Search Results

You are looking at 1 - 6 of 6 items for

  • Author: Terry L. Grindstaff x
Clear All Modify Search
Restricted access

Joseph B. Lesnak, Dillon T. Anderson, Brooke E. Farmer, Dimitrios Katsavelis and Terry L. Grindstaff

Context: Resistance training exercise prescription is often based on exercises performed at a percentage of a 1-repetition maximum (1RM). Following knee injury, there is no consensus when a patient can safely perform 1RM testing. Resistance training programs require the use of higher loads, and loads used in knee injury rehabilitation may be too low to elicit gains in strength and power. A maximum isometric contraction can safely be performed during early stages of knee rehabilitation and has potential to predict an isotonic knee extension 1RM. Objective: To determine whether a 1RM on an isotonic knee extension machine can be predicted from isometric peak torque measurements. Design: Descriptive laboratory study. Setting: University research laboratory. Participants: A total of 20 (12 males and 8 females) healthy, physically active adults. Main Outcome Measures: An isokinetic dynamometer was used to determine isometric peak torque (in N·m). 1RM testing was performed on a knee extension machine. Linear regression was used to develop a prediction equation, and Bland–Altman plots with limits of agreement calculations were used to validate the equation. Results: There was a significant correlation (P < .001, r = .926) between peak torque (283.0 [22.6] N·m) and the knee extension 1RM (69.1 [22.6] kg). The prediction equation overestimated the loads (2.3 [9.1] kg; 95% confidence interval, −15.6 to 20.1 kg). Conclusions: The results show that isometric peak torque values obtained on an isokinetic dynamometer can be used to estimate 1RM values for isotonic knee extension. Although the prediction equation tends to overestimate loads, the relatively wide confidence intervals indicate that results should be viewed with caution.

Restricted access

Rebecca J. Bedard, Kyung-Min Kim, Terry L. Grindstaff and Joseph M. Hart

Objective:

To compare active hamstring stiffness in female subjects with and without a history of low back pain (LBP) after a standardized 20-min aerobic-exercise session.

Design:

Case control.

Setting:

Laboratory.

Participants:

12 women with a history of recurrent episodes of LBP (age = 22.4 ± 2.1 y, mass = 67.1 ± 11.8 kg, height = 167.9 ± 8 cm) and 12 matched healthy women (age = 21.7 ± 1.7 y, mass = 61.4 ± 8.8 kg, height = 165.6 ± 7.3 cm). LBP subjects reported an average 6.5 ± 4.7 on the Oswestry Disability Index.

Interventions:

Participants walked at a self-selected speed (minimum 3.0 miles/h) for 20 min. The treadmill incline was raised 1% grade per minute for the first 15 min. During the last 5 min, participants adjusted the incline of the treadmill so they would maintain a moderate level of perceived exertion through the end of the exercise protocol.

Main Outcome Measures:

During session 1, active hamstring stiffness, hamstring and quadriceps isometric strength, and concurrently collected electromyographic activity were recorded before and immediately after the exercise protocol. For session 2, subjects returned 48–72 h after exercise for repeat measure of active hamstring stiffness.

Results:

Hamstring active stiffness (Nm/rad) taken immediately postexercise was not significantly different between groups. However, individuals with a history of recurrent LBP episodes presented significantly increased hamstring stiffness 48–72 h postexercise compared with controls. For other outcomes, there was no group difference.

Conclusions:

Women with a history of recurrent LBP episodes presented greater active hamstring stiffness 48–72 h after aerobic exercise.

Restricted access

Jihong Park, Terry L. Grindstaff, Joe M. Hart, Jay N. Hertel and Christopher D. Ingersoll

Context:

Weight-bearing (WB) and non-weight-bearing (NWB) exercises are commonly used in rehabilitation programs for patients with anterior knee pain (AKP).

Objective:

To determine the immediate effects of isolated WB or NWB knee-extension exercises on quadriceps torque output and activation in individuals with AKP.

Design:

A single-blind randomized controlled trial.

Setting:

Laboratory.

Participants:

30 subjects with self-reported AKP.

Interventions:

Subjects performed a maximal voluntary isometric contraction (MVIC) of the quadriceps (knee at 90°). Maximal voluntary quadriceps activation was quantified using the central activation ratio (CAR): CAR = MVIC/(MVIC + superimposed burst torque). After baseline testing, subjects were randomized to 1 of 3 intervention groups: WB knee extension, NWB knee extension, or control. WB knee-extension exercise was performed as a sling-based exercise, and NWB knee-extension exercise was performed on the Biodex dynamometer. Exercises were performed in 3 sets of 5 repetitions at approximately 55% MVIC. Measurements were obtained at 4 times: baseline and immediately and 15 and 30 min postexercise.

Main Outcome Measures:

Quadriceps torque output (MVIC: N·m/Kg) and quadriceps activation (CAR).

Results:

No significant differences in the maximal voluntary quadriceps torque output (F 2,27 = 0.592, P = .56) or activation (F 2,27 = 0.069, P = .93) were observed among the 3 treatment groups.

Conclusions:

WB and NWB knee-extension exercises did not acutely change quadriceps torque output or activation. It may be necessary to perform exercises over a number of sessions and incorporate other disinhibitory interventions (eg, cryotherapy) to observe acute changes in quadriceps torque and activation.

Restricted access

Rebecca J. Guthrie, Terry L. Grindstaff, Theodore Croy, Christopher D. Ingersoll and Susan A. Saliba

Context:

Individuals with low back pain (LBP) are thought to benefit from interventions that improve motor control of the lumbopelvic region. It is unknown if therapeutic exercise can acutely facilitate activation of lateral abdominal musculature.

Objective:

To investigate the ability of 2 types of bridging-exercise progressions to facilitate lateral abdominal muscles during an abdominal drawing-in maneuver (ADIM) in individuals with LBP.

Design:

Randomized control trial.

Setting:

University research laboratory.

Participants:

51 adults (mean ± SD age 23.1 ± 6.0 y, height 173.6 ± 10.5 cm, mass 74.7 ± 14.5 kg, and 64.7% female) with LBP. All participants met 3 of 4 criteria for stabilization-classification LBP or at least 6 best-fit criteria for stabilization classification.

Interventions:

Participants were randomly assigned to either traditional-bridge progression or suspension-exercise-bridge progression, each with 4 levels of progressive difficulty. They performed 5 repetitions at each level and were progressed based on specific criteria.

Main Outcome Measures:

Muscle thickness of the external oblique (EO), internal oblique (IO), and transversus abdominis (TrA) was measured during an ADIM using ultrasound imaging preintervention and postintervention. A contraction ratio (contracted thickness:resting thickness) of the EO, IO, and TrA was used to quantify changes in muscle thickness.

Results:

There was not a significant increase in EO (F1,47 = 0.44, P = .51) or IO (F1,47 = .30, P = .59) contraction ratios after the exercise progression. There was a significant (F1,47 = 4.05, P = .05) group-by-time interaction wherein the traditional-bridge progression (pre = 1.55 ± 0.22; post = 1.65 ± 0.21) resulted in greater (P = .03) TrA contraction ratio after exercise than the suspension-exercise-bridge progression (pre = 1.61 ± 0.31; post = 1.58 ± 0.28).

Conclusion:

A single exercise progression did not acutely improve muscle thickness of the EO and IO. The magnitude of change in TrA muscle thickness after the traditional-bridging progression was less than the minimal detectable change, thus not clinically significant.

Restricted access

Marissa C. Gradoz, Lauren E. Bauer, Terry L. Grindstaff and Jennifer J. Bagwell

Context: Hip rotation range of motion (ROM) is commonly assessed in individuals with lower extremity or spine pathology. It remains unknown which hip rotation ROM testing position is most reliable. Objective: To compare interrater and intrarater reliabilities between hip internal rotation (IR) and external rotation (ER) ROM in supine and seated positions. Study Design: Controlled laboratory study. Setting: University research laboratory. Participants: A total of 19 participants (11 females and 8 males; age = 23.5 [1.2] y; height = 173.2 [8.6] cm; and mass = 69.2 [13.4] kg) without hip, knee, low back, or sacroiliac pain within the preceding 3 months or history of hip or low back surgery were recruited. Interventions: Three testers obtained measures during 2 testing sessions. Passive supine and seated hip IR and ER ROM were performed with the hip and knee flexed to 90°. Main Outcome Measures: The primary outcome measures were hip IR and ER ROM in supine and seated positions (in degrees). Interrater and intrarater reliabilities were calculated using intraclass correlation coefficients (ICCs). Minimal detectable change was calculated. Differences between supine and seated hip IR and ER ROM values were assessed using paired t tests (significance level was .05). Results: Supine hip IR and ER ROM interrater and intrarater reliabilities were excellent (ICC = .75–.91). Seated hip IR ROM interrater and intrarater reliabilities were good (ICC = .64–.71). Seated hip ER ROM interrater reliability was good (ICC = .65), and intrarater reliabilities were good to excellent (ICC = .65–.82). Minimal detectable change values for supine and seated hip IR and ER ROM ranged from 6.1° to 8.6°. There were significant differences between supine and seated positions for hip IR and ER ROM (41.6° vs 44.5°; P < .01 and 53.0° vs 44.2°; P < .01, respectively). Conclusion: Supine hip rotation had higher interrater and intrarater reliabilities. Hip IR and ER ROM values differed significantly between supine and seated positions and should not be used interchangeably.

Restricted access

Daniel H. Huffman, Brian G. Pietrosimone, Terry L. Grindstaff, Joseph M. Hart, Susan A. Saliba and Christopher D. Ingersoll

Context:

Motoneuron-pool facilitation after cryotherapy may be mediated by stimulation of thermoreceptors surrounding a joint. It is unknown whether menthol counterirritants, which also stimulate thermoreceptors, have the same effect on motoneuron-pool excitability (MNPE).

Objective:

To compare quadriceps MNPE after a menthol-counterirritant application to the anterior knee, a sham counterirritant application, and a control treatment in healthy subjects.

Design:

A blinded, randomized controlled laboratory study.

Setting:

Laboratory.

Participants:

Thirty healthy subjects (16 m, 14 f; 24.1 ± 3.9 y, 170.6 ± 11.4 cm, 72.1 ± 15.6 kg) with no history of lower extremity surgery volunteered for this study.

Intervention:

Two milliliters of menthol or sham counterirritant was applied to the anterior knee; control subjects received no intervention.

Main Outcome Measures:

The average vastus medialis normalized Hoffmann reflex (Hmax:Mmax ratio) was used to measure MNPE. Measurements were recorded at 5, 15, 25, and 35 minutes postintervention and compared with baseline measures.

Results:

Hmax:Mmax ratios for all groups significantly decreased over time (F 4,108 = 10.52, P < .001; menthol: baseline = .32 ± .20, 5 min = .29 ± .18, 15 min = .27 ± .18, 25 min = .28 ± .19, 35 min = .27 ± .18; sham: baseline = .46 ± .26, 5 min = .36 ± .20, 15 min = .35 ± .19, 25 min = .35 ± .20, 35 min = .34 ± .18; control: baseline = .48 ± .32, 5 min = .37 ± .27, 15 min = .37 ± .27, 25 min = .37 ± .29, 35 min = .35 ± .28). No significant Group × Time interaction or group differences in Hmax:Mmax were found.

Conclusions:

Menthol did not affect quadriceps MNPE in healthy subjects.