THE IMMEDIATE EFFECTS OF A TOTAL MOTION RELEASE® WARM-UP ON ACTIVE ROTATIONAL HIP RANGE OF MOTION IN OVERHEAD ATHLETES

Abstract

Background

Reductions in hip range of motion (ROM) correlate with lower extremity injury and alterations in shoulder mechanics in overhead athletes. Such shifts in kinetic-chain dynamics may lead to additional stresses at common injury sites of the upper and lower extremities. Researchers have suggested that Total Motion Release^® (TMR^®) increases shoulder ROM more effectively than traditional warm-up methods. It is plausible that similar methods may produce increases in ROM at the hip.

Purpose

To explore the effects of a TMR^® based intervention on active hip rotational ROM in overhead athletes compared to a traditional athletic warm-up.

Study Design

Randomized Control Trial.

Methods

Twenty-two secondary school, NCAA Division I, III, and Club student-athlete participants (sex: 13 females, 9 males; sport: 9 javelin, 7 volleyball, 7 baseball; age = 19.3 ± 1.1 years; height = 178 ± 11.4 cm; weight = 76.4 ± 11.2 kg.) were randomly assigned to TMR^® (TMRG; n = 11) and traditional warm-up (TWG; n = 11) groups. The TMRG performed three sets of forward flexed trunk twist and seated straight leg raise held for 20 seconds each to the side of ease with a 30-second rest interval. Active hip internal and external rotation was measured using the Clinometer smartphone application immediately before and after intervention.

Results

The TMRG experienced significant immediate increases in active dominant hip ER,, active nondominant hip ER, active dominant total hip rotational ROM, and active nondominant total hip rotational ROM (mean _change = +6.27°, + 12.2°, + 4.8, and +11.9°), compared to the TWG (mean _change = +0°, + 1.9°, -1°, and 1°) respectively.

Conclusion

Using TMR^® motions and principles as a warm-up produced meaningful changes in active hip rotational ROM bilaterally in overhead athletes.

Level of Evidence

IIb

INTRODUCTION

The importance of trunk stability prior to coordinated movement of the extremities has been well established in the literature,^1,2 as have the dynamic kinetic-chain links between the lower and upper extremities in overhead athletes.^2-6 The interdependent nature of the upper and lower extremities in overhead athletics is crucial when considering injury risk and athletic performance.^6-9 Due to kinetic-chain relationships in overhead athletics, the hip becomes a joint of primary interest when evaluating performance metrics and injury risk.^3,7-12 For example, previous researchers have suggested that decreases in kinetic energy at the hip and trunk may result in reduced shoulder stability and increased rotational velocity demands at the shoulder in order to produce distal force.¹³

Increased hip range of motion (ROM) may have positive effects on performance and injury prevention in a variety of overhead athlete populations.^7-9 For example, world class javelin throwers have been found to possess significantly greater hip axis rotation at release when compared to national class javelin throwers.⁹ Others have suggested that alterations in hip ROM may correlate with changes in shoulder external rotation (ER) ROM in baseball position players and pitchers with a history of injury at the shoulder.^7,8 Decreased hip extension has also been correlated with risk of shoulder injury while decreased total hip arc ROM has been found to predispose baseball players to lower extremity injury.^7,8 Reduced active and passive hip rotation ROM has also been suggested to correlate with low back pain in a variety of populations participating in athletics.¹⁴ However, there is a lack of literature examining injury risk and active hip rotational ROM changes in a variety of overhead athlete populations. Results from early research efforts in this area indicate that retired competitive javelin throwers exhibit reduced hip IR ROM, and suffer from hip arthrosis at a rate three times higher than age and body mass index (BMI) matched controls.¹²

Despite the gaps in the literature, increasing ROM is a common goal when preparing athletes for sport through the use of warm-up activities. Historically, static stretching and dynamic warm-ups have been the primary components of interventions used to increase hip and shoulder ROM in athletes.^15,16 While warm-up activities are often designed based on previous experience, support exists in the literature for the sequencing of activities, such as aerobic exercise, static and dynamic stretching, and sports specific exercises.^15,16 Stretching activities to improve hip ROM have often been targeted at the piriformis muscle, with the ‘modified lunge’ and ‘figure 4’ stretches being common strategies.¹⁷ Bremner et al¹⁷ however, found no significant change in hip passive IR or ER ROM with the use of these stretches when compared to a control group. Despite the commonality of warm-up and stretching protocols, research is not definitive on whether these interventions achieve short or long term improvements in hip IR and ER.

Figure 4.

Measurement of Active Hip Internal Rotation.

Recently, researchers have suggested that rapid increases in ROM can be achieved through the use of a technique called Total Motion Release^® (TMR^®) citing gains in shoulder ROM in overhead athletes^18,19 and the alleviation of apparent hamstring tightness.²⁰ Theoretically, TMR^® acts largely on neuromuscular control via cross education,²¹ neural coupling,²² and the common core hypothesis,²³ as well as the interconnected nature of fascial and muscular tissues throughout the body known as biotensegrity.²⁴ Operating with the notion that pain may affect motor control,²⁵ clinicians using TMR^® seek to alleviate pain and dysfunction through the specific use of pain free movement to alter pain and dysfunction in other body regions.^18-20,25 When using TMR^®, patients are directed to perform movement patterns bilaterally, while comparing pain, quality of movement, and or ROM on a scale of 0-100.²⁵ On this scale, 0 represents no pain, dysfunction, or strength deficit, with the patient/athlete perceiving normal quality and quantity of movement.²⁵ A score of 100 on the scale represents extreme pain, complete dysfunction, complete unilateral strength deficit, or severe loss of quality or quantity of motion.²⁵ If a given movement pattern is bilaterally painful treatment with TMR^® in that specific motion is contraindicated.²⁵ After these self-determined ratings are established, the patient is treated by performing the motion with the largest TMR^® score on the “good” side (i.e., healthy side) instead of the “bad” side (i.e., dysfunctional side) utilizing static holds at end range or set/rep schemes through the ROM.²⁵ The intervention is continued until the patient reports less than 5% asymmetry in the treated motion or has been addressed in excess of five rounds of treatment in a given session.²⁵

Given the previous findings of TMR^® ROM studies, and the relationships between hip ROM, injury, and performance deficit risk in overhead athletes,^7-9,12 further investigation into the effects of these TMR^® methods on active hip ROM in overhead athletes is important. The purpose of this study was to explore the effects of a TMR^® based intervention on active hip rotational ROM in overhead athletes compared to a traditional athletic warm-up.

METHODS

The University of Idaho Institutional Review Board granted approval prior to data collection. A randomized control trial design was used to investigate the effects of a TMR^® intervention (TMRG) and commonly used athletic warm-up strategies (TWG) on active hip rotational ROM. A convenience sample 22 student-athletes (n = 11 from National Collegiate Athletics Association [NCAA] Division I volleyball and track and field; n = 3 from NCAA Division I Club Baseball; n = 3 from NCAA Division III track and field; n = 5 from high school baseball and volleyball teams) were recruited to participate in the study. For inclusion, participants were required to be between the age of 18-25, be able to complete all warm-up activities and ROM measurements, and have been competitive in their respective sport for at least three consecutive years. Exclusion criteria included any orthopedic surgery to the hip, knee, ankle, spine, shoulder, or elbow in the previous three months. Those who suffered orthopedic injuries older than three months yet remained symptomatic were also excluded. Participants were also excluded if they were unable to complete hip ROM testing or had painful motion with both left and right straight leg raise or trunk rotation during pre-screening as this is a contraindication for the use of the included TMR^® motions.²⁵ All participants signed informed consent with the understanding that participation was voluntary and withdrawal from participation would be accepted at any time. Participants were also informed that their data could be withdrawn from use in this study after collection was complete. No participants were excluded after prescreening or discontinued participation after data collection had begun. Gender and sport differences between groups are displayed via a CONSORT flow chart (figure 1).

Figure 1.

CONSORT diagram showing the breakdown of participant by intervention, gender, and sport.

PROCEDURES

The Clinometer^® digital smartphone application by Plaincode Software Solutions (https://play.google.com/store/apps) was used to measure active hip IR and ER immediately before and after intervention.²⁶ The examiner affixed a smartphone to the participant's anterior shin with the top edge of the smartphone in line with the proximal terminus of the tibial tuberosity using an Ailkin Running Sports Armband for Droid Turbo^™ Android Smartphone by Motorola (app; figure 2). For IR and ER measurements, participants were seated with the hip and knee of the limb being measured at 90° with the lower leg draped over the edge of the plinth. An adjustable strap was positioned across each participant's thigh at the distal third of the femur to limit compensation during ROM testing. The unmeasured limb was positioned at a diagonal with the knee at 90° draped over the lateral edge of the plinth to ensure unimpeded rotational AROM to the measured limb (figure 3).

Figure 2.

The Smartphone Clinometer application affixed in the Ailkin Running Sports Armband for Droid Turbo^TM.

Figure 3.

The Adjustable Belt used for Leg Stabilization during Active Hip Internal and External Rotation measurements.

The examiner was seated across from the participant near the leg during active IR and ER to allow the examiner access smartphone for use of the Clinometer^® application. In order to determine dominance, participants were asked to select the arm they primarily use for competitive activity. Hip dominance was determined to be the limb ipsilateral to the dominant arm.^3,4 The leg was positioned with the gastrocnemius two inches away from the edge of the plinth. Once positioned, the participants were instructed to internally rotate then externally rotate the hip, making sure to minimize accessory motion by keeping the gluteal region level and in contact with the plinth and the knee flexed to 90°. Asking the participant to keep their hands in their lap, limiting their ability to stabilize against the plinth, minimized accessory stabilization. Measurements were recorded when the participants reached self-determined end range (figure 4; figure 5). The sum of hip IR and ER was used to determine total hip rotational ROM.

Figure 5.

Measurement of Active Hip External Rotation.

Prior to the completion of this study, intra-rater reliability pilot data was collected using the Clinometer^® application. The examiner measured hip IR and ER five times with the smartphone application, thigh strap, and sport band averaging the values. The examiner placed the smartphone and participants in the position for measurement. Measurements were conducted on each participant (n = 10) twice over a period of five days. A two-way mixed effects model Intraclass Correlation (ICC) was used to assess intra-rater reliability (test-retest) for the Clinometer^® smartphone application with absolute agreement. The standard error of the mean (SEM) values were calculated for hip IR and ER using the formula (SEM = SD√1- ICC) where SD is the standard deviation from the test.²⁷ Minimal Detectable Change (MDC) was calculated using the formula (MDC = SEM × 1.96 × √2).²⁶ The intrarater reliability ICC, SEM, and MDC values were excellent for both measurements and exceeded those previously reported in the literature for both active seated hip IR (ICC = .84, SEM = 3.4) and hip ER (ICC = .63, SEM = 2.8) (Table 1).^26,27

Table 1.

Intra-rater reliability for hip internal & external rotation using the Clinometer application (N = 10).

Active Range of Motion (AROM)	Intraclass Coefficient (ICC)	Standard Error Measurement Value (SEM)	Minimal Detectable Change Value (MDC)
Hip Internal Rotation	.903	1.18	3.27
Hip External Rotation	.947	0.65	1.8

Data collection and intervention were conducted in a single session for each participant prior to any sport-specific warm-up activities, training, or competition. Participants were assigned to either the TMR^® group (TMRG) or the traditional warm-up group (TWG) randomly based on the order of signup or arrival for participation. Pre-intervention measurements of active hip IR and ER were measured beginning on the dominant side and then moving to the non-dominant side prior to performing the activity assigned to either the TMRG or TWG.

After baseline AROM measurements were collected, the participants in the TMRG performed one SLR with each leg and FFTT with the arms folded across the chest and the palm of the hand at the anterior deltoid. During the FFTT, the participant's hips were slightly hinged as if performing a deadlift, with the torso at an angle that produced no discomfort in the participant's back. Hip angle, hinge depth, and trunk posture were not controlled for per the TMR^® systems suggestion that participants reach self-determined end range and that changes in joint angles and position during testing and intervention are required to do so.²⁵ All interventions and measurements were provided by an athletic training student and certified strength and conditioning coach (CSCS) who had been trained in TMR^® up to level III. Measurement and application of interventions took place indoors in athletic training facilities.

TOTAL MOTION RELEASE^® GROUP (TMRG INTERVENTION)

Participants in the TMRG then established a “side of ease”, per their own perception, for both the TMRG SLR (figure 6) and FFTT (figure 7) per TMR^® recommendations.²⁵ Afterward, participants performed these movement patterns in order from most asymmetrical to least asymmetrical. The FFTT and SLR were chosen because previous research on TMR^® has indicated that related movements could produce either regionally interdependent or local changes in ROM. For example, the TMR^® FFTT and arm raise (AR) significantly increased shoulder rotational range of motion in baseball players.^18,19 Furthermore the TMR^® FFTT was reported to significantly increased measures of hamstring extensibility, including the sit and reach and active straight leg raise tests.²⁰ The researchers sought to test the effect of the TMR^® FFTT and a comparable lower extremity TMR^® motion (i.e., the SLR is similar to the AR technique in TMR®) coupled with the FFTT on hip rotational AROM.

Figure 6.

The Total Motion Release® (TMR®) Seated Leg Raise (SLR).

Figure 7.

The Total Motion Release® (TMR®) Forward Flexed Trunk Twist (FFTT).

The seated SLR (3 sets of 20-second static holds at end range) and the standing FFTT (3 sets of 20-second static holds) were performed to the side of ease in the case of the SLR or the direction of ease during the FFTT. After each set, a 30-second rest interval was taken by the participants. End range holds of 20 seconds were performed in an attempt to reduce cumulative fatigue while completing multiple rounds of high-volume repetitions and sets.²⁸ Upon completion, hip IR and ER AROM were again recorded. The TMRG, including pre and post-participation AROM measurements, was completed in approximately seven minutes per participant.

TRADITIONAL WARM-UP GROUP (TWG INTERVENTION)

Participants in the TWG completed a four-part warm-up (Table 2), with Part I consisting of a three-minute steady state jog.¹⁶ Part II included dynamic full body warm-up drills consisting of upper and lower extremity dynamic stretches, dynamic movements through three planes of motion, and an emphasis on full range motion throughout the lower extremity, trunk, and upper extremity.¹⁶ The timing of Part II included three continuous rounds with a 30-second rest interval between each round. Part III included two rounds of 30 meter runs at 50%, 75%, and 90% of the participants’ self-determined maximum, and included a 30-second rest interval after each effort.¹⁶ Part IV included three rounds of 30-second static stretches for the upper extremity done alternatingly to produce a 30-second rest interval between sides.¹⁵

Table 2.

The Traditional Warm-up Protocol.

Warm-up Exercise	Repetitions
Phase I
Jog	3 minutes at 25% effort
Phase II
Walking Knee Hug	10 meters
Alternating Forward Lunge w/ Rotation	10 meters
Alternating Reverse Lunge w/ Rotation	10 meters
Alternating Walking Quadriceps Stretch	10 meters
Power Skips	10 meters
Alternating Lateral Lunges	10 meters
Walking dynamic forward overhead arm circles	10 meters
Walking dynamic reverse overhead arm circles	10 meters
Walking horizontal cross body arm swings	10 meters
Phase III
Sprint (50%)	2 × 30 meters
Sprint (75%)	2 × 30 meters
Sprint (90%)	2 × 30 meters
Phase IV
Alternating seated cross body stretch	3 × 30 seconds each
Alternating seated upper trapezius stretch	3 × 30 seconds each
Alternating side lying sleeper stretch	3 × 30 seconds each

Programs to address pre-training and pre-competition warm-up are often aimed at increasing heart rate, as well as core and specific tissue temperature.^15,16 Mobility and ROM are typically attended to through general exercise, static or dynamic stretching, and drills to address sport specific skills or performance aims.^15,16 However, static stretching of the hip was not included in the TWG due to a lack of definitive research regarding its effect on hip rotational ROM and its inconsistent use in overhead sports.¹⁷ Instead, dynamic training methods were utilized in Part II of the TWG because these movements were considered adequate for addressing the goals of a warm-up for overhead athletes who are preparing their lower extremity. Static stretching of the shoulder was included in part IV of the TWG because this is common practice among overhead athletes during pre-training and pre-competition preparation.^18-19 The TWG intervention was completed in approximately 25 minutes per participant. Upon completion of either intervention, hip AROM measurements were immediately reassessed.

STATISTICAL METHODS

Data analysis was completed using the Statistical Package SPSS Version 21 (IBM Corp. Armonk, NY, USA). Group baseline differences for hip IR, ER, and total hip rotation were analyzed using independent t-tests. One-way ANOVAs were used to assess the difference between groups regarding change in hip IR, ER, and total hip rotation post-intervention. An α level of p ≤ .05 was considered significant for all statistical analyses. Partial eta squared was utilized to calculate effect size, with values lower than .0099 considered small, while .0588 was the benchmark for medium, and values greater than .1379 considered large.²⁹

RESULTS

All 22 recruited participants met inclusion criteria and completed participation in this study (figure 1). Participants were randomly assigned to either the TMRG or the TWG using a numerical list generated by randomization.com in the order of participant arrival. Analysis of baseline testing indicated significant group differences in mean height (p = .003), but significant group differences were not found for age (p = .349) or weight (p = .188; Table 3). Additionally, no significant group differences were found in pre-intervention dominant hip IR (p = .388; Table 4), dominant hip ER (p = .362; Table 4) dominant total hip rotational ROM (p = .781; Table 4), nondominant hip IR (p = .851; Table 5), nondominant hip ER (p = .228 Table 5), or nondominant total hip rotational ROM (p = .421; Table 5).

Table 3.

Descriptive Statistics (Height, Weight, Age).

	Height (cm)	Age (years)	Weight (kg)
Participants	178 ± 11.43	19.3 ± 1.1	76.2 ± 10.9
TMRG	184.7 ± 10.41	19.5 ± 1.29	79.3 ± 10.78
TWG	171.6 ± 7.64	19 ± 0.89	73.1 ± 10.66

Table 4.

Dominant (DOM) Hip Active Range of Motion by Group.

Active ROM	DOM Hip Total ROM Pre	DOM HIP Total ROM Post	DOM Hip Internal Rotation (IR) Pre	DOM Hip IR Post	DOM Hip External Rotation (ER) Pre	DOM Hip ER Post
TMRG	77.5° ± 14.1°	89.6° ± 16.4°	32.6° ± 8.7°	39.8° ± 11.2°	43.6° ± 6.3°	49.1° ± 8.8°
TWG	83.4° ± 11.7°	85.3° ± 14.3°	36.5° ± 11.4°	38.2° ± 7.9°	46.9° ± 9.8°	47.1° ± 13.1°

Table 5.

Non Dominant (NON DOM) Active Hip ROM by Group.

Active Range of Motion (ROM)	NON DOM Hip Total Rotation Pre	NON DOM HIP Total Rotation Post	NON DOM Hip Internal Rotation Pre	NON DOM Hip IR Post	NON DOM Hip External Rotation (ER) Pre	NON DOM Hip ER Post
TMRG	77.5° ± 14.1°	90.4° ± 11.6°	34.5° ± 6.07°	39.9° ± 9°	45.2° ± 7.9°	51.2° ± 7°
TWG	85.2° ± 13.3°	86° ± 14.8°	35.1° ± 9.3°	36.6° ± 7.8°	50.1° ± 10.4°	49.4° ± 11.2°

Post intervention, significant differences were found between groups. Significantly greater increases in dominant hip ER (F [1,21] = 5.561, p = .019), nondominant ER (F [1,21] = 7.656, p = .012), dominant total hip rotation (F[1,21] = 7.128, p = .015) and nondominant total hip rotation (F[1,21] = 7.031, p = .015) were found in the TMRG compared to the TWG (Table 5). Statistically significant differences between groups were not found for dominant hip IR (F [1,21] = 2 .276, p = .147) or nondominant hip IR (F[1,21] = 2.561, p = .125); however, these analyses were underpowered (observed power equals 30% and 33% respectively). The effect sizes indicate a medium or large treatment effect (η² > .058) for each of the analyses (Table 6).²⁹

Table 6.

Change in Active Hip Internal and External Rotation From Pre- to Post-intervention Between Groups.

Change from Baseline	Total Motion Release Group (TMRG)	Traditional Warm Up Group (TWG)	p-value	Effect Size (partial eta squared η2)	Observed Power (Post-hoc)
Dominant Hip Internal Rotation (IR)	5.9° ± 4.7°	1.7° ± 7.9°	p = .147	η2 = .102	.301
Dominant Hip External Rotation (ER)	6.27° ± 4.7°	0° ± 7.2°	p = .029	η2 = .218	.612
Dominant Total Hip Rotation	12.2° ± 6.2°	1.9° ± 11.1°	p = .015	η2 = .263	.719
Non Dominant Hip IR	6.7° ± 6.8°	1.5° ± 8.2	p = .125	η2 = .114	.332
Non Dominant Hip ER	4.8° ± 4.6°	-1° ± 4.7°	p = .012	η2 = .277	.749
Non Dominant Hip Total Rotation	11.9° ± 7.6°	1° ± 11.6°	p = .015	η2 = .260	.713

DISCUSSION

The purpose of this study was to observe the effects of the TMR^® unilateral Forward Flexion Trunk Twist (FFTT) and Seated Straight Leg Raise (SLR) on active hip IR and ER when compared to a traditional athletic warm-up in overhead athletes. Post-intervention, participants in the TMRG demonstrated significantly increased dominant hip ER (mean _change = +6.27°), dominant hip total rotational ROM (mean _change = +12.2°), nondominant hip ER (mean _change = +4.8°), and nondominant total hip rotational ROM (mean _change = +11.9°) compared to the TWG. Participants in the TMRG also gained approximately +6° of dominant IR and +5° of nondominant IR, but the between group differences were not statistically significant (Table 6). The lack of significant group differences for increases in IR could be explained by the sample size and moderate effect sizes for each variable (η² = .102, η² = .114, respectively), which resulted in reduced power of the analysis and may suggest that the sample size was too small to identify meaningful group differences that may have been present.³⁰ Overall, the improvement in ROM for all of the measures is clinically meaningful given the effect sizes and MDC values established during pilot testing.²⁷ The ROM improvements, coupled with large between group differences in time to completion (TMRG = 7 minutes, TWG = 25 minutes), suggests TMR^® may be a more efficient and effective intervention strategy than traditional warm-up programs for increasing hip rotational ROM in overhead athletes. Furthermore, when compared to literature on passive ROM changes after static stretching, the results of the current study suggest that active, regionally interdependent interventions produce greater changes in rotational hip ROM.¹⁷

While it is plausible that a number of factors contribute to deficits and alterations in active rotational ROM of the hip, research in the area of post intervention changes in active hip rotational ROM is lacking. It appears that this is the only study examining short-term changes in active hip rotational ROM in healthy overhead athletes following a warm-up protocol. When compared to the available literature, the participants in the current study exhibited relatively normal values for hip IR and ER ROM pre-intervention.^{8,10,11,17,31} For example, when compared to a study of college baseball pitchers by Shimamura et al.,³¹ participants in this study presented with similar ROM values at baseline when measured in the seated position (dominant hip IR = 33° for right handers and 33.6° for left handers; dominant hip ER = 36.9° for right handers and 43.2° for left handers). However, it is important to note that measurement techniques, positions, inclusion of passive and/or active measures, normative values, injury risk, and the relationship between ROM and performance in overhead athletes vary greatly across the literature.^{8,10,11,13,17,31}

Shimamura et al.³¹ and Sauers et al.,¹⁰ for example, measured participants passively in a seated position. In contrast, Van Dillen et al.¹⁴ and Bremner et al.¹⁷ measured passive ROM in a prone position. Ellenbecker et al.¹¹ measured participants’ AROM in a similar prone position, while Li et al.⁸ measured passive ROM in a supine 90/90 position. The current study measured active hip rotation seated at 90/90 with a smartphone inclinometer. When combined, the paucity of literature on the effect of interventions for improving hip IR and ER, the differences in measurement position, type of ROM, and methods utilized make it challenging to draw conclusions or generalize recommendations.

It is likely that interventions designed to increase active hip ROM may be useful in the prevention of future injury in overhead athletes given the findings of previous researchers regarding hip ROM loss and injury in baseball players,^7,8 degenerative joint disease of the hip in javelin throwers,¹² and hip rotational ROM and lumbo-pelvic pain.¹⁴ Furthermore, other researchers suggest that bilateral symmetry in hip rotation should be a normal finding in healthy baseball players.¹¹ It is also plausible that TMR^® based interventions are more effective than static stretching at “ball and socket” synovial joints,^17-20 and may help reduce incidents of lumbo-pelvic pain and dysfunction in overhead athletes. Total Motion Release^® methods, such as the FFTT that include active trunk rotation, more directly impact the hip, lumbo-pelvic complex, and core musculature due to alterations in motor control and strength that do not occur with static stretching. The significant improvement in bilateral hip ER and total hip rotation, along with strong effect sizes suggests the results of our study are likely clinically and practically meaningful. Considering these findings in conjunction with previous research ^18,19 on TMR^®, the incorporation of TMR^® methods may prove useful as part of larger performance readiness and injury prevention strategy in overhead athlete populations by quickly increasing AROM at both the hip and shoulder joints.

POTENTIAL MECHANISMS OF ACTION FOR TOTAL MOTION RELEASE^®

When investigating and utilizing TMR^®, it is important to consider the potential neuromuscular mechanisms of action at work. Irrespective of the TMR^® application method (e.g., contralateral applications, ipsilateral applications, statics holds, repetitions), immediate alterations in motor control and strength may be due to increased neuromuscular and motor neuron activity.²¹ Total Motion Release^® may utilize cross education,²² neural coupling,²³ and the common core hypothesis ²⁴ to act on fascial and muscular tissues, as well as joint positioning via integrated central and peripheral nervous system feedback, creating alterations in strength, coordination, and AROM. It is plausible that the use of TMR^® in the present study functioned on the principles of proximal trunk stability producing distal extremity mobility with the use of the FFTT.¹ As an indirect intervention which avoids directly addressing dysfunction by treating into restriction (i.e., as would typically occur with a joint mobilization or stretching), TMR^® techniques may produce positive changes due to neuro-physiological adaptation. Instead of reinforcing a restricted or dysfunctional pattern, TMR^® may allow for the adaptation of spinal motor neurons via non-threatening movements, which then transfers to the opposite side, or related interdependent regions of the body.²¹

LIMITATIONS & FUTURE RESEARCH

A relatively small sample size (n = 22) and participation by a healthy athletic population makes the generalization of these findings across populations difficult. The examiner and the participants were not blinded as one clinician administered the intervention and collected measurements, and participants could not be blinded without the use of a sham intervention. Long-term ROM changes for either group were also not recorded, thus only short term effects should be considered when interpreting the findings of the current study. While remaining true to TMR^® principles,²⁵ the hip flexion angle and trunk posture of participants in the TMRG were not controlled for during the FFTT, potentially affecting standardization across participants. As a result, it is unknown what effect, if any, hip and trunk flexion angle play in the efficacy of this technique. However, these methods are in agreement with TMR^® guidelines of allowing individuals to determine the motion that best allows them to access end-range of motion in a given movement pattern,²⁵ and are in line with the application of TMR^® in clinical practice.

Although no statistically significant between groups differences at baseline were found for any dependent variable, it is possible that the differences at baseline impacted final results. For example, because the participants in the TWG began with more ROM than the TMRG, a ceiling effect may have limited ROM gains in that group. However, it is important to note that despite participants in TWG having higher ROM at baseline, the TMRG had greater ROM than the TWG in every category post-intervention. Additionally, due to small sample size and randomization, sport and gender differences were not controlled for in this study which may have played a role in differences at baseline. It is also important to note that participants in the study fell within the ROM norms established by the literature for baseball players and overhead athletes.^8,10,11

Additionally, the static stretches included in the TWG in this study were not directed at the hip. In the TWG, participants performed a static stretching protocol that included a seated cross body stretch, a seated upper trapezius stretch, and a side lying sleeper stretch with the arm at 90 degrees of adduction and 90 degrees of shoulder and elbow flexion. Due to the inconclusive nature of static stretching literature, particularly when hip ROM is concerned,¹⁷ the choice of stretches was made in an attempt to mirror the process often undertaken during warm-up by those participating in overhead, upper extremity dominant sports. As a result, static stretching of the hip was purposefully omitted as the dynamic warm-up used in the TWG addressed lower extremity preparedness particularly with the inclusion of trunk rotational lunges and lateral lunges.

Future research should begin to examine time to completion differences of other intervention strategies designed to improve AROM and help guide clinical practice. Investigations into the duration, rate, and magnitude of change over time when utilizing TMR^® are also needed to provide insight into the clinical utility of TMR^®. Total Motion Release^® as a bridge between rehabilitation and performance. Research into the application of TMR^® as a paradigm should be conducted to determine best practices and investigate treatment outcome differences across different populations. For example, the application of TMR^® to maximize improvement in a desired outcome may vary if the technique is used in an injured population to reduce pain compared to a healthy, active population attempting to improve ROM before activity. Another example might assess if specific motions (e.g., rotational motions of the trunk) or application of the full TMR^® assessment and treatment protocol produce different results as suggested per the recommendation of the paradigm creator.²⁵

CONCLUSIONS

The results of this study indicate that TMR^® was more effective at immediately increasing bilateral hip ER and total hip rotation in overhead athletes than a traditionally designed athletic warm-up. Additionally, the TMR^® intervention was completed significantly faster than the traditional warm-up. These results indicate that TMR^® has the potential for use across sports performance professionals as part of warm-up design for improving ROM at the hip in the short term.