Submaximal Elastic Resistance Band Tests to Estimate Upper and Lower Extremity Maximal Muscle Strength

Muscle strength assessment is fundamental to track the progress of performance and prescribe correct exercise intensity. In field settings, simple tests are preferred. This study develops equations to estimate maximal muscle strength in upper- and lower-extremity muscles based on submaximal elastic resistance tests. Healthy adults (n = 26) performed a maximal test (1 RM) to validate the ability of the subsequent submaximal tests to determine maximal muscle strength, with elastic bands. Using a within-group repeated measures design, three submaximal tests of 40%, 60%, and 80% during (1) shoulder abduction, (2) shoulder external rotation, (3) hip adduction, and (4) prone knee flexion were performed. The association between number of repetitions and relative intensity was modeled with both 1st and 2nd order polynomials to determine the best predictive validity. For both upper-extremity tests, a strong linear association between repetitions and relative intensity was found (R² = 0.97–1.00). By contrast, for the lower-extremity tests, the associations were fitted better with a 2nd order polynomial (R² = 1.00). The results from the present study provide formulas for predicting maximal muscles strength based on submaximal resistance in four different muscles groups and show a muscle-group-specific association between repetitions and intensity.

Minimal Clinically Important Difference for Quadriceps Muscle Strength in People with COPD following Pulmonary Rehabilitation

Quadriceps strength training is a key component of pulmonary rehabilitation (PR). Clinical interpretability of changes in muscle strength following PR is however limited due to the lack of cut-off values to define clinical improvement. This study estimated the minimal clinically important difference (MCID) for the isotonic and isometric quadriceps muscle strength assessed with the one-repetition maximum (1RM) and hand-held dynamometry (HHD) in people with chronic obstructive pulmonary disease (COPD) following PR.A secondary analysis of a real life non-randomised controlled study was conducted in people with COPD enrolled in a 12-week community-based PR programme. Anchor and distribution-based methods were used to compute the MCIDs. The anchors explored were the St. George's respiratory questionnaire (SGRQ) and the six-minute walk test (6MWT) using Pearson's correlations. Pooled MCIDs were computed using the arithmetic weighted mean (2/3 anchor, 1/3 distribution-based methods) and reported as absolute and/or percentage of change values.Eighty-nine people with COPD (84% male, 69.9 ± 7.9 years, FEV₁ 49.9 ± 18.9% predicted) were included. No correlations were found between changes in 1RM and the SGRQ neither between changes in HHD and the SGRQ and 6MWT (p > 0.05). Thus, anchor-based methods were used only in the MCID of the 1RM with the 6MWT as the anchor. The pooled MCIDs were 5.7Kg and 26.9% of change for the isotonic quadriceps muscle strength with 1RM and 5.2KgF for isometric quadriceps muscle strength assessed with HHD.The MCIDs found are estimates to improve interpretability of community-based PR effects on quadriceps muscle strength and may contribute to guide interventions.

Effect of Resistance-Training Programs Differing in Set Configuration on Maximal Strength and Explosive-Action Performance

PURPOSE

To compare the effects of 2 upper-body strength-training programs differing in set configuration on bench press 1-repetition maximum (BP1RM), bench press throw peak velocity against 30 kg (BPT30), and handball throwing velocity.

METHODS

Thirty-five men were randomly assigned to a traditional group (TRG; n = 12), rest redistribution group (RRG; n = 13), or control group (n = 10). The training program was conducted with the bench press exercise and lasted 6 weeks (2 sessions per week): TRG-6 sets × 5 repetitions with 3 minutes of interset rest; RRG-1 set × 30 repetitions with 31 seconds of interrepetition rest. The total rest period (15 min) and load intensity (75% 1RM) were the same for both experimental groups. Subjects performed all repetitions at maximal intended velocity, and the load was adjusted on a daily basis from velocity recordings.

RESULTS

A significant time × group interaction was observed for both BP1RM and BPT30 (P < .01) due to the higher values observed at posttest compared with pretest for TRG (effect size [ES] = 0.77) and RRG (ES = 0.56-0.59) but not for the control group (ES ≤ 0.08). The changes in BP1RM and BPT30 did not differ between TRG and RRG (ES = 0.04 and 0.05, respectively). No significant differences in handball throwing velocity were observed between the pretest and posttest (ES = 0.16, 0.22, and 0.02 for TRG, RRG, and control group, respectively).

CONCLUSIONS

Resistance-training programs based on not-to-failure traditional and rest redistribution set configurations induce similar changes in BP1RM, BPT30, and handball throwing velocity.

Influence of Grip Width and Anthropometric Characteristics on the Bench-Press Load-Velocity Relationship

PURPOSE

To compare the load-velocity (L-V) relationship between bench-press exercises performed using 4 different grip widths, to determine the association between the anthropometric characteristics and L-V profile, and to explore whether a multiple linear-regression model with movement velocity and subjects' anthropometric characteristics as predictor variables could increase the goodness of fit of the individualized L-V relationship.

METHODS

The individual L-V relationship of 20 men was evaluated by means of an incremental loading test during the bench-press exercise performed on a Smith machine using narrow, medium, wide, and self-selected grip widths. Simple and multiple linear-regression models were performed.

RESULTS

The mean velocity associated with each relative load did not differ among the 4 grip widths (P ≥ .130). Only body height and total arm length were correlated with the mean velocity associated with light and medium loads (r ≥ .464). A slightly higher variance of the velocity attained at each relative load was explained when some anthropometric characteristics were used as predictor variables along with the movement velocity (r2 = .969 [.965-.973]) in comparison with the movement velocity alone (r2 = .966 [.955-.968]). However, the amount of variance explained by the individual L-V relationships was always higher than with the multiple linear-regression models (r2 = .995 [.985-1.000]).

CONCLUSIONS

These results indicate that the individual determination of the L-V relationship using a self-selected grip width could be recommended to monitor relative loads in the Smith machine bench-press exercise.

Is the Optimal Load for Maximal Power Output During Hang Power Cleans Submaximal?

PURPOSE

The optimal load for maximal power output during hang power cleans (HPCs) from a mechanical perspective is the 1-repetition-maximum (1RM) load; however, previous research has reported otherwise. The present study thus aimed to investigate the underlying factors that determine optimal load during HPCs.

METHODS

Eight competitive Olympic weight lifters performed HPCs at 40%, 60%, 70%, 80%, 90%, 95%, and 100% of their 1RM while the ground-reaction force and bar/body kinematics were simultaneously recorded. The success criterion during HPC was set above parallel squat at the receiving position.

RESULTS

Both peak power and relative peak power were maximized at 80% 1RM (3975.7 [439.1] W, 50.4 [6.6] W/kg, respectively). Peak force, force at peak power, and relative values tended to increase with heavier loads (P < .001), while peak system velocity and system velocity at peak power decreased significantly above 80% 1RM (P = .005 and .011, respectively). There were also significant decreases in peak bar velocity (P < .001) and bar displacement (P < .001) toward heavier loads. There was a strong positive correlation between peak bar velocity and bar displacement in 7 of 8 subjects (r > .90, P < .01). The knee joint angle at the receiving position fell below the quarter-squat position above 70% 1RM.

CONCLUSIONS

Submaximal loads were indeed optimal for maximal power output for HPC when the success criterion was set above the parallel-squat position. However, when the success criterion was defined as the quarter-squat position, the optimal load became the 1RM load.

The effects of a 4-week mesocycle of barbell back squat or barbell hip thrust strength training upon isolated lumbar extension strength

Objectives

Common exercises such as the barbell back squat (BBS) and barbell hip thrust (BHT) are perceived to provide a training stimulus to the lumbar extensors. However, to date there have been no empirical studies considering changes in lumbar extension strength as a result of BBS or BHT resistance training (RT) interventions.

Purpose

To consider the effects of BBS and BHT RT programmes upon isolated lumbar extension (ILEX) strength.

Methods

Trained male subjects (n = 14; 22.07 ± 0.62 years; 179.31 ± 6.96 cm; 79.77 ± 13.81 kg) were randomised in to either BBS (n = 7) or BHT (n = 7) groups and performed two training sessions per week during a 4-week mesocycle using 80% of their 1RM. All subjects were tested pre- and post-intervention for BBS and BHT 1RM as well as isometric ILEX strength.

Results

Analyses revealed that both BBS and BHT groups significantly improved both their BBS and BHT 1RM, suggesting a degree of transferability. However, the BBS group improved their BBS 1RM to a greater degree than the BHT group (p = 0.050; ∼11.8 kg/10.2% vs. ∼8.6 kg/7.7%, respectively). And the BHT group improved their BHT 1RM to a greater degree than the BBS group (p = 0.034; ∼27.5 kg/24.8% vs. ∼20.3 kg/13.3%, respectively). Neither BBS nor BHT groups significantly improved their isometric ILEX strength.

Conclusions

The present study supports the concept of specificity, particularly in relation to the movement mechanics between trunk extension (including pelvic rotation) and ILEX. Our data suggest that strength coaches, personal trainers, and trainees can self-select multi-joint lower-body trunk extension exercises based on preference or variety. However, evidence suggests that neither the BBS nor BHT exercises can meaningfully increase ILEX strength. Since strengthening these muscles might enhance physical and sporting performance we encourage strength coaches and personal trainers to prescribe ILEX exercise.