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Rauseo, ML, Feairheller, DL, LaRoche, DP, and Cook, SB. Acute effect of dynamic and gluteal resistance exercise warm-up protocols on lower-extremity jump landing mechanics in college-aged females. J Strength Cond Res 38(2): 259-265, 2024--Inadequate neuromuscular control of the femur by the glutealmusculature is associated with noncontact and overuse injuries to the knee. Acute bouts of resistance exercises targeting the gluteal musculature can be prescribed as part of a warm-up protocol with the goal of improving subsequent neuromuscular control and performance. The purpose of this study was to determine the effect that a warm-up protocol including moderate-intensity gluteal resistance exercises (GRE) has on single leg jump landing biomechanics. Seventeen healthy, college-aged, recreationally active females (mean6SD; age521.461.9 years; height5166.965.7 cm; body mass562.567.4 kg) performed 3 single leg hop trials per leg after completing no warm-up (CON), a dynamic warm-up (DWU), and a dynamic warm-up with gluteal resistance exercises (DWU + GRE) across 3 laboratory visits. Lower extremity kinetic and kinematic variables were assessed during single leg hops from the point of initial foot contact to deepest knee flexion. Biomechanical differences between dominant and nondominant limb landings were also assessed. Dominant limb hip internal rotation angle after DWU + GRE (2.03 6 9.92°) was significantly greater (p # 0.05) compared with CON (23.36 6 7.74°). Peak knee adduction moment (56.8%), peak knee flexion angle (5.7%), and peak knee external rotation angle (17.0%) were significantly greater (p # 0.017) in the dominant limb, compared with the nondominant limb, across warm-up protocols. The combined DWU + GRE warm-up protocol did not have a substantial impact on landing biomechanics. Clinicians prescribing GRE before activity should not expect significant changes in movement patterns after a single bout. [ABSTRACT FROM AUTHOR]

The purpose of this research was to compare the hip adduction and abduction relative strength, adduction-to-abduction strength ratio (ADD:ABD), and interlimb asymmetries of ice hockey athletes between the typically used bilateral position and 3 unilateral positions in joint-specific angles (0°, 25°, and 50° of hip abduction) relevant to an ice hockey stride. A secondary purpose was to explore any relationships between these measures and hip and groin noncontact injuries, and self-reported pain and disability. Twenty-five semiprofessional male ice hockey athletes (26.7 ± 6.7 years) were assessed for hip abduction range of motion (ROM), hip adduction and abduction relative strength, and completed the Copenhagen Hip and Groin Outcome Score (HAGOS) questionnaire. Within-subjects repeated-measures analysis of variance revealed a significant effect for the assessment position for adduction (F1,24 = 52.4, p < 0.01) and abduction relative strength (F1,24 = 152.1, p < 0.01), ADD:ABD (F1,24 = 38.9, p < 0.01), and the interlimb asymmetries for each of these variables (F1,24 = 9.8-12.3; p < 0.01), with large strength differences observed between the bilateral assessment and all unilateral assessment positions for adduction and abduction relative strength. In addition, 4 athletes experienced a noncontact hip or groin injury within 1 month after testing, and when compared with the rest of the cohort (n = 21) with Welch's t-tests, demonstrated significantly reduced hip abduction ROM (mean difference [MD] = -8.4 ± 2.5°; p < 0.01), sport subscale score for the HAGOS questionnaire (MD = -33.9 ± 7.1; p < 0.01), and a decline in hip adduction relative strength in the unilateral position of 50° compared with the position of 25° hip abduction (MD = -13.4 ± 3.8; p = 0.04). These results suggest that practitioners working with ice hockey athletes may benefit from profiling hip strength in these unilateral joint-specific angle positions because they provide an evidence base to determine the hip strength needs of ice hockey athletes in positions associated with skating performance and noncontact hip and groin injury mechanisms (between 25° and 50° of hip abduction). [ABSTRACT FROM AUTHOR]

Reference anthropometric and physical performance qualities can improve understanding of sporting needs and streamline preparation and rehabilitation programs. However, these data and their relationships with competitive success are absent in rodeo athletes. We hypothesized that riding performance would be most correlated with hip adductor, neck, and grip strength, whereas jump, reactive strength index (RSI), and change of direction abilities would best predict bull-fighting performance. Forty-three amateur (n = 9), professional (n = 23), or internationally ranked (n = 11) male rodeo athletes (bareback = 9, bull riders = 16, saddle bronc = 7, bullfighters = 11) (26.8 ± 5.6 years) volunteered for this study. Anthropometrics included body mass, height, and body fat percentage. Performance measures included isometric hip adduction and abduction, neck flexion and extension, handgrip strength, squat and countermovement jump heights, eccentric utilization ratio, reactive strength index, change of direction, bike sprints, and several pneumatic power measures. Bullfighters were taller and heavier than bull riders (effect size [ES] = 0.84-0.87, p = 0.008-0.017). Bull riders were leaner than bullfighters (ES = 0.74, p = 0.012). Fighters had greater RSI than riders (ES = 0.73-1.47, p < 0.001-0.030). Competitive level of rodeo riders (n = 32) correlated with age, rodeo experience (ρ = 0.37-0.43, p = 0.013-0.049), bent-leg abduction (ρ = 0.43, p = 0.014), straight-leg hip adduction and abduction (ρ = 0.49-0.56, p < 0.001-0.005), neck flexion force (ρ = 0.43, p = 0.016), and rotational power (ρ = 0.50, p = 0.004). The competitive level of the fighters correlated with age (ρ = 0.64, p = 0.036) and time trial performance (ρ = -0.76, p = 0.006). This is the first study providing normative and correlational strength and power performance data in a rodeo population. These data highlight the need for more event-specific physical preparation. Riders should focus their physical preparation on hip and neck strength and rotational power. Bullfighters should prioritize stiffness and anaerobic power. [ABSTRACT FROM AUTHOR]

Previous research established that male powerlifters have less range of motion (ROM) in several movements about the shoulder and hip compared with sedentary male subjects. It is unclear if these differences in ROM are related to strength, training type, and years of training experience or if individuals with less ROM have a better propensity to gain strength. The purpose of this study was to compare strength and ROM in male powerlifters and recreationally strength-trained male subjects and to determine if ROM would be an effective predictor of strength in these groups. Twelve powerlifters and 12 recreationally strength-trained control subjects completed 1 repetition maximum (1RM) squat and bench press testing. In a subsequent session, active ROM was measured, and velocity data were collected during submaximal squat repetitions. There was no significant difference (p > 0.05) between the groups for age, height, body mass, training experience, and training frequency. Powerlifters had significantly greater (p ≤ 0.05) training duration and absolute squat and bench press 1RM. Powerlifters had significantly less shoulder extension and horizontal abduction, and hip flexion, extension, and adduction than recreationally strength-trained men. Significant negative relationships were found between 2-lift Wilks score (body mass relative strength) and shoulder extension and horizontal abduction, as well as hip flexion and extension. In powerlifters, significant negative relationships were found between competition Wilks score, shoulder extension, and hip flexion. Because these relationships correspond to the bottom position of the squat and bench press, it may be best to ensure that shoulder extension and hip flexion remain sufficient to achieve competition depth. [ABSTRACT FROM AUTHOR]

Gonçalves, BM, Mesquita, RNO, Tavares, F, Brito, J, Correia, P, Santos, P, and Mil-Homens, P. A new portable device to reliably measure maximal strength and rate of force development of hip adduction and abduction. J Strength Cond Res 36(9): 2465–2471, 2022—Groin injuries are a major issue in sports involving kicking or quick changes of direction. Decreased hip adduction and abduction strength have been indicated as one of the main risk factors for groin injury. The methods currently available to measure hip adduction and abduction strength are reliable but highly dependent on the evaluator skills. Furthermore, several studies have reported the reliability of maximal strength (MVIC), but very few studies investigated the reliability of explosive strength (RFD), a parameter that has been previously shown to have a higher functional value. The aim of the current investigation was to assess the reliability of a user-independent portable dynamometer that concurrently measures MVIC and RFD. Twenty-five healthy young subjects performed maximal isometric hip adduction and abduction in both sitting and supine positions. Measurements occurred in 2 different days separated by 48–72 hours. Test-retest reliability was calculated for both MVIC and RFD. Both MVIC and RFD showed good relative reliability (intraclass correlation coefficient = 0.77–0.98) with no differences between positions or muscle actions. Measurement error was similar between positions for MVIC in both hip adduction and abduction. Measurements of RFD showed higher reliability using a time window of at least 0–100 milliseconds, and lower measurement error was observed in sitting for adduction and in supine for abduction. This study shows that portable dynamometry can be used to concurrently measure hip adduction and abduction maximal and explosive strength, with levels of reliability that are similar to previously described methods. [ABSTRACT FROM AUTHOR]

Supplemental Digital Content is Available in the Text. Robles-Palazón, FJ, Ayala, F, Cejudo, A, De Ste Croix, M, Sainz de Baranda, P, and Santonja, F. Effects of age and maturation on lower extremity range of motion in male youth soccer players. J Strength Cond Res 36(5): 1417–1425, 2022—Restricted joint range of motion (ROM) has been considered as a primary risk factor for some sport-related injuries. Consequently, preparticipation assessment of lower extremity joints ROM could help identify youth soccer players at high risk of injury and to aid in the design of tailored age and maturational specific training interventions. The purpose of this study was to analyze and compare the influence of chronological age and maturational stage on several lower extremity ROM measures, as well as to describe the lower extremity ROM profile using a comprehensive approach in youth soccer players. A total of 286 male youth soccer players' ROM were assessed including passive hip (extension [PHE], adduction with hip flexed 90° [PHADHF90°], flexion with knee flexed [PHFKF] and extended [PHFKE], abduction with hip neutral [PHABD] and flexed 90° [PHABDHF90°], external [PHER] and internal [PHIR] rotation), knee (flexion [PKF]) and ankle (dorsiflexion with knee flexed [ADFKF] and extended [ADFKE]) ROMs. Between-group differences were analyzed using a one-way analysis of variance (ANOVA) and magnitude-based decisions. The results only report statistically significant (p < 0.05; d > 0.5) and clinically relevant differences (>8°) for the PKF ROM between U12 vs. U19, and Pre-PHV vs. Post-PHV groups. Furthermore, approximately 40, 35, and 20% of players displayed restrictions in their PHFKE, PKF, and ADFKF ROM values, respectively. These findings emphasize the necessity of prescribing (across all age groups and periods of growth and maturation) compensatory measures in daily soccer training, and these exercises should be equally applied to both limbs with the aim of improving PHFKE, PKF and ADFKF ROM values. [ABSTRACT FROM AUTHOR]

Nagao, H and Ishii, Y. Characteristics of the shrug motion and trapezius muscle activity during the power clean. J Strength Cond Res 35(12): 3288-3295, 2021-Although the shrug motion and trapezius muscle activity are commonly considered as important in Olympic weightlifting exercises, there are no data on the shrug motion in Olympic weightlifting. Providing objective data on shrug motion and upper trapezius muscle (TZ) activity during power clean (PC) will help coaches properly evaluate technique and select accessory exercises. The purpose of this study was to clarify the role of the shrug motion and TZ activity during PC. Twenty trained men performed the PC at 50, 70, and 90% of 1 repetition maximum (1RM). Kinematics motion data and TZ surface electromyography were recorded. The range of motion of the shrug angle (sROM) and scapular adduction angle (aROM) were calculated during each phase of the PC. The TZ activity of each phase was evaluated by the root-mean-square of TZ activity (TZ%RMS), normalized by the maximal voluntary contraction. In the first pull and transition phases, TZ%RMS was significantly larger (p < 0.05; [eta]2 = 0.10, 0.11) at 90% 1RM than at 50% 1RM. In the second pull phase, the sROM and aROM were significantly larger (p < 0.01; [eta]2 = 0.19, 0.19) at 50% 1RM than at 90% 1RM, and the TZ%RMS was significantly larger (p < 0.01; [eta]2 = 0.30) at 50% 1RM than at 70% 1RM and 90% 1RM, and at 70% 1RM than at 90% 1RM. Trapezius muscle activity appears to work to maintain scapular position, especially in the first pull and transition phases. In the second pull phase, the TZ was aggressively contracted to elevate the scapula and pull the barbell, but the sROM decreased as the load increased. [ABSTRACT FROM AUTHOR]

Secomb, JL, Dascombe, BJ, and Nimphius, S. Importance of joint angle-specific hip strength for skating performance in semiprofessional ice hockey athletes. J Strength Cond Res 35(9): 2599-2603, 2021--Ice hockey athletes with faster sprint acceleration and change-of-direction (COD) skating performance possess a competitive advantage. However, it is unknown whether joint anglespecific hip strength, in combination with measures known to relate to skating performance (e.g., countermovement jump [CMJ]), better explains skating performance. The purpose of this research was to determine whether hip strength in joint angles specific to skating positions and CMJ performance explains sprint skating acceleration and COD performance. Thirteen semiprofessional male hockey (26.76 6.7 years; 88.4 618.1 kg; 181.9 6 5.4 cm) athletes were assessed for CMJ performance, hip abduction and adduction strength, 10-m sprint skating acceleration, and COD (505) performance. Linear multiple regressions to predict skating acceleration and COD performance were calculated with variables chosen based on functional justification and magnitude of correlation. Hip abductor relative peak force (rPF) at 25° of hip abduction and CMJ rPF explained 46.0% (adjusted) of variance in sprint acceleration performance (F[2,12] 5 6.18, p 5 0.02). Countermovement jump peak eccentric velocity, adductor rPF at 50° of hip abduction, and difference in abductor rPF between 50° and 25° of hip abduction explained 85.0% (adjusted) of the variance in 505 time (F[3,12] 5 22.8, p, 0.001). Hip strength at joint angles functionally relevant to skating (e.g., at 25° and 50°), in combination with relevant CMJ variables, explained large and very large amounts of variance in sprint skating acceleration andCODperformance in this cohort. The inclusion of joint angle-specific hip strength profiling to a physical performance testing battery may provide practitioners with more specific knowledge on the strength of the hip through abduction range of motion, which may affect skating performance. [ABSTRACT FROM AUTHOR]

This study investigated the effect of hip joint position on the activity level of individual hamstring muscles during stiff-leg deadlift. Fourteen male collegiate sprinters performed stiff-leg deadlift in the adducted (ADD), neutral (NT), abducted (ABD), internally rotated by 20° (IN20), and externally rotated positions by 20° (EX20) and by 40° (EX40) of the hip joint. Surface electromyogram (EMG) was recorded from the proximal and distal regions of the biceps femoris long head (BFlh), semitendinosus (ST), and semimembranosus (SM). Root mean square value of EMG (RMS-EMG) data were calculated for the concentric and eccentric phases of deadlift and was normalized by RMS-EMG during maximal voluntary contraction of isometric knee flexion as an activity level. Results revealed that the activity level of BFlh during the concentric phase was higher in EX20 (p50.008, difference56.3%) and EX40 (p50.001, difference59.4%) than in NT. Semimembranosus showed a higher activity level in IN20 than in EX40 during the concentric (p 5 0.004, difference 5 4.3%) and eccentric phases (p 5 0.023, difference 5 4.1%). In addition, the activity level was higher in ABD than in NT for BFlh (p 50.015, difference 5 4.6%), ST (p 5 0.047, difference 5 3.8%), and SM (p 5 0.005, difference 5 3.9%) during the concentric phase of deadlift. In conclusion, the deadlift in the hip-abducted position requires high activation of the individual hamstrings and that in the hip externally and internally rotated positions needs high activation of BFlh and SM, respectively. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare isometric and isokinetic hip, knee, and ankle strength in children with overweight/obesity (OWB) and typical weight (TW) of age 6-12 years. Absolute torque and torque allometrically scaled to body mass and fat-free mass were derived to allow for comparison of strength irrespective of body size. Using a cross-sectional design, 26 OWB (body mass index [BMI] Z score: 2.28 ± 0.77, 54% females) children were matched in age and height with 26 TW (BMI Z score: -0.39 ± 0.96, 54% females). Subjects performed maximal isometric and isokinetic contractions in ankle dorsiflexion and plantarflexion, knee flexion and extension, hip flexion and extension, and isometric hip abduction and adduction. Between-group differences in absolute and normalized isometric and isokinetic strength were compared with 1-way analysis of variances. Statistical significance was set at p < 0.05. Children with OWB had significantly greater absolute torque in the knee flexors and extensors (15-21%) and greater isokinetic ankle dorsiflexion (8%) but lower isometric hip abduction (21%) compared with TW children. When strength was allometrically scaled to body mass, children with OWB were significantly weaker at the ankle (19-25%), hip (21-36%), and in the knee extensors (12-15%). When torque was allometrically scaled to fat-free mass, children in the OWB group had greater knee flexor and extensor strength (12-14%) but were weaker in isometric hip abduction (33%) and isokinetic hip flexion and extension (29-40%). The results demonstrated that deficits in strength, relative to body mass, at the ankle and hip may be greater than those of the knee. These strength deficits in the group with OWB highlight the need for targeted musculoskeletal strength interventions to incorporate all lower-limb muscle groups. [ABSTRACT FROM AUTHOR]

The adductor squeeze strength test has become a popular training monitoring marker, particularly in team sports. The aim of this study was to investigate the relationship between adductor squeeze strength scores, subjective markers of recovery and training load in elite Rugby Union players, because of limited research in this area. Nineteen elite male Rugby Union players completed daily monitoring markers (adductor squeeze strength and 5 selected subjective markers of recovery), over a 10-week preseason training period. Rate of perceived exertion (RPE) was collected to determine training load (session RPE; RPE × session duration) and to calculate weekly training load. Spearman's correlation was used to analyze the relationship between adductor squeeze strength scores, subjective markers of recovery, and weekly training load. The results found that where adductor squeeze scores decreased, both perceived fatigue levels ( r = -0.335; R2 = 11.2%; p < 0.001) and muscle soreness ( r = -0.277; R 2 = 7.7%; p < 0.001) increased. A weak correlation was found between Monday adductor squeeze strength scores and the previous week's training load ( r = -0.235; R 2 = 5.5%; p < 0.001) and Friday adductor squeeze strength scores and the same week's training load ( r = -0.211; R2 = 4.5%; p < 0.05). These results show that adductor squeeze strength may provide coaches with a time-efficient, low-cost objective, player monitoring marker. Additionally, the combination of adductor strength squeeze, with subjective markers, perceived fatigue, and muscle soreness, and appropriately planned training load may help coaches to optimize training adaptations by determining a player's training status. [ABSTRACT FROM AUTHOR]

A warm-up is an important period before training or competition to prepare an athlete for the physical demands of subsequent activity. Previous research has extensively focused on the effects of warm-up in relation to various jumping performance attributes; however, limited research has examined the biomechanical nature of landings after common warm-up practices. Twelve female, collegiate-level volleyball players performed unilateral landings on the dominant and nondominant limb before and after dynamic warm-ups and combined dynamic-static (CDS) warm-ups. Kinetic variables of interest were measured at the hip and knee during the landing phase of a volleyball-simulated jump-landing maneuver. A significant 3-way interaction (warm-up x limb x time) for peak internal knee adduction moment was observed, as this kinetic parameter significantly increased (p = 0.01; d = 0.79) in the nondominant limb at 1-minute post-CDS warm-up. No other warm-up differences were detected; however, significant main effects of limb were determined for dominant-limb internal hip abduction moment (p < 0.01; d = 1.32), dominant-knee internal rotation moment (p < 0.01; d = 1.88), and nondominant-knee external rotation moment (p < 0.01; d = 1.86), which may be due to altered hip and trunk mechanics during the jump landings. This information provides strength and conditioning professionals with biomechanical information to determine warm-up protocols that reduce the risk of injury in female volleyball athletes. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the effects of game exposure on pitchers and catchers' hip and glenohumeral range of motion (ROM), isometric strength, and vertical jump performance and power. Five college female softball pitchers (174.24 ± 7.53 cm; 82.10 ± 11.27 kg; 20 ± 1.82 years) and 4 catchers (165.10 ± 9.04 kg; 68.61 ± 3.87 cm; 20 ± 1.41 years) participated. Hip and glenohumeral rotational ROM; hip and glenohum¬eral rotational isometric strength; hip abduction and adduction strength; and vertical jump height were assessed pre- and postgame exposure. The catchers displayed significantly greater throwing side hip internal rotation (IR) ROM (mean difference = +6.88°, p = 0.03) postgame exposure, whereas the pitchers exhibited less IR (mean difference = -2.02%, p = 0.013) and external rotation (ER; mean difference = -1.95%, p = 0.026) strength in the nonthrowing side hip pre vs. postgame exposure. The performance demands of pitchers and catchers vary greatly, causing position-specific decreases/increases in various tests following game performance. Pitchers exhibited significant decreases in nonthrowing side hip IR and ER strength. In catchers, throwing side hip IR ROM significantly increased following game exposure. Further evaluation of ROM, strength, and power is necessary as it is unknown how these changes following a game affect sports performance or risk of injury. [ABSTRACT FROM AUTHOR]

Martinez, AF, Lessi, GC, Carvalho, C, and Serrao, FV. Association of hip and trunk strength with three-dimensional trunk, hip, and knee kinematics during a single-leg drop vertical jump. J Strength Cond Res 32(7): 1902–1908, 2018—Kinematic changes have been correlated with different lower-limb injuries. Movement is influenced by multiple factors and strength is one of the contributors that can influence it. Thus, the aim of this study was to evaluate the correlation among trunk and hip isometric strength with trunk and lower-limb kinematics during a single-leg drop vertical jump. Twenty-three healthy recreational female athletes aged between 18 and 35 years underwent isometric evaluation of hip abductor, hip extensor, and lateral trunk muscle strength and 3-dimensional trunk and lower-limb kinematics during a single-leg drop vertical jump. Pearson's correlation coefficients (r) were calculated to establish the association among hip and trunk strength and trunk, hip, and knee kinematics. As result, no significant correlations were found between the peak and movement excursion values of kinematic and hip and trunk isometric strength data. The lack of correlation between isometric strength and kinematics in healthy female athletes indicates that intervention programs should not be focused solely on strength exercises to influence the movement pattern during single-landing activities. [ABSTRACT FROM AUTHOR]

Current measures of core stability used by clinicians and researchers suffer from several shortcomings. Three functional movement screens appear, at face-value, to be dependent on the ability to activate and control core musculature. These 3 screens may present a viable alternative to current measures of core stability. Thirty-nine subjects completed a deep squat, trunk stability push-up, and rotary stability screen. Scores on the 3 screens were summed to calculate a composite score (COMP). During the screens, muscle activity was collected to determine the length of time that the bilateral erector spinae, rectus abdominis, external oblique, and gluteus medius muscles were active. Strength was assessed for core muscles (trunk flexion and extension, trunk rotation, and hip abduction and adduction) and accessory muscles (knee flexion and extension and pectoralis major). Two ordinal logistic regression equations were calculated with COMP as the outcome variable, and: (a) core strength and accessory strength, (b) only core strength. The first model was significant in predicting COMP (p = 0.004) (Pearson's Chi-Square = 149.132, p = 0.435; Nagelkerke's R-Squared = 0.369). The second model was significant in predicting COMP (p = 0.001) (Pearson's Chi-Square = 148.837, p = 0.488; Nagelkerke's R-Squared = 0.362). The core muscles were found to be active for most screens, with percentages of "time active" for each muscle ranging from 54-86%. In conclusion, performance on the 3 screens is predicted by core strength, even when accounting for "accessory" strength variables. Furthermore, it seems the screens elicit wide-ranging activation of core muscles. Although more investigation is needed, these screens, collectively, seem to be a good assessment of core strength. [ABSTRACT FROM AUTHOR]

Anterior cruciate ligament (ACL) injury prevention programs are less successful in basketball than soccer and may be due to distinct movement strategies that these athletes develop from sport-specific training. The purpose of this study was to identify biomechanical differences between female basketball and soccer players during multidirectional jump landings. Lower extremity biomechanics of 89 female athletes who played competitive basketball (n = 40) or soccer (n = 49) at the middle- or high-school level were analyzed with 3-dimensional motion analysis during a drop vertical jump, double- (SAG-DL) and single-leg forward jump (SAG-SL), and double- (FRONT-DL) and single-leg (FRONT-SL) lateral jump. Basketball players landed with either less hip or knee, or both hip and knee excursion during all tasks (p ≤ 0.05) except for the SAGSL task, basketball players landed with greater peak hip flexion angles (p = 0.04). The FRONT-SL task elicited the most distinct sport-specific differences, including decreased hip adduction (p < 0.001) angles, increased hip internal rotation (p = 0.003), and increased relative knee external rotation (p = 0.001) excursions in basketball players. In addition, the FRONT-SL task elicited greater forces in knee abduction (p = 0.003) and lesser forces in hip adduction (p = 0.001) and knee external rotation (p < 0.001) in basketball players. Joint energetics were different during the FRONT-DL task, as basketball players exhibited less sagittal plane energy absorption at the hip (p < 0.001) and greater hip (p < 0.001) and knee (p = 0.001) joint stiffness. Sport-specific movement strategies were identified during all jump landing tasks, such that soccer players exhibited a more protective landing strategy than basketball players, justifying future efforts toward sport-specific ACL injury prevention programs. [ABSTRACT FROM AUTHOR]

This study determined the magnitude of change in adductor strength after a competitive match in academy rugby union players and examined the relationship between locomotive demands of match-play and changes in postmatch adductor strength. A within-subject repeated measures design was used. Fourteen academy rugby union players (age, 1 7.4±0.8 years; height, 1 82.7±7.6 cm; body mass, 86.2±11.6 kg) participated in the study. Each player performed 3 maximal adductor squeezes at 45² of hip flexion before and immediately, 24, 48, and 72 hours postmatch. Global positioning system was used to assess locomotive demands of match-play. Trivial decreases in adductor squeeze scores occurred immediately (21.3±2.5%; effect size [ES] = 20.11±0.21; likely, 74%) and 24 hours after match (20.7±3%; ES = 20.06±0.25; likely, 78%), whereas a small but substantial increase occurred at 48 hours (3.8±1.9%; ES = 0.32±0.16; likely, 89%) before reducing to trivial at 72 hours after match (3.1±2.2%; ES = 0.26±0.18; possibly, 72%). Large individual variation in adductor strength was observed at all time points. The relationship between changes in adductor strength and distance covered at sprinting speed (...O2max ≥ 81%) was large immediately postmatch (p = 0.056, r = 20.521), moderate at 24 hours (p = 0.094, r = -- 0.465), and very large at 48 hours postmatch (p = 0.005, r = 20.707). Players who cover greater distances sprinting may suffer greater adductor fatigue in the first 48 hours after competition. The assessment of adductor strength using the adductor squeeze test should be considered postmatch to identify players who may require additional rest before returning to field-based training. [ABSTRACT FROM AUTHOR]

The article discusses the study on the importance of the four muscle groups involving elbow flexors (RF), digit flexors (DF), shoulder adductors (SA), and lumbar flexors (LF) in rock climbing performance. The method for the measurement of the muscle ability through prefatiguing exercise considering maximum voluntary isometric contraction (MVIC) was designed. The results were outlined and concludes that climbing performance was significantly affected after the prefatigue of DF followed by EF.

The article reports on research which was conducted to investigate the kinematics and kinematics of two types of military athletic footwear; the PT-03 cross-trainer and PT 1000 running shoe. They found that the PT-3 was linked to kinetic and kinematic factors associated with injuries and concluded that the PT 1000 should be used for running exercises.

The article discusses research which was conducted to investigate and compare the relationship between several measures of single-joint, isometric, eccentric, and squat strength and unilateral and bilateral landing mechanics at the hip and knee in women. Researchers evaluated 26 healthy and athletic female subjects. They found that squat strength was related to hip adduction, that isometric and eccentric measures demonstrated few correlations with hip and knee excursion and that hip and knee flexion and rotation were not related to strength.

The article discusses a study which was aimed to compare lower extremity (LE) muscle activation and passive range of motion (PROM) between subjects who display visual medial knee displacement (MKD) during a single leg squat (SLS) and those who do not. The study included 40 physically active adults. The study findings indicate that MKD during a SLS seems to be influenced by decreased coactivation of the gluteal to the hip adductor muscles and restricted dorsiflexion.

The article discusses research investigating effects of resistance training fatigue on joint biomechanics. The authors argue that resistance training performed with short rest can result in substantial fatigue that can have a negative impact on exercise technique. The results of an examination of what residual movement effects may exist after a resistance training workout in 12 men with six months of resistance training experience as a result of fatigue are discussed.

The article discusses research investigating the internal joint moments of the lower limb during vertical jumping and the weightlifting jerk. According to the authors, the purpose of the study is to improve awareness of the control strategies and correspondence between these activities and facilitate an understanding of the transfer of training effects. Topics include the study's experimental design, the collection and analysis of kinematic data, and a discussion of the results.

The article reports on research which was conducted to examine abdominal and back muscle activity in women during dynamic upper limb exercises while standing and to evaluate whether the exercises were appropriate for strengthening muscles. Researchers evaluated 20 women. They found that shoulder extension and shoulder abduction and adduction with the pelvis fixed elicited the greatest muscle activity and that exercises performed in the standing position are effective for activating muscles.

The article reports on research conducted to investigate the effects a 10-week off-season neuromuscular training program had on lower extremity kinematics and to determine whether it could be used to reduce the risk of anterior cruciate ligament (ACL) injuries in soccer players. Researchers evaluated 12 division one female soccer players. They found that the training program altered frontal plane kinematics in the players and that it may reduce the risk of incurring an ACL injury.

The article presents a study on the effects of four voluntary breathing conditions on maximal voluntary isometric force of large muscle groups. It states that 10 subjects conducted maximum voluntary isometric contractions (MVICs) of knee flexion and extension, shoulder abduction and adduction, and elbow flexion and extension under all breathing conditions, including normal breathing, forced inhalation, forced exhalation, and the Vasalva manuever (VM).