Influence of Acute Eccentric Exercise on the H:Q Ratio

Abstract

The purpose of the present study was to examine the effects of an acute bout of eccentric exercise on maximal isokinetic concentric peak torque (PT) of the leg flexors and extensors and the hamstrings-to-quadriceps (H:Q) strength ratio. Sixteen male (mean±SD: age=20.9±2 years; stature=177.0±4.4 cm; mass=76.8±10.0 kg) volunteers performed maximal, concentric isokinetic leg extension and flexion muscle actions at 60°·sec - 1 before and after (24-72 h) a bout of eccentric exercise. The eccentric exercise protocol consisted of 4 sets of 10 repetitions for the leg press, leg extension, and leg curl exercises at 120% of the concentric one repetition maximum (1-RM). The results indicated that the acute eccentric exercise protocol resulted in a significant (P<0.05) decrease in isokinetic leg flexion (13-19%) and leg extension (11-16%) PT 24-72 h post-exercise. However, the H:Q ratios were unaltered by the eccentric exercise protocol. These findings suggest that an acute bout of eccentric exercise utilizing both multi - and single - joint dynamic constant external resistance (DCER) exercises results in similar decreases in maximal isokinetic strength of the leg flexors and extensors, but does not alter the H:Q ratio.

The Time Course of Health, Fitness, and Occupational Performance Changes in Recruits across a Fire Academy

“…The unique responses in LE and LF strength resulted in a significant decrease in the H/Q ratio at both W15 and W30 of the academy when compared with baseline. Previous studies have suggested that a reduction in the H/Q ratio is a risk factor for hamstring and/or knee injury (20–22). The decrease in H/Q ratio at W30 of the academy in the present study may increase the risk of lower body musculoskeletal injuries in recruits as they transition into their probationary period as active-duty career firefighters.…”

“…The order of MVC was randomized before data collection. In addition, the H/Q ratio was also determined by dividing leg flexion (LF) MVC PT by leg extension (LE) MVC PT (20).…”

“…Additional work examining the impact of the training academy on the most common musculoskeletal firefighter injuries (e.g., lower extremity and low back) and simulated occupational performance may extend the work of these previous studies (14,15) and help to inform fire academy physical training recommendations that directly impact injury prevention and performance enhancement efforts. For example, the quadriceps-to-hamstring ratio and low back endurance assessments are important predictors of hamstring and/or knee injury (20)(21)(22) and low back dysfunction (23), respectively, whereas the weighted SC is considered one of the most challenging firefighter tasks (24). Thus, the purpose of the present study is to examine the impact of the fire training academy on the time course of changes in body composition, balance, vertical jump (VJ) performance, CRF, upper body (UB) and lower body strength, hamstrings-to-quadriceps ratio (H/Q), lower back endurance, and a weighted and timed SC task.…”

Isokinetic Dynamometer Leg Extensor Peak Torque Measurement: A Time-Delayed Reliability and Score Selection Analysis Study

“…A common isokinetic testing protocol for assessing PT values on an isokinetic dynamometer uses a single set model where the subjects are typically warmed-up with concentric isokinetic contractions (often following a general warm-up), briefly familiarized and then perform 1 set (per velocity) of usually ~3–5 repetitions [ 2 , 6 , 13 , 16 , 17 , 18 , 19 ]. Although some studies have used a multiple set [ 4 , 20 ] testing scheme, it remains unknown as to whether the best testing protocol for determining one’s PT performance may involve more than a single set as a potential means to optimize best performance detection and reliability. Indeed, there is some evidence that a multiple-trial muscle function test protocol may be optimal.…”

“…To further complicate the analysis, the best method for determining or selecting the PT value that best represents the person’s maximal strength is also varied and has not been well studied. For instance, PT has been reported as the single highest value of all sets/reps [ 4 , 16 , 17 , 18 , 19 , 20 ], as the mean of all values [ 13 , 17 ], and as some variation of dropping one or more values and averaging the rest of the values [ 2 , 22 , 23 ]. No consensus to date has been provided that offers investigators the most objectively superior procedures for determining how to design an optimal testing protocol and select the best PT value out of the multi-value output.…”