Biomechanical Differences Between the Bulgarian Split-Squat and Back Squat

International Journal of Exercise Science 14(1): 533-543, 2021. The Bulgarian split squat (BSS) is a unilateral lower extremity strength exercise; however, the mechanical demands have not been fully elucidated. The purpose of this study was to compare ankle, knee, and hip joint net joint moment impulse (NJMI), work (NJW), peak net joint moment (NJM) and peak displacement between the BSS and traditional bilateral back squat (BS). Following a practice and 1-repetition maximum (1-RM) session, 2x3 BS (70% 1-RM) and BSS (35% 1-RM) were completed by twenty resistance trained males (24.20 ± 2.50 yrs, 1.76 ± 0.06m, 85.3 ± 13.90 kg). Significant squat type x joint interactions were revealed for NJMI (p \u3c 0.001), NJW (p \u3c 0.001), peak NJM (p \u3c 0.001), and peak displacement (p = 0.011). For both squats, hip NJMI, NJW, and peak NJM was significantly greater than both ankle (d = 5.50-9.40) and knee (d = 7.50-8.50). While knee NJMI (d = 2.80) and peak NJM (d = 2.10) during the BSS was statistically less compared to ankle, during BS knee NJMI was statistically greater than ankle (d = 3.00). Ankle and knee NJW were statistically similar during BSS (d = 0.30), whereas knee NJW was statistically greater than ankle during BS (d = 3.20). Comparing between squat types within each joint demonstrated statistically equal peak displacement for the ankle (d = 0.14) and hip (d = 0.11), whereas knee joint peak displacement was significantly less for the BSS compared to BS (d = 0.82). Both the BSS and BS are hip dominant exercises. The BSS may best be used in circumstances to focus on hip extension while minimizing the knee joint demands, such as the early phases of knee rehabilitation or when addressing isolated hip extension deficiencies

Association Between the Seated Single-Arm Shot-Put Test With Isokinetic Pushing Force

Context: Previous investigations have examined the reliability, normalization, and underlying projection mechanics of the seated single-arm shot-put (SSASP) test. Although the test is believed to reflect test limb strength, there have been no assessments determining whether test performance is directly associated with upper-extremity strength. Objective: To determine the relationship between isokinetic pushing force and SSASP performance and conduct a method comparison analysis of limb symmetry indices between the 2 tests. Design: Controlled laboratory study. Setting: Biomechanics laboratory. Patients (or Other Participants): Twenty-four healthy and physically active men (n = 12) and women (n = 12). Intervention(s): Participants completed the SSASP and isokinetic pushing tests using their dominant and nondominant arms.Main OutcomeMeasures: SSASP distance and isokinetic peak force. Results: Significant moderate to strong relationships were revealed between the SSASP distances and isokinetic peak forces for both limbs. The Bland–Altman analysis results demonstrated significantly (P \u3c .002) greater limb symmetry indices for the SSASP (both medicine balls) than the isokinetic ratios, with biases ranging from −0.094 to −0.159. The limits of agreement results yielded intervals ranging from ±0.241 to ±0.340 and ±0.202 to ±0.221 from the biases. Conclusions: These results support the notion that the SSASP test reflects upper-extremity strength. The incongruency of the limb symmetry indices between the 2 tests is likely reflective of the differences in the movement patterns and coordination requirements of the 2 tests

Analysis of Heel Raise Exercise with Three Foot Positions

ABSTRACT Prior research revealed activation differences between the medial (MG) and lateral (LG) gastrocnemius when performing heel raise exercise with neutral (N), internally-rotated (IR) and externally-rotated (ER) foot positions. Studying underlying biomechanics may help explain activation differences. The purpose was to compare ankle (AN), knee (KN), and hip (HI) contributions (initial joint angles) to attaining each initial foot position, ankle flexion-extension range of motion, ankle mechanical energy expenditure, repetition time, and percent cycle concentric-eccentric transition between N, IR, and ER foot positions. Twenty healthy subjects (11 male, 9 female) with resistance training experience performed twelve repetitions of free-weight (135% body mass) heel raise exercise using N, IR and ER foot positions in a counterbalanced order. Forefeet were elevated .05m onto separate forceplates. Electromagnetic sensors secured along dominant lower limb recorded kinematic data. Dependent variables were averaged across five selected repetitions. No significant differences existed for repetition time (P=.209), percent cycle concentric-eccentric transition (P=.668), ankle mechanical energy expenditure (P=.590), and ankle flexion-extension range of motion (P=.129) between foot positions. Post hoc comparison of a significant joint by foot position interaction (P\u3c.001) demonstrated IR\u3eN\u3eER for the initial HI and KN angles, whereas for AN, ER\u3eIR and N. Between joints: ANA

Analysis of Heel Raise Exercise with Three Foot Positions

Prior research revealed activation differences between the medial (MG) and lateral (LG) gastrocnemius when performing heel raise exercise with neutral (N), internally-rotated (IR) and externally-rotated (ER) foot positions. Studying underlying biomechanics may help explain activation differences. The purpose was to compare ankle (AN), knee (KN), and hip (HI) contributions (initial joint angles) to attaining each initial foot position, ankle flexion-extension range of motion, ankle mechanical energy expenditure, repetition time, and percent cycle concentric-eccentric transition between N, IR, and ER foot positions. Twenty healthy subjects (11 male, 9 female) with resistance training experience performed twelve repetitions of free-weight (135% body mass) heel raise exercise using N, IR and ER foot positions in a counterbalanced order. Forefeet were elevated .05m onto separate forceplates. Electromagnetic sensors secured along dominant lower limb recorded kinematic data. Dependent variables were averaged across five selected repetitions. No significant differences existed for repetition time (P=.209), percent cycle concentric-eccentric transition (P=.668), ankle mechanical energy expenditure (P=.590), and ankle flexion-extension range of motion (P=.129) between foot positions. Post hoc comparison of a significant joint by foot position interaction (P\u3c.001) demonstrated IR\u3eN\u3eER for the initial HI and KN angles, whereas for AN, ER\u3eIR and N. Between joints: ANA

Reliability of Upper Extremity Functional Performance Tests for the Non-overhead Athlete

# Background While there have been reliability studies conducted on several upper extremity functional performance tests (UEFPT), there are several complicating factors that inhibit the ability to draw definitive consensus about the reliability of the tests in both females and males. Having reliability estimates for UEFPT in the same cohort facilitates direct comparison of their relative and absolute reliability. # Purpose To establish the test-retest reliability of the closed kinetic chain upper extremity stability test (CKCUEST), seated medicine ball chest pass test (SMBCPT) and hands-release push-up test (HRPUT) in a cohort of males and females with a history of non-overhead sport participation. A secondary purpose was to examine the associations between the three UEFPT. # Study Design Test-retest reliability, single cohort study. # Methods Forty adults (20 females, 20 males) with a history of non-overhead sport participation completed three UEFPT during two data collection sessions three to seven days apart. Measures of systematic bias, absolute reliability and relative reliability were computed between the sessions. Additionally, correlational analyses were conducted between the three UEFPT. # Results Only the UECKCST (both sexes) demonstrated significant (p≤ 0.003) second session performance improvements. All three tests exhibited excellent relative reliability (intraclass correlational coefficients ≥ 0.823) and except for the HRPUT in males, coefficients of variation were all below 8.8%. Except for a significant relationship (r=.691, p=0.001) between the UECKCST and SMBCPT for the females there were no other associations between the three UEFPT. # Conclusion All three UEFPT demonstrated sufficient reliability. Thus, all three assessments can be used for serial assessments to progress a patient through rehabilitation as well as contribute to the criteria used in making return to sport decisions. # Level of Evidence

Heart Rate Variability, Neuromuscular and Perceptual Recovery Following Resistance Training

We quantified associations between changes in heart rate variability (HRV), neuromuscular and perceptual recovery following intense resistance training (RT). Adult males (n = 10) with \u3e1 year RT experience performed six sets to failure with 90% of 10 repetition maximum in the squat, bench press, and pull-down. Changes (∆) from pre- to immediately (IP), 24 and 48 h post-RT were calculated for neuromuscular performance markers (counter-movement jump peak power and mean concentric bench press and squat velocity with load corresponding to 1.0 m∙s−1) and perceived recovery and soreness scales. Post-waking natural logarithm of the root-mean square of successive differences (LnRMSSD) in supine and standing positions were recorded pre-RT (5 day baseline), IP and two mornings post-RT. All parameters worsened at IP (p \u3c 0.05). LnRMSSD measures were not different from baseline by 24 h. Neuromuscular markers were not different from pre-RT by 48 h. Perceptual measures remained suppressed at 48 h. No significant associations among ∆ variables were observed (p = 0.052–0.978). These data show varying timeframes of recovery for HRV, neuromuscular and perceptual markers at the group and individual level. Thus, post-RT recovery testing should be specific and the status of one metric should not be used to infer that of another

Kinematic Analysis of Four Plyometric Push-Up Variations

International Journal of Exercise Science 5(4) : 334-343, 2012. Plyometric research in the upper extremity is limited, with the effects of open-chain plyometric exercises being studied most. Kinematic and ground reaction force data concerning closed-chain upper extremity plyometrics has yet to be examined. Twenty-one recreationally active male subjects performed four variations of plyometric push-ups in a counterbalanced order. These included box drop push-ups from 3.8 cm, 7.6 cm, 11.4 cm heights, and clap push-ups. Kinematics of the trunk, dominant extremity and both hands were collected to examine peak flight, elbow flexion at ground contact, elbow displacement, and hand separation. Additionally peak vertical ground reaction force was measured under the dominant extremity. The 11.4 cm and clap push-ups had significantly higher peak flight than the other variations (P\u3c.001). At ground contact, the elbow was in significantly greater flexion for the 3.8 cm and clap push-up compared to the other variations (P\u3c.001). The clap push-up had significantly more elbow displacement than the other variations (P\u3c.001) while hand separation was not significantly different between variations (P=.129). Peak vertical ground reaction force was significantly greater for the clap push-ups than for all other variations (P\u3c .001). Despite similar flight heights between the 11.4 cm and clap push-ups, the greater peak vertical ground reaction force and elbow displacement of the clap push-ups indicates the clap push-up is the most intense of the variations examined. Understanding the kinematic variables involved will aid in the creation of a closed chain upper-extremity plyometric progression

All in the Balance: Testing and Training Balance following Musculoskeletal Injury

Presentation given at 2018 Georgia Athletic Trainers Association Annual Meeting

Evidence and Methods for Upper Extremity Strength Testing

Presentation given at American Physical Therapy Association Combined Sections Meeting