Head impact differences in blind football between Rio 2016 and Tokyo 2020 Paralympic Games: video-based observational study.

OBJECTIVE: In Tokyo 2020 Paralympic Games, there were the rule and goal size changes at the blind football competition. This study aimed to compare the scoring and head impact characteristics during blind football competition between the Rio 2016 and Tokyo 2020 Paralympic Games using the official videos. DESIGN: Video-based observational study. PARTICIPANTS: In total, 36 blind football (men's football 5-a-side) game videos were obtained from the official International Paralympic Committee. PRIMARY AND SECONDARY OUTCOME MEASURES: Head impact was defined as the sudden contact of any object with the head. Videos were analysed to assess the number of scores and head impacts along with their corresponding details (ie, round, playing phase, scoring situation, impact situation, occurrence area, impact object, head impact site, fall and foul). RESULTS: The total number of goals scored at the Tokyo 2020 Paralympic Games was nearly double that at the Rio 2016 Paralympic Games. Regarding head impacts, a total of 2036 cases (Rio 2016, n=1105; Tokyo 2020, n=931) were evaluated. Significant differences were observed in head impact characteristics between the Rio 2016 and Tokyo 2020 Paralympic Games among seven outcomes (round, scoring situation, impact situation, occurrence area, impact object, site of head impact and fall). CONCLUSIONS: Compared with the Rio 2016 Paralympic Games, the Tokyo 2020 Paralympic Games showed an increase in the number of points scored and different head impact characteristics.

The Features of Foot Morphology and Intrinsic Foot Muscle Property in Adolescent Swimmers: An Ultrasound-Based Study.

This cross-sectional study aimed to investigate the relationship between foot shape and intrinsic foot muscles (IFMs) in adolescent swimmers compared with other athletes. Foot morphology of swimmers was compared with other athletes of comparable age and a competition level (n = 32 [64 feet]; a total of 64 feet; 128 feet in two groups). Foot morphology and variables of IFMs were measured using a three-dimensional foot scanner and an ultrasound imaging system, respectively. Multiple linear regression analysis with forced entry was performed to clarify the association of the thickness and the cross-sectional area (CSA) of IMFs with the navicular height in both sitting and standing positions. Navicular height in a standing position, the thickness of the abductor hallucis (AbH) and the flexor digitorum brevis (FDB), as well as the CSA were significantly lower in swimmers compared with other athletes (p < 0.05). A larger CSA for the flexor hallucis brevis (FHB) was observed in swimmers than in other athletes (p < 0.01). The navicular height of swimmers in sitting and standing positions was positively correlated with the thickness and the CSA of the FHB and the FDB (p < 0.05). Multiple regression analysis showed that navicular height was associated with the CSA of the FDB in both sitting and standing positions (ß = 0.395; p < 0.002, ß = 0.201; p < 0.018). This study showed that the navicular height of elite adolescent swimmers was lower than that of other athletes. Furthermore, the swimmers' high navicular height was associated with the CSA of the FDB, suggesting that the FDB might be more involved in the formation of the medial longitudinal arch than the AbH.

Comprehensive inpatient rehabilitation for elite athletes after anterior cruciate ligament reconstruction.

[Purpose] The authors' institute offers a comprehensive inpatient approach to rehabilitation after anterior cruciate ligament reconstruction surgery, providing nutritional and psychological support in addition to exercise and physical therapy. This study aimed to determine the outcomes of athletes undergoing this comprehensive rehabilitation program and to compare the outcomes of bone-patellar tendon-bone and semitendinosus/gracilis autograft recipients. [Participants and Methods] Elite athletes who underwent comprehensive inpatient rehabilitation at the authors' institute for at least two weeks after anterior cruciate ligament reconstruction were mailed a questionnaire. Their recovery levels, which were measured against preinjury performance, and secondary anterior cruciate ligament injury rates, were evaluated and compared according to graft type. [Results] Valid responses from 45 athletes were analyzed (bone-patellar tendon-bone [n=12]; semitendinosus/gracilis [n=33]). The frequency of return to preinjury activity levels and secondary anterior cruciate ligament injury were comparable between bone-patellar tendon-bone and semitendinosus/gracilis graft recipients. A greater proportion of athletes returned to preinjury activity levels, while a lower percentage experienced re-rupture compared to previous studies. [Conclusion] A comprehensive rehabilitative approach after anterior cruciate ligament reconstruction may contribute to improved postoperative performance irrespective of graft type. Objective evaluations are needed in the future to clarify the benefits of specific rehabilitative approaches.

Head Impact in Blind Football During the Tokyo Paralympics: Video-Based Observational Study.

ABSTRACT: Head impacts during blind football are common and have high injury rates; however, their characteristics and impact are still underreported. We compared head impact characteristics in blind football players with and without falls on all 18 official blind football match videos from the Tokyo 2020 Paralympic games. The rate of head impacts with falls was significantly higher in the preliminary phase, offense phase, and during dribbling. Significant differences in the region of the head impacted were also observed among the impact subjects/objects. The findings in this study would contribute to the development of injury prevention measures to minimize head injuries from head impact in blind football.

Characteristics of Wheelchair Basketball Falls During the Tokyo 2020 Paralympics by Sex and Physical Impairment Classification: A Video-Based Observational Study.

OBJECTIVE: The aim of the study is to evaluate the fall characteristics of wheelchair basketball players by sex and impairment classification using the official videos of the Tokyo 2020 Summer Paralympic Games. DESIGN: This was a video-based observational study. In total, 42 men's and 31 women's wheelchair basketball game videos were obtained from the official International Paralympic Committee. The videos were analyzed to assess the number of falls, playing time of the fall, playing phase, contact, foul judgment, fall location/direction, and the body part that first impacted the floor. RESULTS: A total of 1269 falls (men, n = 944; and women, n = 325) occurred. The analysis of men demonstrated significant differences in rounds, playing phase, location of fall, and body part first impacted. Women demonstrated significant differences in all categories except in rounds. Comparisons by functional impairment showed different trends for men and women. CONCLUSIONS: The detailed observation of videos suggested that men are more likely to have dangerous falls. There is a necessity for discuss the prevention measures based on sex and impairment classification.

Characteristics of Falls Among Men's Wheelchair Rugby Players in the Rio 2016 and Tokyo 2020 Summer Paralympic Games: A Video Analysis.

Wheelchair rugby is a contact sport in which falls are common and injury rates are high, yet the characteristics of the falls are still under-reported. We investigated the fall characteristics of men's wheelchair rugby players by functional classification, using all 36 official match videos from the Rio 2016 and Tokyo 2020 summer Paralympic Games. The videos were analyzed to evaluate the number of falls, playing time when the fall occurred, playing phase (offense or defense), contact with other players, foul judgement, direction of the fall, and the body part first in contact with the floor. All 182 men's wheelchair rugby players (Rio 2016, 94; Tokyo 2020, 88) were classified as low-point players or high-point players depending on their functional classification. A total of 200 falls were detected, 27 (13.5%) for low-point players and 173 (86.5%) for high-point players. Significant differences were noted between low-point players and high-point players in the direction of the fall and body part first in contact with the floor. High-point players had more falls in the forward and left-right directions, whereas low-point players were characterized by a higher percentage of falls in the left-right and backward directions. Additionally, high-point players landed on the floor with their hands with high frequency, whereas low-point players landed with their elbows and shoulders more often. Our findings suggest the significance of devising measures to prevent falls during men's wheelchair rugby games according to their functional classification.

Analysis of wheelchair falls in team sports at the Paralympic Games: video-based descriptive comparison between the Rio 2016 and Tokyo 2020 games.

OBJECTIVES: To identify the fall characteristics of athletes in wheelchair rugby and wheelchair basketball during the Tokyo 2020 Paralympic Games and descriptively compare these with those of the Rio 2016 Paralympic Games. DESIGN: Cross-sectional analysis. PRIMARY AND SECONDARY OUTCOME MEASURES: We obtained video footage from the International Paralympic Committee of the Tokyo 2020 Paralympic Games that included 8 teams from each of the 18 wheelchair rugby and 10 wheelchair basketball games (men and women). The data were analysed to evaluate the number of falls, class difference (low or high pointer), time of play during the fall, phase of play, contact with other athletes, fall direction, fall location and the body part that first contacted the floor during the fall. These data from the Rio 2016 and Tokyo 2020 games were compared. RESULTS: Overall, 430 falls (rugby, 104; men's basketball, 230 and women's basketball, 96) occurred (average per game ±SD: 5.8±3.1, 23.0±5.4 and 9.6±5.0, respectively). Significant differences in class, direction, fall location and body part point of contact between the three sports were observed. In wheelchair rugby, falls occurred mainly in high pointers and tended to be more lateral due to contact. In wheelchair basketball, falls occurred more in female high-pointers and in male low pointers, with more forward falls due to forward contact. Unlike in the Rio 2016 games, no difference between the events based on the presence or absence of contact was observed in the Tokyo 2020 games. CONCLUSIONS: The number of falls increased in Tokyo 2020 compared with Rio 2016, with no significant difference in the characteristics of falls between the Rio 2016 and Tokyo 2020 games. Only in men's wheelchair basketball, the number of falls in low pointers significantly increased in the Tokyo 2020 games when compared with that in the Rio 2016 games.

Does the sesamoid rotation angle change differently in subjects with hallux valgus considering foot position during assumed walking? A pilot study.

Hallux valgus (HV) entails changes in the alignment of the rotating sesamoids and a shift of the abductor hallucis muscle (ABH) in the plantar direction, decreasing the abductor force. Load on the foot while walking may change the sesamoid rotation angle (SRA). Nevertheless, no study has investigated the relationship between the change in SRA during assumed walking and ABH muscle size. The aim of our study was to examine the changes in SRA at different foot postures assumed to generate skeletal alignments during walking and muscle size of the ABH in participants with HV and to discuss the association between the change in the SRA and cross-sectional area (CSA) of the ABH. Thirteen female participants were recruited and divided into the HV and non-HV groups according to the HV angle. The SRA and cross-sectional area of the ABH were measured using B-mode ultrasound. The SRA was measured under four conditions; sitting, standing, mid-stance, and pre-swing posture. The CSA was assessed in the supine position. In all postures, the SRA increased more in the HV group than in the non-HV group (p < 0.05). The change in the SRA at the pre-swing posture was greater in the HV group than in the non-HV group (p < 0.05). The change in the SRA at pre-swing posture negatively correlated with the CSA of the ABH in the HV group (r = -0.554, p < 0.05). In the HV group, increasing the load on the forefoot enhanced the sesamoid rotation. Abductor torque on the ABH decreased with ABH displacement as the sesamoids moved laterally in the pre-swing. Repeated walking increased sesamoid rotation and led to HV progression. Therefore, it may be beneficial to use an orthosis or arch pad that corrects pronation of the metatarsal with the rotation of the sesamoids.

Biomechanics of Double Poling in Paralympic Cross-Country Skiing-A Cross-Sectional Study Comparing the Standing and Sitting Positions in Healthy Male Subjects.

Background and Objectives: Double poling is an important fundamental skill required for cross-country skiing in able-bodied athletes and in those with physical disabilities. Meanwhile, the performance improvement and injury prevention related to double poling requires a thorough assessment, whereas the scapular and shoulder kinematics in different postural conditions remain to be clarified. The main purpose of this study was to evaluate the biomechanics during cross-country ski double poling in the standing and sitting positions. Materials and Methods: Eleven participants underwent kinematic assessments of the shoulder girdle during double poling on a ski ergometer with an electromagnetic tracking device. The cycle rate, stroke length, stroke speed, thorax motion relative to pelvis, scapular motions relative to thorax, humeral motions relative to thorax, and humeral motions relative to scapula were calculated for five double-poling cycles. Results: In the sitting position, the angles of humerothoracic elevation were 18 degrees larger and glenohumeral elevation 13 degrees larger than in the standing position at the upward point and range of motion. Conclusions: The study revealed that double poling in the sitting condition increased the humerothoracic and glenohumeral elevation angle to secure the poling margin. If these are excessive, there is a risk of shoulder injuries such as subacromial impingement.

Shoulder muscle activation during scapular protraction exercise with arm rotation.

BACKGROUND: The role of the serratus anterior is to maintain scapular stability. To strengthen this muscle, scapular protraction exercises are typically performed. Although the angle of arm rotation leads to changes in shoulder muscle activation, the arm rotation position is not normally determined. OBJECTIVE: To investigate if scapular muscle activations were changed by combining arm external rotation during scapular protraction exercises. METHODS: Thirty-four healthy men were enrolled in this study. Participants were instructed to perform scapular protraction exercises at 90∘ and 120∘ of shoulder flexion while in the standing and supine positions. Two different arm rotation angles were used: the thumb-up position (neutral position) and the maximum arm external rotation (ER) position. The percentages of maximum voluntary contractions (%MVCs) were measured, and %MVCs in the neutral and arm ER positions were compared. RESULTS: Muscle activities of the middle serratus anterior (MSA) and lower serratus anterior (LSA) in the arm ER position were significantly higher than those in the neutral position during all tasks. The highest MSA and LSA positions were observed with the arm ER position of 120∘ while standing. CONCLUSIONS: Scapular protraction exercises with arm ER resulted in a higher serratus anterior activity.

The Relationship between Modified Short Physical Performance Battery and Falls: A Cross-Sectional Study of Older Outpatients.

The Short Physical Performance Battery (SPPB) is a physical fall-risk screening tool and predictor of adverse health effects for the older. Its limited use in Japan is due to the relative ease for high-functioning older adults to achieve perfect scores. Japanese researchers thus created a community-based SPPB (SPPB-com). This study investigated whether the SPPB-com score can distinguish between older patients classified as "fallers" and "non-fallers." Participants comprised 185 older outpatients aged 65 and above who self-reported their history of accidental falls and relevant physical activity. Fall risk was assessed using SPPB and SPPB-com. Handgrip strength, maximum isometric knee extensor strength, and maximum walking speed were measured as physical functions. Multivariate logistic regression and receiver-operating characteristic analyses determined criteria indicating faller status. Fallers were older and had lower physical function, physical activity, SPPB, and SPPB-com scores than non-fallers. Multivariate logistic regression analysis showed SPPB (OR 0.76, 95% CI 0.59-0.99, p = 0.045) and SPPB-com (OR 0.63, 95% CI 0.45-0.87, p = 0.005) scores were both independently associated with prior falls. The SPPB-com score may function as a fall-risk assessment tool for older outpatients, and its combined use with SPPB can increase the accuracy and precision of distinction between fallers and non-fallers.

Tensiomyographic Neuromuscular Response of the Peroneus Longus and Tibialis Anterior with Chronic Ankle Instability.

This study aimed to investigate the muscle contractile response of the peroneus longus (PL) and tibialis anterior (TA) in groups with and without chronic ankle instability (CAI) using tensiomyography. Twenty-three adults, 12 with CAI and 11 healthy participants, participated in this study. All subjects underwent a tensiomyographic assessment of the PL and TA to measure delay time, contraction time and maximal displacement. The ankle evertor and invertor normalized peak torques, maximum work done and muscle thickness of the PL and TA were calculated. The delay time and contraction time of the PL in the CAI side were significantly higher than those in the healthy group (p < 0.05); however, no significant difference could be detected in the TA between groups. Furthermore, there was no significant difference in the normalized peak torques, maximum work done and muscle thickness of the PL and TA between groups. The CAI side demonstrated a delayed muscle contractile response of the PL when compared with the healthy group although there was no difference in muscle strength and muscle size. Clinicians should consider the muscle contractile response of the PL for rehabilitation of the ankle evertor with CAI.

The infraspinatus muscle activity during pitching motion in baseball players with shoulder instability.

BACKGROUND: Shoulder microinstability is often overlooked, which can be problematic, especially in overhead athletes. The slipping phenomenon is defined as posterior or lateral sliding of the humeral head in an elevated arm. When the shoulder is close to the end range of stability, the infraspinatus is highly activated and keeps the shoulder in the glenoid cavity. This study aimed to examine the characteristic physical function and infraspinatus activity during the pitching motion in baseball pitchers with shoulder instability. METHODS: Twenty-one male baseball pitchers participated and were divided into 2 groups based on radiograph findings at zero position: slipped (group S) and nonslipped (group N) groups. Physical function using Hara test and infraspinatus muscle activity during pitching were evaluated. RESULTS: The infraspinatus muscle activity during the acceleration phase was significantly greater in group S (59.5 ± 33.0%MVC) than in group N (33.0 ± 16.9%MVC) (P < .05). Positive rate of the Hara test in group S was significantly high in the loose test and elbow push test. CONCLUSIONS: This study shows that baseball pitchers with slipping phenomenon have capsular laxity and scapular instability that indicate high infraspinatus muscle activity during the acceleration phase. Therefore, repetitive pitching with hyperactivity of the infraspinatus on the slipping shoulder may cause fatigue and dysfunction.

Functional Predictors for Home Discharge after Hip Fracture in Patients Living in Sloped Neighborhoods or Islands: An 8-Year Retrospective Cohort Study.

Functional predictors of home discharge after hip fractures have been widely reported; however, no study has considered the geographical features surrounding patients' homes. This study aimed to identify home discharge predictors and determine the cutoff points required for home discharge of patients living in sloped neighborhoods or islands. A total of 437 postoperative hip fracture patients were included and classified into the flat, slope, and island groups according to their residential area before the fracture. Multivariate logistic regression analysis was used to identify significant home discharge predictors, and receiver-operating characteristic analysis to calculate cutoff values. In all the groups, the functional independence measure-motor score was a significant home discharge predictor, with cutoff values of 69 for the flat group and 65 points for the slope and island group. In the slope group, the 6-minute walking distance (odds ratio, 1.02; 95% confidence interval, 1.01-1.04) and revised Hasegawa dementia scale score (odds ratio, 1.06; 95% confidence interval, 1.01-1.12) were also identified as predictors, with cutoff values of 150 m and 18 points, respectively. The outcomes required for home discharge after hip fracture differ depending on the neighborhood terrain, especially for patients living in areas with many slopes and stairs.

Analysis of team-sport wheelchair falls during the Rio 2016 Summer Paralympic Games: a video-based cross-sectional observational study.

OBJECTIVES: To present the fall characteristics of athletes playing wheelchair rugby (WR) and wheelchair basketball (WB) using official videos from the Rio 2016 Paralympic Games and compare the key fall characteristics among the team wheelchair sports event. METHODS: Eighteen WR and 10 WB game videos for men (MWB) and women (WWB), including 8 teams per sport, were obtained from the official International Paralympic Committee of the Rio 2016 Paralympic Games. The videos were analysed to assess the number of falls, playing time of fall, playing phase, contact with other athletes, the direction of the fall and the body part first in contact with the floor during the fall. RESULTS: In total, 359 falls (96 for WR, 172 for MWB and 91 for WWB) occurred with a mean of 5.3, 17.2 and 9.1 falls per match, respectively (p<0.05). Significant differences among the three sports were detected in the playing time (p=0.011), presence of contact (p=0.037), direction (p<0.001) and body part first in contact with the floor (p<0.001). For WR, the falls were primarily lateral and caused by contact, occurring in the second half of the match. WB falls tended to be in the first half for women and the second half for men. Most falls were contact falls in the forward direction. CONCLUSION: By observing the situational details, we described that a number of falls due to contact occurred during these team sports events, especially MWB. In addition, each sport exhibited characteristics attributable to differences in gender, degree of impairment and game rules. The directions of the falls and characteristics of the affected body parts indicate differences in impairments depending on the sport. A fall to the side or back may indicate a risk of injury.

Comparative study of the differences in shoulder muscle activation according to arm rotation angle.

BACKGROUND: Scapular muscle exercise is important for patients with shoulder disorders. Distal variance leads to changes in shoulder muscle activation. Here, we aimed to determine whether scapular muscle activation is affected by different arm rotation angles. METHODS: Overall, 30 healthy men participated in this study. The subjects were asked to keep their arms at 120 degrees of shoulder flexion while holding a 1.0-kg dumbbell in palms down (pronation) and palms up (supination) positions. Electromyography was used to measure anterior, middle, posterior deltoid, serratus anterior, upper, and lower trapezius muscle activation during the task. The muscle activations of each shoulder were compared between the pronation and supination positions. RESULTS: Anterior deltoid and serratus anterior activations were significantly higher in supination than in pronation (p < .05). Alternatively, posterior deltoid and lower trapezius muscles were significantly more activated in pronation than in supination (p < .05). CONCLUSION: Scapular muscle activation changed with arm rotation angle. Arm rotation angle should be assessed to estimate scapular muscle activation during exercise and motion analysis in clinical practice.

Ultrasonographic Evaluation of the Shoulders and Its Associations with Shoulder Pain, Age, and Swim Training in Masters Swimmers.

Background and objectives: The long head of the biceps (LHB) and rotator cuff tendinopathy is the major cause of shoulder pain in competitive swimmers. The risk of tendinopathy increases with aging; however, the structural changes of LHB and rotator cuff in populations of masters swimmers have not been well examined. The purpose of this study was to investigate the prevalence of ultrasonographic abnormalities of the shoulders in masters swimmers, and the association of pain, age, and swim training with structural changes in this population. Materials and Methods: A total of 60 subjects participated in this study, with 20 masters swimmers with shoulder pain, 20 asymptomatic masters swimmers, and 20 sex- and age-matched controls. All swimmers completed a self-reported questionnaire for shoulder pain, their history of competition, and training volume. Each subject underwent ultrasonographic examination of both shoulders for pathologic findings in the LHB tendon, rotator cuff (supraspinatus (SSP) and subscapularis (SSC)) tendons, and subacromial bursa (SAB) of both shoulders and had thickness measured. Results: The prevalence of tendinosis (LHB, 48.8%; SSP, 17.5%; SSC, 15.9%), partial tear (SSP, 35.0%), and calcification (SSC, 10.0%) were higher in swimmers than in controls. LHB and SSP tendinosis were associated with shoulder pain. Older age and later start of competition were associated with an increased risk of LHB tendinosis and SSC calcification. Earlier initiation of swimming and longer history of competition were associated with an increased risk of SSP and SSC tendinosis. The thicker SSP tendon significantly increased the risk of tendinosis and partial tear. Conclusions: A high prevalence of structural changes in the rotator cuff and biceps tendons in masters swimmers reflects the effect of shoulder symptoms, aging, and swim training.

Effect of 4-week cyclic stretching program on muscle properties and physical performance in healthy adult men.

BACKGROUND: The short-term effect of cyclic stretching (CS) has been found to decrease muscle hardness and improve physical performance. However, the long-term effect of CS program was unclear. This study investigated the long-term effect of CS program on muscle properties and physical performance. METHODS: Eighteen healthy men participated in this study. The participants were assigned randomly to either the CS or control group (9 participants in each group) to conduct 2 min CS of the plantar flexor muscles 5 times a week for 4 weeks. Before and after intervention, the gastrocnemius medialis muscle hardness, muscle-tendon joint (MTJ) angle, and MTJ displacement (ΔMTJ) were measured as indices of muscle properties. In addition, the maximum range of motion of ankle dorsiflexion (ROM max), normalized maximum peak torque of plantar flexor (NPT), vertical jump height, and dynamic postural stability, dynamic postural stability index (DPSI) were measured as indices of physical performance. RESULTS: The CS program was found to significantly decrease muscle hardness and increase vertical jump height and ROM max, but not to change the MTJ angle, ΔMTJ, NPT, and DPSI. CONCLUSIONS: The results of our study suggested that long-term CS program was effective in decreasing muscle hardness and increasing vertical jump height.

Quantity and quality of the peroneus longus assessed using ultrasonography in leg with chronic ankle instability.

[Purpose] Muscle quantity (e.g., cross-sectional area) and quality (e.g., muscle adipose tissue), which are muscle strength determinants, can be assessed using ultrasonography. The study aimed to investigate the changes in the quantity and quality of the peroneus longus and evaluate evertor strength in legs with chronic ankle instability (CAI). Furthermore, the associations among cross-sectional area, echogenicity, evertor strength, and frequency of ankle sprain were examined. [Participants and Methods] Nine males with CAI in unilateral legs were the voluntary participants in this study. The cross-sectional area of the peroneus longus, echogenicity, and evertor strength were measured for all the participants on the sides with CAI and that without. [Results] No significant difference in cross-sectional area was observed between the sides. Significant differences in echogenicity (higher on the CAI side) and evertor strength (lower on the CAI side) were observed between the sides. In addition, a moderate correlation was observed between echogenicity and increased sprain frequency on both sides. [Conclusion] Muscle adipose tissue increased, evertor strength decreased, and the cross-sectional area remained unchanged on the CAI side. The study results suggested that muscle adipose tissue increases with increasing frequency of ankle sprain.

Effect of Whole-Body-Vibration Training on Trunk-Muscle Strength and Physical Performance in Healthy Adults: Preliminary Results of a Randomized Controlled Trial.

CONTEXT: Whole-body-vibration (WBV) stimulus equipment has been used as a new training method for health promotion. Its use in the clinic has expanded to the field of sports and rehabilitation for disabled patients. WBV training is rapidly gaining popularity in health and fitness centers as an alternative method for improving muscle performance. Acute positive effects of WBV have been shown on lower-extremity muscle power and vertical-jump ability; however, there have not been any studies focusing on the long-term effects of WBV for trunk muscle and dynamic balance. OBJECTIVE: To investigate the effects of an 8-wk program of WBV in combination with trunk-muscle training on muscle performance in healthy, untrained adults. DESIGN: Laboratory-based, repeated-measures study. SETTING: University laboratory. PARTICIPANTS: 20 healthy university men. INTERVENTION: Participants were randomly assigned to a WBV or non-WBV group. The WBV group performed a trunk-muscle-training program in combination with WBV; the non-WBV group performed the same muscle-training program without WBV for 8 wk. MAIN OUTCOME MEASURES: In the pre- and posttraining period, the participants were evaluated using the Functional Movement Screen (FMS), Y Balance Test (Y-test) (anterior, posteromedial, and posterolateral reach), trunk-muscle isometric strength (flexor, extensor, and flexor:extensor ratio), squat jump, and countermovement jump. RESULTS: The WBV group had greater improvement than the non-WBV group in both trunk-flexor muscle strength (P = .02) and the Y-test (anterior reach) (P = .004) between pre- and posttraining. CONCLUSION: Adding WBV to a trunk-muscle-strengthening program may improve trunk-flexor isometric strength and anterior reach during the Y-test more than training without WBV. The WBV protocol used in this study had no significant impact on FMS scores, squat jumping, countermovement jumping, trunk-extensor isometric strength, or trunk flexor:extensor ratio.