Effects of the Kinetic Chain Approach for Scapular Dyskinesis
Condition: Shoulder Impingement Syndrome
MeSH terms: Shoulder Impingement Syndrome
Study type: Interventional

Summary: 
      Volleyball is a highly technical sport which involved powerful overhead movements performed
      repetitively. Shoulder injuries is the third-most commonly injured body part in volleyball,
      with the majority resulting from chronic overuse. Abnormal scapular motions and positions
      relative to the thorax have been linked to various shoulder pathologies, including
      subacromial impingement, rotator cuff tears, and glenohumeral inferior instability. Also,
      Muscular imbalances around the shoulder complex could lead to dyskinesis and resulting in
      shoulder joint injuries (e.g. instability and impingement).

      The concept of "kinetic chain" is coordinated sequencing of the segments. Sequential
      activation of the LE, pelvis and trunk muscles is required to facilitate the forces to be
      transferred appropriately from these body segments to the UE.

      Reeser et al. have identified risk factors for volleyball-related shoulder pain and
      dysfunction. They found volleyball athletes who demonstrated core instability would show
      greater relevance to SICK scapula, and they also more likely to report a history of shoulder
      problems. Sciascia et al. also have reviewed that 49% athletes with posterior-superior labral
      tears showed either decreased hip rotators ﬂexibility or decreased hip abductors strength.
      Consequently, the deficits in kinetic chain segments would resulted in scapula dyskinesis,
      even lead to shoulder girdle dysfunction or injury.

      Therefore, the modern training programs for athletes, especially in overhead players, should
      combine kinetic chain exercises to improve upper- and lower body core strength, sport-speciﬁc
      strength, performance, and prevent injury occurrence or recurrence.

      In consideration of no randomized controlled trials (RCTs) have been performed to determine
      whether kinetic chain exercise would be more effective to conventional scapula training for
      patients with secondary shoulder impingement. The purpose of the study is to investigate the
      effects of kinetic chain management approach (KC) and conventional training of scapula
      dyskinesis (CT) in volleyball athletes with scapular dyskinesia. The investigators
      hypothesized that KC group would be more effective in self-reported pain, and their scapula
      would become more stable during movement task (arm-lifting and spiking) after a 4-week
      training program than CT group.
    

Detailed description: 
      Volleyball is a highly technical sport which involved powerful overhead movements performed
      repetitively. Shoulder injuries is the third-most commonly injured body part in volleyball,
      with the majority resulting from chronic overuse. Abnormal scapular motions and positions
      relative to the thorax have been linked to various shoulder pathologies, including
      subacromial impingement, rotator cuff tears, and glenohumeral inferior instability. Also,
      Muscular imbalances around the shoulder complex could lead to dyskinesis and resulting in
      shoulder joint injuries (e.g. instability and impingement).

      The concept of "kinetic chain" is coordinated sequencing of the segments. Sequential
      activation of the LE, pelvis and trunk muscles is required to facilitate the forces to be
      transferred appropriately from these body segments to the UE.

      One previous study have identified risk factors for volleyball-related shoulder pain and
      dysfunction. They found volleyball athletes who demonstrated core instability would show
      greater relevance to SICK scapula, and they also more likely to report a history of shoulder
      problems. Another study also have reviewed that 49% athletes with posterior-superior labral
      tears showed either decreased hip rotators ﬂexibility or decreased hip abductors strength.
      Consequently, the deficits in kinetic chain segments would resulted in scapula dyskinesis,
      even lead to shoulder girdle dysfunction or injury.

      Therefore, the modern training programs for athletes, especially in overhead players, should
      combine kinetic chain exercises to improve upper- and lower body core strength, sport-speciﬁc
      strength, performance, and prevent injury occurrence or recurrence.

      In consideration of no randomized controlled trials (RCTs) have been performed to determine
      whether kinetic chain exercise would be more effective to conventional scapula training for
      patients with secondary shoulder impingement. The purpose of the study is to investigate the
      effects of kinetic chain management approach (KC) and conventional training of scapula
      dyskinesis (CT) in volleyball athletes with scapular dyskinesia. The investigators
      hypothesized that KC group would be more effective in self-reported pain, and their scapula
      would become more stable during movement task (arm-lifting and spiking) after a 4-week
      training program than CT group.

      The investigators plan to recruit 50 volleyball athletes. The sample size will be determined
      by previous studies and our future pilot study. It will be based on a significance level of
      0.05, and a power of 0.80 to detect a difference on scapular upward rotation of 4° with a
      standard deviation of 4.5°. Based on these criteria, at least 21 participants with secondary
      shoulder impingement syndrome will be required in each group. To account for a withdrawal
      rate of 10%, participants will be included at least in each group. They will mainly be
      recruited from the universities in Taipei. A physical therapist will first evaluate the
      subject whether they are diagnosed of scapular dyskinesia. For subjects' evaluation, physical
      examination will include observation, palpation, selective tissue tension test (STTT),
      impingement sign test (Neer's, Hawkins-Kennedy), and scapular motor control test (flexion,
      abduction, external/internal rotation). Moreover, the investigators will design a check list
      to confirm whether they meet the inclusion/exclusion criteria. Patients who meet the criteria
      will enroll in this study, and then each of them will randomly be divided into two training
      groups.

      The self-reported worst pain in the previous week will be measured using the visual analog
      scale (VAS; maximum score = 10 cm). The VAS is a self-reporting tool used to assess the level
      of pain of patients with shoulder pain due to scapular dyskinesis. Patients will be asked to
      draw a mark along a 10-cm line that indicates the amount of pain they are experiencing
      relative to a score of 0, indicating no pain, and a score of 10, indicating the most pain
      (worst). On the VAS, the investigators will choose to measure the "worst" pain, because
      previous studies suggested that it was more reliable than measuring "usual" pain.

      LIBERTY™ electromagnetic tracking system (Polhemus, Colchester, VT, USA) was used to collect
      three-dimensional kinematic (3D) data during arm-lifting task and spiking task at a sampling
      rate of 120 Hz, and the software Motion Monitor® (Innovative Sport Training, Inc., Chicago.
      IL. USA) was used to analyze the data. The main measurement of shoulder kinematics include
      scapular upward/downward rotation, internal/external rotation, and anterior/posterior
      tilting. A stylus was used to digitize the bony landmarks for defining the anatomical
      coordinate system. The methods for this measure have been described previously.

      For collecting muscle activation data, the investigators used surface electromyography (sEMG,
      TeleMyo 2400 G2 Telemetry; Noraxon USA, Inc., USA) to collect scapular muscles' activation
      during arm-lifting task. The investigators will measure the muscle activities of SA, UT, and
      LT. The electrodes will be placed according to previous studies, and will be positioned in
      parallel to the direction of the muscle ﬁbers.

      For exercise performance assessment during spiking task, the investigators measured scapular
      kinematics consistency. The spiking task is consisted of total 30 rep of spiking, including
      initial 5 trials, 20 rep of fatigue, and last 5 trials. The investigators will conduct a
      pilot study to confirm the measurement which the investigators designed with enough
      reliability and validity.

      The data of each outcome measures would collect at before (PRE measurement) and after 4-week
      intervention (POST measurement) except for self-reported pain (VAS), which would be collected
      at each end of week in addition. If the subject could not complete PRE and/or POST
      measurement, the investigators will note the reason which makes him/her unable to finish the
      whole trials, such as pain, instability or any discomfort.

      Statistical analysis will be done on intention-to-treat basis using SPSS software (version
      20; formerly SPSS Inc, now IBM Corporation, Armonk, NY). Missing data will be replaced using
      a conservative method with the last score carried forward. The independent t test or
      Chi-square test will be used for baseline demographic data. Descriptive statistics will
      include mean, standard deviation, and 95% confidence interval values, and the investigators
      will calculate 2 × 2 analyses of variance (ANOVAs; group × time; p < 0.05) for each outcome
      variables. Signiﬁcant differences revealed by the ANOVA will be further examined using
      Bonferroni post hoc analysis. The alpha (α) level will be set at 0.05.
    

Intervention name(s): KC group; CT group
Intervention type(s): Other; Other
Intervention description(s): 1st week: each 10 rep/set, 3 set/day. PNF scapular pattern: posterior depression (Combination of isotonic, COI), Ball modified prone Cobra, Ball prone V-raise, Ball prone row, Ball side plank, Ball one-leg bridging
2nd week: each 10 rep/set, 3 set/day. Half sit-up with rotation to left/right, Side plank with ER, Prone extension with rotation to left/right, Bilateral one-leg squat with flexion, Squat to row
3rd week: 5 rep/set, 3 set/day (sling exercise). Prone shoulder protraction, Supine shoulder retraction, Side-lying hip ABD/ADD, Supine pelvic lift, Prone bridging
4th week: each 10 rep/set, 3 set/day. Lateral lunges with shoulder ABD/ER, Lunge with trunk rotation, Forward punch plus with serape effect, Spiking exercise, One-quarter vertical squat jump; 1st week: each 10 rep/set, 3 set/day. PNF scapular pattern: posterior depression (Combination of isotonic, COI), Knee push up plus, Modified prone Cobra, Prone V-raise, Prone row, Side-lying ER
2nd week: each 10 rep/set, 3 set/day. Supine punch, Prone horizontal ABD, Prone V-raise, Prone row, Side-lying ER
3rd week: each 10 rep/set, 3 set/day. Sitting chest press, Sitting ABD in scaption, Sitting overhead press, Long-sitting resisted extension, Sitting ER
4th week: each 10 rep/set, 3 set/day. Standing horizontal pull-apart, Standing retraction plus ER, Standing resisted extension, Ball pushed on wall and controlled rolling, Wall push-up
Other intervention name(s): Exercise therapy; Exercise therapy
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: A randomized controlled trial (RCT) with two treatment groups, kinetic chain management approach (KC) and conventional training of scapula dyskinesis (CT).
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Volleyball; Shoulder impingement; Scapular dyskinesis; Kinetic chain