Title: Comparison of Body Composition and Movement Efficiency in Different Groups of Firefighter Recruits
Name: James Behnke
Primary Presenters: James Behnke, Luke Franke, Michael Hegewald
College of Health Sciences
Clinical Doctorate
Faculty Sponsor(s): Kyle Ebersole
Comparison of Body Composition and Movement Efficiency in Different Groups of Firefighter Recruits
Background and Rationale
Previous research has demonstrated links between musculoskeletal injury risk, movement efficiency (ME), and body composition among firefighters. However, differences among firefighter recruit populations remain uninvestigated. Milwaukee Fire Department has two recruit populations: those who completed the two-year Cadet program (CR) and those selected from the general population application list (GR). Our objective was to investigate differences in ME, shoulder mobility, and body composition between CR and GR firefighter recruits before their 16-week training program.
Methods
Measures of ME were collected using Fusionetics™ technology among 154 firefighter recruits (133 male, 21 female) from 2015-2019. Participants were categorized into CR and GR groups; scores were measured before a 16-week training program. Dependent variables included: overall ME scores, total impairments from ME Screen, shoulder mobility (SM) measured by Apley’s Scratch Test, and percent body fat (BF) measured by skinfold calipers. Independent t-tests were conducted in SPSS 26 and an alpha of 0.05 determined significance.
Results
Significant differences were found between groups for age (20.5±1.1 vs. 30.6±6.2 yrs., p<0.001), body weight (BW) (82.7±14.8 vs. 88.9±16.3 kg, p=0.020), BMI (26.6±3.9 vs. 28.3±5.1 kg/m2, p=0.031), BF (15.5±6.8 vs. 18.3±6.8 %, p=0.018), Right SM (11.1±6.4 vs. 16.7±8.3 cm, p<0.001), and Left SM (15.2±7.0 vs. 21.1±8.8 cm, p<0.001). Groups did not differ for height (1.7±0.1 vs. 1.8±0.1 m, p=0.378), overall ME (66.7±13.6 vs. 62.6±15.9, p=0.097) or Total Impairments (9.5±4.3 vs. 10.9±5.4, p=0.079).
Conclusions
While significant differences between groups exist in age, BW, BF, and BMI, no differences exist in ME scores. However, CRs had significantly better shoulder mobility than GR’s. This suggests GRs may need specific shoulder mobility interventions while both CRs and GRs could benefit from overall mobility interventions before stressing their joints with heavy loads. Future research should investigate effects of academy training programs on shoulder mobility, movement ability and other fitness measures.
I think the lack of difference in the ME measures in these two groups is pretty interesting. Also, while we seem to think that increased shoulder mobility is generally a good thing, I am curious about any shoulder injury data for the two different groups. Specifically, I wonder if increased shoulder mobility may actually make an individual MORE prone to shoulder injury given the tasks these individuals perform.
I agree, we know that shoulder injuries are very common among firefighters so an interesting comparison could be made between those with increased vs decreased mobility who went on to have shoulder injuries.
Very interesting stuff. Any guesses as to why the general population has more restricted shoulder ROM than the cadet population? My guess is the 10 year age gap, but then again being 30 doesn’t seem like “old enough” to start getting stuff and losing ROM.
Our initial thoughts were the age gap although that is a good point, 30 does not seem as old as one might expect. It could be that the general population recruits did not spend as much time in their 20s working on mobility but rather focused heavily on building strength. It would be interesting to compare their data to the cadets when they reach the age of 30 to see if incorporating mobility into their workout routine throughout their 20s makes any difference.
Jimmy, Luke and Michael, the lack of a difference in movement efficiency between groups of different BMIs gives me hope! 🙂 Seriously, it is interesting that the lower extremity tests were not affected, but that the shoulder tests were (although I believe that was between the two groups and not necessarily related to BMI). Great job!
Interestingly, previous research showed that BMI may have less of an influence on overall movement efficiency scores in firefighters than in other populations.
Cornell, D. J., Gnacinski, S. L., Zamzow, A., Mims, J., & Ebersole, K. T. (2016). Influence of body mass index on movement efficiency among firefighter recruits. Work (Reading, Mass.), 54(3), 679–687. https://doi.org/10.3233/WOR-162306
I also wondered about age as an explanation, even if still “young.” The question about injury is one to explore, as well. Great work.