used same elastic band manufacturer. Though at those studies red, green and blue colour bands were used for progression. The elastic tubes were secured having the one end attached to a table or wall and the other end attached to the leg. Bands resistance was determined to be at 70% of the bands maximal stretch. Kaminski^a et al (2003) and Powers et al (2004) used the same method to calculate the resistance of the foiled band to be at 70% of the bands maximal stretch. All exercises were performed with the subjects seated on the floor with the knee fully extended and instructed to use only the ankle joint and were not allowed to produce any movement of the leg during the exercises.

Control group for those three studies (Docherty^a Moore and Arnold 1998; Kaminski^a et al 2003; Powers et al 2004) were instructed to continue participating in their physical activity without changing their training regime and avoid doing any strength training or applying other treatments to their ankles during the six week of the investigation.

The Sekir et al (2007) study strength training protocol used the Cybex Norm^TMto carry out the exercises. Subjects performed only at concentric mode for inversion and eversion at 120 degrees per second (120^o/s). At each movement was performed three sets of 15 repetitions per set for each session similar with the rest three studies.

3.5. Strength testing methods and materials:

Two studies measured strength with the use of isokinetic dynamometers (Kaminski^a et al 2003; Sekir et al 2007), another used a handheld dynamometer (Docherty^a, Moore, Arnold 1998) and one an electromyograph (EMG) (Powers et al 2004). Docherty^a Moore and Arnold (1998) measured all subjects for isometric strength pre and post the investigation with the aid of a hand-held dynamometer (MicroFET2, MicroFET, Draper,UT). The unstable ankle was tested for dorsiflexion and evertor strength while barefoot. Subjects had to perform three trials of isometric contraction each lasting for three seconds with ten seconds rest in between. The highest of the 3 isometric values was recorded as the subject's peak force.

The Powers et al (2004) study carried out a single trial before and after the six weeks of training and measured muscle fatigue with the aid of an EMG (Myopac, Run Technologies, Laguna Hills, Calif). EMG device specifications for raw data were set with collection at frequency bandwidth of 10–1000 Hz, CMRR 110 dB, input resistance of 1 MW, and sampling rate at 2000 Hz and further filtered from analogue-to-digital conversion. Data collection was made while the subjects perform a single leg balance maintained for one minute. Authors (Powers et al 2007) collected data for every five seconds during the sixty second period of the single leg balance. The initial five seconds were used as a baseline and compared with a total of 11 five second intervals.

Kaminski^a et al (2003) used a Kin Com 125 dynamometer, while Sekir et al (2007) used a Cybex Norm^TM dynamometer for his investigation. Kaminski^a et al (2003) subjects for the testing proposes were tested in a seated position with the chest and waist secured with straps. Testing was accomplished with footwear on and the ankle. The leg being tested was secured to eliminate unwanted muscle contribution. Kaminski^a and colleagues (2003) calibrated the dynamometer to stop at 15 degrees (15^o) of eversion and 25^oof inversion allowing a total 40^orange of motion to be performed from eversion to inversion and vice versa. Kaminski^a et al (2003) participants were tested in 30 degrees per second (30°/s) and 120°/s and for each velocity and motion three maximal trials were performed with 15 seconds rest between trials. One minute of rest was allowed when new velocity, motion and side was tested. Attempts in which subjects were unable to produce torque curve that did not matched previous attempts were repeated. Kaminski^a et al (2003) in an effort to minimize any learning effects randomized velocity and starting position of the foot by flipping a coin.

The Sekir et al (2007) study positioned subjects prone with seatbelt placed around the abdomen and secured the torso. The distal aspect of the thigh of the testing leg was strap secured and knee joint was placed at 80-110^o of flexion. In addition for that study Sekir et al (2007) placed the subtalar joint in neutral position and talocrural joint was positioned in 10–15⁰ plantarflexion. Subjects having their footwear on were strapped and secured on the isokinetic footplate. Sekir et al (2007) for the purpose of that investigation dynamometer was calibrated before testing for each subject to stop at 20^o of eversion and 30^o of inversion, and vice versa from inversion to eversion direction. Candidates of Sekir et al (2007) study were tested at velocity 120^o/s for eccentric and concentric actions of invertors and evertors muscles. Prior to testing a ten minute warm up of range of motion and stretching exercises for the ankle was carried out. Three submaximal repetitions familiarise subjects with the testing procedure prior to data collection followed by five maximal concentric and eccentric contractions for the invertor and evertor trials. Authors in that study allowed two minutes rest between the inversion and eversion tests to avoid fatigue.

3.6. Data

Three of the studies had set priori level of significance at p < 0.05 for all analyses (Kaminski^a et al 2003; Powers et al 2004; Sekir et al 2007). Docherty^a et al (1998) study it is unclear whether authors had set p < 0.05 post hoc. Three of the studies used SPSS to analyse their data (Kaminski^a et al 2003; Powers et al 2004; Sekir et al 2007), whereas in one study (Docherty^a et al 1998) is unclear if data was analysed by hand or with the use of software. Docherty^a et al (1998) used repeated-measures multivariate analysis of variance (MANOVA) to analyse the six dependent variables. Within subjects factor was pre and post testing and between subject factors was group membership. MANOVA tests were further followed by univariate analysis of variance (ANOVA). Authors (Docherty et al 1998) to locate specific group differences carried out post hoc significant univariate F tests.

Kaminski^a et al (2003) used mixed model ANOVA with repeated measures on the test factor. Within subjects factor was testing and between subject factors was group membership. Separate analyses were conducted on each of the four dependent variables. Independent variables of that study were test and group status.

To determine differences for fmed pretest and posttest, Powers et al (2004) used mixed-design ANOVA. Between subjects factor was group status the within subject factors were test and time. Differences of interest were examined post hoc with Tukey’s honestly significant difference analyses.

Sekir et al (2007) used two tailed tests and further examined using paired t-tests within the groups for differences pre and post the six weeks while for the differences between groups used unpaired t-tests. Data for within group differences between were skewed using Wilcoxon’s signed rank tests. Data for between group differences Mann–Whitney U-test was used. Ankle evertor and invertor muscle strength percentage changes in isokinetic testing the Pearson product-moment correlation test was performed.

snowshrm · 14 Ιουνίου 2009

4. Discussion:

4.1. Inclusion exclusion criteria

Docherty^a, Moore and Arnold (1998) study despite that had defined FAI for the inclusion criteria, authors used minimum criteria to qualify candidates as functionally unstable, thus allows questions around consistency of the study. Sekir and associates (2007) selected subjects that reported at least two moderate sprains at the same ankle. Two studies were not interested their subjects to report the amount of sprains they had suffer and questionnaire may benefit if minimum amount of sprain was included (Kaminski^a et al 2003; Powers et al 2004).

Docherty^a, Moore and Arnold (1998) required subjects to be asymptomatic for the study, however this is a broad term. In contrast three studies included candidates that were free from pain, swelling and ecchymosis at the time of the investigations (Kaminski^a et al 2003; Powers et al 2004; Sekir et al 2007). The Sekir et al (2007) study excluded any subject that uninjured side had suffered an injury six months prior their study. However, Kaminski^a et al (2003) and Powers et al (2004) studies did not include subjects that had suffered from injury on the affected ankle three months prior the investigation. Likewise differences are observed in other studies investigating FAI.

A study (Buchanan et al 2008) that observed the functional performance in two hopping tests at subjects with FAI, defined physical activity as “participating in exercise at least twice each week”. Brown and Mynark (2007) defined physical activity as “participating in at least 20 minutes of physical activity three times per week”. Physical activity level was defined only by one study (Sekir et al 2007) presented in this review. Nevertheless this shows that there is no common agreement in defining physical activity of the sample.

Munn et al (2003) investigation narrowed their candidate selection excluding any individual that may have any “neurological dysfunction affecting muscle strength or postural control”. However such exclusion was observed only in two of the selected studies (Docherty^a et al 1998; Sekir et al 2007).

Kaminski^a et al (2003) and Powers et al (2004) used a questionnaire as inclusion, which also has the ability to indentify the individual with FAI. However authors of those studies could have integrated Rozzi’s et al (1999) questionnaire that also assess the ankle joint performance at functional tasks and observe qualitative changes as result of an intervention. Nevertheless none of the studies (Docherty^a et al 1998; Kaminski^a et al 2003; Powers et al 2004; Sekir et al 2007) incorporated assessment of the qualitative effects for their interventions.

Ever since Freeman explained FAI as the subjective feeling of giving away, this has remained the gold standard identifying FAI in individuals (Buchanan et al 2008; Docherty^b et al 2006; Kaminski^a et al 2003). Hence to apply qualitative methods to observe improvement of the subjective feeling of giving away, of an intervention may be as important as quantitative methods. Future investigations that will use an intervention to reduce FAI deficits may benefit even more if researches include qualitative assessment tools. send

Some of the differences presented come in agreement with Docherty^b et al (2006) that observed a variance of the inclusion-exclusion criteria used in research to define FAI. However, Korandsen (2000; 2002) had already presented that FAI has no universally accepted definition. Investigators should focus to construct a gold standard of exclusion and inclusion criteria that define FAI, to investigate and compare FAI dysfunctions.

4.2. Subjects and group allocation:

Two studies had identical total number of candidates, even identical number of male and females. Further anthropometric characteristics were identical between those two studies. The similarities allow to speculate that those two studies were part of a larger experiment rather than individual designs (Kaminski^a et al 2003; Powers et al 2004).

Docherty^a et al (1998) managed to recruit equal number of males and females, however, the Sekir et al had only males. The Kaminski^aet al (2003) and Powers et al (2004) studies however had 22 males and 16 females. The Sekir et al (2007) study could have also included females, however, authors of that study appear that practice at military hospital hence the presence of females may had been prohibited. However that study in contrast with other three did not present in detail the anthropometric characteristic of their candidates.

Docherty^a et al (1998) and Sekir et al (2007) presented in detail the group allocation. The Docherty^a et al (1998) allocated equal number of females and males at control and intervention group. The Powers et al (2004) and Kaminski^a et al (2003) studies could have also allocated equal number of males and females, however those studies carried out three interventions and allocated the subjects randomly.

4.3. Testing methods and material:

Isokinetic dynamometers offer the ability for isometric strength testing that eliminates examiners biased data collection (Kimura et al 1996). The Docherty^a, Moore and Arnold (1998) study could have benefit even more, if authors had considered using a isokinetic dynamometer. However two studies (Kaminski^a et al 2003; Sekir et al 2007) that used isokinetic dynamometers could have included in their testing isometric testing. That additional testing would have offered a better discussion of either argument or support for Docherty^a, Moore and Arnold (1998) study.

Two studies used isokinetic dynamometers, although one used a Kin Com 125 dynamometer (Kaminski^a et al 2003) and the other used a Cybex Norm^TM(Sekir et al 2007). However as far as concern this review was unable to find a different study addressing the reliability of Cybex Norm^TM.

Sekir et al (2007) allowed his subjects two minutes of recovery between tests minimizing systematic bias cause that could be caused from fatigue (Atkison^a, Nevill 1998). Kaminski^a et al (2003) allowed a minute rest between tests though Docherty^a et al (1998) that allowed 10 seconds rest between testing trials and observed an increase in strength post the six weeks of the strength training. Nevertheless results of that study due the short resting time between testing may had been affected from post-activation potentiation effect that is proposed to be evident during isometrics (Babault, et al 2008; Batista et al 2007).

Sekir et al (2007) detailed described subject positioning on the dynamometer in contrast with Kaminski^a et al (2003) that did not. Additional difference between the studies is that one tested at two different velocities where as the other tested at one. Comparison would have been even better if Sekir et al (2007) had considered including testing at 30 degrees per second. However if Sekir et al (2007) had considered to investigate for average torque data would had allowed a better comparison between the studies.

Powers et al (2004) used an EMG to observe the median frequency of PL and TA thus comparison between the current studies is impossible. Although study design may have been strengthen if author (Powers et al 2004) had considered using an isokinetic dynamometer as Gutierrez et al (2007) study used along with an EMG device to observe fatigue. Nevertheless for that study subjects were trained at dynamic movements and not at isometrics that are been advocated as advance SC training (Kreamer, Ratamess 2004). In a similar manner Powers et al (2004) may have different results if subjects had been tested at dynamic movement using weight machine or bands. However, even if the appropriated assessment tools and appropriate SC prescription was indentified and used, it is questioned if a sample from random sport background would had benefit from such intervention or testing. Bressel and associates (2007) tested females from three different sports on a balance drills they found that gymnasts had better balance from basketball players and suggested that dissimilarities were due to different sensorimotor challenges of each sport. Perhaps selecting individuals from a specific sport and select methods specific to the sports sensorimotor and muscular physiological demands, may provide different information that may allow a better understanding about FAI.

Initially strength development is as a result of neural or metabolic responses (Behm 1995; Kraemer, Ratamess 2004). Three studies (Docherty^a et al 1998; Sekir et al 2007; Kaminski et al 2003) could had benefit even more if authors had used an EMG device during pre and post strength measurements and observed for changes in neural drive (Behm 1995; Gabriel, Kamen, Frost 2006; Kraemer, Ratamess 2004). However none of the studies considered the relationship of neural adaptation, rate of coding and strength development.

Inappropriate choice of testing to observe an effect of an intervention may provide elusive results. Atkison^b and Nevill (2001) suggested that a careful planned research design that can be enhanced through literature review is more important that the statistical analysis, nevertheless a researcher should carefully plan his/her research.

4.4. Training protocol materials and methods:

Three studies carried out similar training protocols, one attempted a different protocol. Kaminski^a et al (2003) modified Docherty^a et al (1998) strength training protocol, however Powers et al (2004) used for his study Kaminski et al (2003) modified strength protocol.

Loading at those three studies was accomplished with therabands. Despite that authors of those three studies (Docherty^a 1998; Kaminski^a 2003; Powers 2004) described the elongation method they failed to specify the band’s length. Thus investigators prevent in that way, future researchers to replicate their studies. Furthermore of two studies had their bands folded, however Docherty^a et al (1998) study is unclear if they had the band foiled. Additionally Docherty^a et al (1998) used higher resistance bands in contrast with two studies (Kaminski^a et al 2003; Powers et al 2004) that used lighter resistance bands. Strength development loading has been suggested to correspond for novice at 60-70% and for intermediated 70-80% of the one repetition maximum (1RM) (Kraemer, Ratamess 2004). However estimation of the load that applied is unclear, since length of the bands that was used was not included.

Sekir et al (2007) applied 15 repetitions per set for his strength protocol, however high repetitions are associated with the endurance element of SC. Fundamentals of strength and power development suggested a low or medium repetition prescription (Kraemer, Ratamess 2004). Authors (Sekir et al 2007 to improve strength of the participants used an isokinetic device, however authors did not take in consideration that such devices main effect is the movement at specific speed, hence the force been produced may be maximal or submaximal (Knight, Ingersoll, Bartholomew 2001). Sekir et al tested for peak torque and perhaps the study could had benefited if authors had considered using a more suitable strength protocol. However even if a better protocol was considered development of maximal strength requires 70-80% of the 1RM loading (Kraemer, Ratamess 2004). Nevertheless none of the studies considered using a pulley exercise machine to strengthen candidate’s ankle complex.

Powers et al (2004), was interested in changes at fatigue after six weeks the intervention, for that study authors replicated a strength protocol published in the literature. Conversely if authors (Powers et al 2004) had considered the SC guidelines for endurance training, they may have observed a improvement in fatigue. However Powers et al (2004) and Kaminski^a et al (2003) findings support that inappropriate loading, will not have significant effect in reducing strength deficits in FAI or developing strength in healthy individuals.

Is important for the SR to prescribe a SC that will reduced ankle strength deficits based on the sports sensorimotor and muscular physiological demands. The individual that competes in sprinting will benefit mostly from strength/power training rather endurance which will benefit a long distance runner. Nevertheless when developing a research question one should consider if the intervention would be appropriate to observe an effect in a specific sample.

4.5. Studies conclusions :

Sekir and associates (2007) concluded that training the functional unstable ankle with isokinetic dynamometers is an effective approach in reducing strength deficits and improve proprioception in FAI. However study could have suggested recommendation for future designs.

Docherty^a et al (1998) closed the paper convinced of the success of their strength training. Major focus of discussion in that study was the improved muscle spindle sensitivity.

Kaminski^a and associates (2003) despite the unsuccessful outcomes of their intervention, presented some useful conclusions. Authors (Kaminski^a et al 2003) proposed to examine the intensity of training and offer guidelines on how strenuous the training exercises must be to bring about changes in strength”. The paper closed with the suggestion that strength testing protocol should be develop to closely match the strength intervention.

Powers et al (2004) and associates close their paper recognizing that their strength protocol may have been an inappropriate training stimulus for their subjects. However authors promote future investigation to replicate their design for acute stage of rehabilitation and examine the results of a more strenuous rehabilitation training protocol to subjects clear of the acute phase.

5.Conclusion:

All four presented studies showed great differences in their methods and materials to observe the effects of strength training in reducing strength deficit at the functional unstable ankle. Those differences and flaws lead this review to the conclusion that there is not a evidence based SC rehabilitation intervention effective in reducing strength deficits in FAI. However the weakest point of all the studies was the inappropriate prescription of their strength training.

Nevertheless, it was found that unsuitable loading would not offer significant difference. The inability to answer the research question may had been because of studies broad designs. Another factor that perhaps affected papers research may had been the differences in terminology. The studies used strength training, however this paper was interested in evidence based SC rehabilitation prescriptions.

Those studies, however, offered an important foundation, to develop a better research design that may answer this research question. This paper recommends that the research question should be as following:

“ What are the long and short term quantitative and qualitative effects of a structured SC programme compared with a novel programme in reducing strength deficits in FAI.”

To successfully answer that question a researcher should initially focus on the selection of the inclusion and exclusion criteria. The recruitment of the sample as shown in the paper will affect the selection of the most suitable SC prescription, testing and apparatus for data collection. Hence this paper is unable to specifically suggest the best choices as one affects the other. Therefore is remind that power SC prescription will need an power related test and power related athletes. According the aspect of strength that is to be developed SC intervention should be developed under evidence based theory. Prior and post testing qualitative assessment apparatus should be researched and reviewed prior investigation. Data analysis selection for a new investigator must be reviewed by a experienced investigator (Atkison, Nevill 1998).

The review has lead the author when applying SC intervention to FAI or LAS one should consider hip muscle and core strengthening. The rationale of this observation was conceived by considering that hip abductor and adductors control, respectively, the medial and lateral sway of the centre of pressure (Griblle, Hertel 2004). Additional by definition that strength is the integrated result of several force producing muscles (Hoff, Helgerud 2004) produce a sound theory to prescribe such intervention safely in practice. However, the meaningfulness following such a concept must be supported by evidence based experimental designs.

Nevertheless, if presence gluteal weakness is accepted following LAS or in FAI this would affect the current approach and alters muscle weakness definition. Thus assessment for LAS or FAI, the clinician should include proximal to distal approach. Positive finding will enable the SR to rehabilitate proximal to distal of the kinetic chain during acute stage.

snowshrm · 14 Ιουνίου 2009

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