Participants were primarily Caucasian females with 6 to 15 years of driving experience and ranged in ages from 24 to 79 years (Table 1). The median age was 56 years, and all were right-hand dominant. Many drivers handled one horse in hand, with 12% of females driving four horses in hand. Of the male participants, 66% were overweight or obese, compared to 59% of the female drivers.

Positional HGS (Table 2) varied by sex, with males having higher HGS (p < 0.0001) than females for both positions (standing and sitting), as well as bilaterally. Within females, positional HGS was higher in both hands (p < 0.0001) while standing. Males demonstrated higher (p = 0.0375) standing HGS only in the left hand. Collectively, years of driving experience numerically had the highest values for summed standing (73.1 ± 5.2 kg) and summed sitting (59.9 ± 6.3 kg) HGS for all drivers with more than 30 years of experience. Males with 16 to 29 years of experience had the highest mean HGS in the standing position (90.9 ± 8.5 kg). Age-related normative percentiles showed males have numerically lower HGS than females at ages below 30 years. There were no associations of sex and HGE by hand or in endurance difference between dominant and non-dominant hand.

HGE category was evaluated bilaterally and by sex for associations (Table 3). There were no associations between sex and bilateral endurance difference. Within females, HGE category was greatest (Χ2 = 8.323, df = 2, p = .0156) in left hands (non-dominant) in the above 60-year age group. This effect was not seen in males in either hand or seen in female right (dominant) hands by age group.

Within females, those who drove four-in-hand tended to have higher peak sitting summed HGS than those driving one or two horses (p < 0.0653). HGS in the left hand in the sitting position and summed peak values were higher in those drivers handling four horses (p < 0.05, Table 4). There were no differences in male driver peak HGS when number of horses in hand, noting that male participants were only represented in the one-horse and two-horse teams.

Additional factors affecting hand and arm performance are summarized in Table 5. A total of 33% of males reported wearing gloves while driving, and males also reported more cold weather impacts on hand fatigue. Conversely, 78% of females wear gloves while driving, and fewer attribute fatigue to cold weather. More females reported experiencing hand fatigue while driving, with 25% attributing fatigue to the marathon phase. Drivers attributed some fatigue during practicing for events, and 16% of females reported diagnosed arthritis in the wrist or hands within the last six months.

Pain and injury reported were in the left side for joint and arthritis diagnosis (Table 6). Muscle strain/pain was predominant (80%) on the right side. No differences were realized in reported injury and summed or peak HGS by hand. No relationships between reported hand injury within the last six months and years of driving experience on HGS were identified. Additional injuries reported by females included concussion (32%), lower body including ankle, pelvis, and hip (16%), and spine (including neck, 13%). Males reported spine and shoulder injuries in equal proportion (25%) which occurred in competitive driving.

Table 7 represents the entire population as there were no differences by sex in HGE measure. To quantify the association of hand dominance and HGE, we assessed differences in the HGE category between dominant and non-dominant hands. Hand endurance measures were significant for all participants when HGE is high on the dominant hand; HGE is also high on the non-dominant hand (Table 7; Χ2 = 17.22, df = 1, p < .0001). In addition, demographic and equestrian-specific variables were included in the analysis. The same differences were realized by age, with high dominant and high non-dominant HGE associations (Table 7). Similarly, if the HGE was low in the dominant hand within age, the non-dominant HGE was also low. Those participants in the obese BMI categories were more bilaterally balanced in HGE in both the highest (high dominant/high non-dominant) and lowest (low dominant/low non-dominant) HGE (Χ2 = 12.393, df = 1, p = .0004). Those participants in the normal BMI category did not realize HGE differences between hands. The association of horses in hand demonstrated that the dominant to non-dominant hand HGE category was similar on the two ends of the spectrum: high-high, and low-low. When considering years of driving experience, those drivers with less than five years and over 30 years also followed the high-high and low-low pattern.

Engagement in barn activities, activities, and driving sports that require both strength and dexterity of hands, did not differ between sexes. On average, females complete activities 82% of the time, and males 80%. When looking within sex, females over 60 years of age reported an average of 80.8%, ages 50–60 reported 94.5%, and females under 50 reported 74%, trending towards significance. Males over 50 years old reported an average of 68% where males under 50 years old reported completing 95% of barn activities.

When observing frequencies of grip endurance and the equine-specific categories, combined drivers between 50 and 60 and under 50 (p = 0.06) tended to be different for females that complete fewer activities to have a greater difference between right and left-hand endurance (e.g. their left hand being weaker than their right). When considering effects of barn activities, dominance, and HGE for all participants, there was greater bilateral balance within the 26–74% chore category (Table 7, Χ2 = 8.997, df = 1, p = .0027). When completing over 75% of the activities, there was less bilateral balance and less frequency in the high-high category than other groups of barn activities. Glove wearing was also associated with bilateral endurance balance. For those who wear gloves, a higher proportion of endurance category balance between dominant and non-dominant (49% high-high and 29% low-low; Χ2 = 11.047, df = 1, p = .0009). Finally, HGE category was impacted by fatigue perception; following previously identified high-high and low-low category differences (Yes, Χ2 = 10.617, df = 1, p = .0011; No fatigue, Χ2 = 4.853, df = 1, p = .0279).