Bench Press Range-of-Motion and Velocity-based Repetition Control: Effects on Ballistic Push-up Performance in Males.

The purpose of this study was to investigate whether the ballistic push-up (BPU) is responsive to post-activation performance enhancement (PAPE) after a bench press conditioning exercise using velocity-based repetition control. Additionally, we aimed to evaluate the effects of range of motion (ROM) conditions on subsequent BPU performance. In a randomized crossover design, 18 males performed two conditions (full ROM and self-selected partial ROM) of bench press at 80% of their 1RM until mean concentric velocity dropped 10%. Each participant performed two pre- and six post-test BPUs to assess the PAPE effect. Paired sample t-tests assessed bench press performance measures. Multiple two-way repeated measures ANOVAs assessed differences in flight time, impulse, and peak power for the pre- and post-test BPUs. No significant differences existed between ROM conditions for total repetitions, volume load, or peak velocity. Compared to partial ROM, full ROM showed greater displacement (0.42 ± 0.05 vs. 0.34 ± 0.05 m), work (331.99 ± 67.72 vs. 270.92 ± 61.42 J), and mean velocity (0.46 ± 0.09 vs. 0.44 ± 0.08 m/s). Neither bench press ROM condition enhanced the BPU and were detrimental in some cases. Several time points showed partial ROM (flight time: 2 min post, impulse: 12 min post, peak power: 12 min post) significantly greater than full ROM, possibly indicating less fatigue accumulation. The BPU may require a different stimulus or may not be practical for PAPE effects in college-aged males. Partial ROM can be an alternative that achieves similar peak velocities while requiring less overall work.

Differences in Muscle Activity and Kinetics Between the Goblet Squat and Landmine Squat in Men and Women.

ABSTRACT: Collins, KS, Klawitter, LA, Waldera, RW, Mahoney, SJ, and Christensen, BK. Differences in muscle activity and kinetics between the goblet squat and landmine squat in men and women. J Strength Cond Res 35(10): 2661-2668, 2021-Squat exercise variations are widely used and extensively researched. However, little information exists on the goblet squat (GBS) and landmine squat (LMS) and differences between men and women. This study investigated the differences in muscle activity and kinetics between the GBS and the LMS in 16 men and 16 women. Five repetitions of each squat type were performed loaded at 30% of their body mass. Vertical and anteroposterior ground reaction forces for the eccentric and concentric phases and peak vertical force were recorded with a force plate. Electromyographic (EMG) signals were recorded for the vastus medialis (VM), vastus lateralis (VL), semitendinosus (ST), and biceps femoris (BF). Normalized mean EMG values and ground reaction forces were analyzed with repeated measures analysis of variance (p < 0.05). Significant main effects for squat condition and sex were found. The LMS reduced activity in the quadriceps (VM and VL) muscles and vertical forces, while increasing posterior horizontal forces. In the LMS, men showed decreased ST activity, whereas women had decreased BF activity. Women exhibited greater quadriceps activity in both the GBS and LMS and greater ST in the LMS. Women also produced greater eccentric vertical force in both the GBS and LMS and less posterior horizontal forces in the LMS. The LMS may be useful to balance hamstring to quadriceps activity, increase horizontal loading, and reduce vertical loading. Conversely, the GBS can better target quadriceps activity and increase vertical loading. Sex differences should be considered for training programs that include the GBS and LMS.

Handgrip Strength Asymmetry and Weakness are Differentially Associated with Functional Limitations in Older Americans.

Background: Handgrip strength (HGS) is a convent measure of strength capacity and associated with several age-related health conditions such as functional disability. Asymmetric strength between limbs has been linked to diminished function. Therefore, both HGS asymmetry and weakness could be associated with functional disability. We examined the associations of HGS asymmetry and weakness on functional limitations in a nationally representative sample of older Americans. Methods: Data were analyzed from 2689 adults ≥ 60 years who participated in the 2011-2012 and 2013-2014 waves of the National Health and Nutrition Examination Survey. Weakness was defined as HGS < 26 kg for men and < 16 kg for women. Asymmetry was determined from the ratio of the dominant and non-dominant HGS. Those with HGS ratio 0.9-1.1 were considered as having HGS symmetry, and those outside this range had asymmetry. Results: Compared to those with symmetric HGS and were not weak, those with weakness alone, and both weakness and HGS asymmetry had 2.47 (95% confidence interval [CI]: 1.14-5.35) and 3.93 (CI: 1.18-13.07) greater odds for functional limitations, respectively. However, HGS asymmetry alone was not associated with functional limitations (odds ratio: 0.80; CI: 0.62-1.03). Conclusion: The use of HGS asymmetry in protocols could improve the prognostic value of handgrip dynamometers.